Alcohol, fantastic. Never thought of that, always used my finger....ouch. You can see the discoloration from heat on the microprocessor. Thanks for the video have a great weekend.
Great instructional video. At the low price of the radio I would be surprised if the repair labor alone would not exceed the cost of a replacement radio. Hopefully your reminder to ensure the pinouts of any replacement cable are correct will help to keep someone from toasting their electronic equipment.
Hi this was a really educational video. You not only discovered the problem but you determined the cause. People should be reminded that the cables that comes with these devices are proprietary and are not the same as USB cabled that can be used for charging or data transferring. If i did't see this video I would have definitely used an Ethernet Cable instead for a longer reach and frying my device.
I learned... 1: Alcohol trick, 2: LAN cables as extensions can be dangerous. That radio goes in Parts bin until another comes along to pillage. Thanks for this detailed experience.
Correctly wired lan cables do not have turnovers. But the original cable that comes with the front panel may very well have a turnover. So you can use a lan cable as an extension cable, but you can't replace the original cable with one. You have to use them both together.
@@stargazer7644 ever heard of a network cable pinout tester? you can replace the cable no problem as long as you do it as it is in the original, my guess, straight cable.
Thanks for the video Peter. I thought I saw a shadow at the center of the IC before application of the alcohol. I like the alcohol test. I have not seen this done previously.
I have one of these radios and have had good success using it with the supplied RJ extension cable for extending the faceplate. Looking at the pin function arraignment on the drawing makes me think that it would be dangerous to insert or remove the RJ connector while the main 13.8VDC supply is connected to the radio. So I see this as a lesson learned. So if the RJ connector ever pops out, NEVER just pop it back in without removing the main power first. I'm betting that's what happened here. Thank you, this was very informative. Well done.
The problem is even if you had a processor it still wouldn't be of much use. Most of this type radio have their alignment done through programming at time of manufacturer. The alignment tables are stored on the micro.
@simplio Not trying to be a smart a$$ but using that logic you should probably throw your cellphone away and every other electronic gadget that uses a microprocessor. Radios like this are a great for someone just starting out in amateur radio. They are economically practical for those on a tight budget and gets them on the air. I repair radios for a living and it's rare, very rare for a micro to go bad. How many 10's if not 100's of millions of amateur radios, CB radios, FRS/GMRS radios and public service radios are out there in the world with microprocessors and they work just fine day in and day out. Is there the rare radio that has a problem like this, sure but it's just that, rare. Custom micro's have been in use in consumer radios since the 70's. Shoot, I had a 1976 vintage CB radio on the bench the other day and even it has a custom masked ROM that is used to control the PLL synthesizer circuit. If there is anything to complain about with the cheap import radios it's the lack of service information. 90+% of the import radios like this have no service information published on them making them at least hard if not impossible to troubleshoot.
Excellent video as always Peter. Thank you for taking your time and explaining these fault finding techniques. Also, explaining complex procedures in a language that is not your primary one can't be easy, but you do an excellent job of it. Thank you, Peter, 73, Keith McDonnell
That alcohol trick is genius. Similar results with a inferred camera but way cheaper. Just as effective. You can put alcohol on any suspected component and tell immediately if the alcohol goes away. Thanks for sharing.
nice... somehow i knew from the beginning that someone tried to connect the pannel with standard LAN cable i got that feeling...:) BEWARE NEXT TIME FOLKS!!! good job as always mr. TRX Bench. I like your videos very much. greetings
A great video and a great way to troubleshoot. I have exact this device and have recently connected it reversed. The 15 amp fuse goes off. After renewing the fuse and connecting the device with the correct polarity, release the fuse again. I remembered your video and looked at it again. The resistor between the two supply lines was 0 ohms. I decided to remove the small diode. After that, the device worked again. Well in my case, the diode has done its job and has protected the device. I will get a new diode and install it in the device, so that the device protection is restored. Thanks for the inspiration I had through your Viedo to find the fault myself.
I have this radio, you have to hold the power button for 2 or 3 seconds for it to power on, just a momentary press of the button will not turn mine on.
Thats the first thing I noticed and wondered through the entire video if there were nothing wrong with the radio in the first place.. was all of this due to an organic interface error? Could they have saved time and money by simply reading the manual? LOL.. will never know.. but wont send my stuff to this guy for sure!
Thanks for this Peter - I have one of those inexpensive TYT handhelds, and I know if it "goes away" Ill only be out $100.... At least the owner of that radio will learn not to hook up an extension that is not made for it.
I really enjoyed the value of this radio when first purchased... Unfortunately I have had 4 of them all go bad for various reasons, non of them abused in anyway and now they are just scrap radios. Won't purchase any more. Good video👍
I have the Yaesu version, still going strong but not used much anymore. I hated it in my work truck, such small fiddly knobs and buttons in a rough 4x4 truck. I was constantly knocking it of frequency or enabling wires-x accidentally. Also I couldn't tell what the volume level was set at easily. You would drive off the road trying to read the display or adjust anything. Its my spare back up radio now.
Peter is holding the (used) parts supply chain in his hand! His well educated guess about NOT using an ethernet cable to extend your face plate... priceless ! Appears to be well built, so perhaps without abuse, you might get the expected couple of decades of use out of a new one.
Great Trouble shooting on your part... It's a shame there is no replacement . Thanks for sharing this video I almost purchased one as a 10 meter mobile radio but learned it was only FM and I was looking for Side Band mode.... Thank You again... 73's KC3ZDW
Very nice video Peter anyways. We always learn something with your Videos. Really a its odd having to lose a "nice" radio because a lack of spare parts.... Thx for sharing your time with us again
I forget sometimes that not everybody is familiar with the notation conventions of digital electronics. The notation "INTn" where "n" is some number generally indicates an interrupt input, the bar over it means "active low". The slashes mean alternative uses. In this case, P1_7/TRAIO/INT1 and I think that's the physical pin name, one thing it could be for, and the other thing it could be for. INT1 is interrupt input 1, but it took some digging to find out what TRAIO means. It's apparently the I/O pin for Timer RA. Totally clear, right? Digging into the data sheet (hey, sometimes I read data sheets just for fun) I find that RA is just the name for one of the timers (there are also RB, RC, RD, and so forth) and it can be used as an input or an output depending on what mode the timer is in, so (without doing any more digging because I'm already late for work) I'd expect that the timer can either measure the time between input pulses or emit a pulse train or similar, and this is the pin that does that. Without looking at the software at all, because it's not available, it seems likely that this pin would be configured to be used as an interrupt input. When you apply power to the radio, the CPU powers up, but nothing else does and it waits in a low-power mode until it receives that interrupt (due to someone pressing the button) and then the interrupt service routine would trigger the CPU to power the rest of the radio up.
Well, the CPU is available via RS-online for about 5€ and the firmware can actually be downloaded from TYT. Of course you'd still need the equipment to flash it.
@@stevejones8665 They don't have any firmware available just a configuration program similar to Chirp that has access to the extra features but when I try to run it I get an error.
Many of the comments here brought out noteworthy issues....like, even if you did replace the Regulator, the Zener, and the processor, it might still be useless because of information missing in the new processor. Excellent video, thanks!
I just took one in from a customer, completely dead, no lights, no fan, nothing. I found that the power input had a dead short. After downloading the diagram, I first suspected some of the capacitors. It was easy to remove two electrolytic caps, but they were not the problem. There is a zener diode, I think it was D30. It had a dead short. It is an 18 volt zener, appears to be 5 watts. The zener is in normal operation, reverse biased, so that if the 18 volts is approached, the voltage would be limited or clamped. In this case, I suspect the customer had reverse polarity, which in this case would have shorted the power supply, until something gives up, in this case, the zener shorted, saving the radio. Jim
On a CPU “INTx” generally means “interrupt”. In this case it would be an external hardware interrupt to “wake up” the CPU from its low power “sleep” state whenever the power button is activated so that the CPU can wake up and process the event appropriately despite being asleep...or interrupt normal execution to power off the radio if it was already powered on. On CPUs interrupts can be either hardware or software defined events and they are dedicated routines that “interrupt” the normal program execution on the CPU so that the CPU can momentarily execute some dedicate code to address the event associated with the interrupt event. Hardware interrupts can also wake up a sleeping CPU in addition to triggering the execution of the code associated with the interrupt. Once the interrupt routine code has finished executing the CPU goes returns to normal program execution until the next interrupt event occurs.
Hi Peter, The method to determine heat with applied alcohol is so close, but I've never come up with this idea. Great, I learned something there. Thank you! I also operate such a TYT device. Back when I bought it, I thought that I could also build this remote cable myself and thought of an Ethernet cable : -o I found an offer with cable included while browsing and I bought this. Sure, I would also had toasted my TRX with a self-built cable. So I learned something again ..... Thank you for your work and the video. 73 Bernd
Hi Mr. Peter, and sorry for my little English. In the video you can see very well that in the beginning, you "try" to turn on the transceiver, but it doesn't even turn on. To make it turn on, however (!), You press and very briefly release the power button. Well, ....... by doing so, .... it will NEVER turn on! Because the manufacturer has provided for its ignition, that the ignition key must be "kept" "pressed" for about 4 (four) seconds, before turning on! I explain this because, owning it, on the first day of purchase I also thought it was broken, because pressing the power button, as you did in the video, it did not turn on. Then I tried to keep it pressed (instead of just pressing it as you did), and it turned on very regularly and is fully functional. Even a friend of mine, who bought it after me, called me for help because it didn't turn on ........ but as soon as I explained to him that the power button had to be kept pressed for a few seconds .... .I call back happy telling me that it worked perfectly. So ... be careful to make judgments ... before you know how a product works. Then I noticed that you try to "denigrate" the product, ... and only for pure "racism" because it is of Chinese origin ....... But here he is wrong ...... because if he has noticed the components inside ...... it is "strangely" ALL Japanese Original. And if you had better informed, rather than to show off the cheesy "racism", .. ... you would discover that, in REALITY, that Transceiver was ALL produced by the Japanese Yaesu Musen with only few very small changes ... which company then "granted" the exploitation and resale of its product, to Tytera (TYT), on lavish "payment". So .... that product is a Made in Japan product ...... "rebranded" TYT. And ... so ... it's not Chinese .... Greetings of a Happy New Year
Thank you once again, Peter, for an exceptional video. I really enjoy your fault finding techniques. You explain things in a language that I can understand. Your English is excellent. I doubt that I could follow you if this were in German. I have 2 classes in spoken German but if you don't use it every day, you tend to forget the words and sentence structure. German does have a sentence structure that translates quite well into English. Excellent video on this Chinese radio. Only Chinese radio I own is a Baofeng UV-5RE that a friend opened up to 1.25 (meter or centimeter??); anyway the 220MHz band. The tri-band antenna cost double the radio cost. A nice technique with the alcohol on the CPU--I've never seen that before. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee
thank you for the excellent video i have the tyt-9800 but lost receive on 2 mtrs only and the advise is true due to the cost of this new the radio as been left until a long rainy day to have a look.
I have the TYT radio and I have to hold the power button for 2-3 full seconds or longer to get it to "power up". I know this video is a couple years old, but I didn't see you hold the power button for longer than a fraction of a second? Maybe hold the power button for a bit longer next time?
You're right,probably the front panell it's toasted too because somebody tried to extend the panell from the body using a LAN cable,but i'm so curiouse to see that radio totally fixed...:)
Buenas noches, en primer lugar darle las gracias por este magnífico vídeo ,así como también a todos los corresponsales que han intervenido con sus comentarios, tengo una radio igual qué esa ,después de abrirla sacar la placa me encuentro con el regulador U41 en corto el diodo de 5,6V en corto la resistencia r40 de 100 homios abierta el diodo zener doble Q407 destruido y componentes por la parte de abajo de la placa justamente de bajo de U41 chamuscados también para cambiar y curiosamente hay un componente con referencia 0R según el esquema al lado del diodo D110 que esta en cortocircuito, al medirlo ,pero que parece una resistencia 0 aunque en el esquema viene como un condensador.bueno lo dicho gracias a todos cuando reciba los componente los insertaré y a ver que pasa.saludos.
If you make sure the extension cable you buy is straight wired, this should not happen. In this case, the right cable would be an R12 6P6C straight through, duplicating the wiring of the factory short cable that links to the head unit when it's mechanically connected to the radio body. It would have been very helpful to have the owner provide the cable he or she used so its wiring could be verified, but it seems it was not a straight through but rather was some sort of fax machine cable. Lesson learned.
Just got a used toasted TH-9800. Similar to yours, EXCEPT it blows fuses at initial power application (not via switch). We shall see...thanks, I will use what you did....
I have 2 of the same and both had to be sent back to China for repairs. There are 4 IF filters and the circuit in my view is bad. They had to be sent back to China 2 times for the same issue
i OWN THIS RADIO, IT WILL NOT TURN ON WITH A SHORT TAP !!! PROPER TURN ON IS TO HOLD POWER BUTTON AT LEAST 1 SECOND. The radio is a huge success in my mobile ARES vehicle. 73 - KV4WM, a US Navy Nuclear Submarine Veteran.
Your video started off similar to my experience, I do not have 13 volts at FB on the front connector. I have a known good radio that does have FB present when power is off. So it is mislabeled as SBE. I cannot figure out why it's not getting power at FB on the connector side. I jumped it temporarily and chip u118 started to get hot. That is my next culprite
I had the same thing happen with the same radio brought to me. Luckily, I had another 9800 with a burned pcb that I was able to swap out the cpu and diode. I up-rated the regulator, feeling this is a vulnerable part. What a shame it is a death and TYT not being close to hand. Might be worth a try contacting them, but hey-ho, these radios are cheap enough. Thank you for the tip: re the Ethernet cable. This would not have ocurred to me.
I have the same issue with cheap Chinese UHF CB (Australian 477 MHz band) radios. They are just so cheap that it's not even worth replacing a shorted zener diode on the input supply leads.
@@jeromegrzelak8236 No. Back 10 years ago when the CCR's were rumored to be hitting the market, the ham radio community raved about how cheap they would be to buy and how they would be a "throw away radio". Well, CCR's are here and you need to own up to the ranting about how they are throw away radios. Throw them away. Stop flooding the internet with this garbage about fixing a $30 CCR handheld. Even the MFG's who make this crap don't fix them because the cost for shipping alone often is more than the value of the radio.
hi peter where can i get the schematic and the other service manual information that you are using as my th9800 as developed a problem with the 2 mtrs band no recieve. thanks for any information you could help me with
Watchmaker's putty. It has many great uses. Get yourself a stick of it. And if you are not happy with it, I'll give you your money back. Besides cleaning my tweezers and screwdriver tips, I spread a thin layer of it to help keep tiny components from moving and hopping around when I am trying to test them.
I got this radio as my first non-HT. 10meter and 6 meter FM are very interesting! Mine is the "Improved" version whatever that means....I've run it through a lot, including cross band use and it handles it like a champ but I do worry about running it on high power. I definitely don't get 50watts on it unless I am on a 25amp+ power supply.....30watts on high power is the best I get on a 12amp PSU.
I suggest you remove the pcb and fan. Drill out the back of the case to allow the air to flow internally over the PA and the pcb, then drill three slots in the lid as an outflow for the hot air. You can then run high power knowing you will not blow up the radio's PA. You learn these tricks as you go along life's ham radio highway. Also change out the regulators for the 1.5A (TO220 type) and heat sink them using thermal compound. Long life will ensue. Happy days.
Notwithstanding the fault, this radio needs the power button to be held in for a second or two before power will be applied. Quickly pressing the button as shown in this video will not power up the radio even when it is working. Otherwise, thanks :-)
also I purchased a warranty with the radio and have used it once, parts are available and it can be fixed. Otherwise in the last two years it has been issue free and I constantly get positive comments on how good the radio sounds.
I have one of these radios it came to me from China with two bulged chips that looked like they where heatguned to death. It has not failed me so far. And I use it as an everyday beater in my Lincoln I have had it for over 3 years now. Works ok as a gmrs radio on my mfj night rider antenna. I know the mfj nr antenna is really for the70cm and 2 meater ham band but it's a good enough swr and vswr for my needs. I have a 1.1>2 on 2 meters and a 1.1>3 on 70 cm and a 1.2>4 on 462-467 mhz ehh it's a Chinese radio iam not going to bother to put an antenna switcher and multiple antennas on my car. As it is the tweakers here think I have a cb am radio. And I get tired of explaining to everybody that asks that it's a ham radio Chinese knock off of a yeasu 8900 quad band Usealley by this time I get a funny look on there face.
I had bought one and connected it to my bench power supply. Ran it for 15 minutes and then connected a watt meter with no problems with a quick transmit. I let it sit just to receive for about two hours then it quit. The display goes dead, the radio starts pulling more current. Shipped it back and bought a Yeasu instead and have had zero problems with it. It's a hit and miss with these radios the quality control is lacking.
I think J114 is for the front panel display panel, I need to know what the pin-outs are for the mike!!, please see the next comment I left for you, tnx. comment
The diode was not effective maybe a little slow and not efficient I think it lacked a small current limitation in it, excellent video hugs from Brazil Peter.
More likely, just too much sustained current as a Zener is quite fast at clamping, but you still have the issue of impedance limiting its ability to protect if overwhelmed by current. That said, the Zener was almost certainly selected to provide ESD protection since it leads to an external jack rather than a sustained over-voltage event from getting the connections swapped. Ideally TYT would never have sent unlimited 13.8VDC direct to the front panel through that connector. If they had limited the front panel to 5VDC then the swapped connections would have remained within the safe 5V limit the CPU could handle and no serious harm would have been done so long as the resulting current was not sufficient to burn through PCB traces. On the Yaesu FT-8900 that this radio is supposed to be a “functional” clone of, the front panel voltage is provided by way of an 8V linear regulator which should have then gone into overcurrent protection upon shorting of the Zener and would have likely then protected the radio - Yaesu did not just pass 13.8VDC straight through to the front panel. I’ve not studied their schematic for the head unit port, but I would hope Yaesu implemented better overall protection for that port (and strongly suspect they have, not that I’m going to intentionally short out either of my FT-8900 front panel interfaces just to test that hypothesis!).
Again, very nice video, the alcohol test was a new one for me. What a shame, I was really hoping to see you replace the CPU, however like you said, more IC’s also could have shorted from the high voltage getting through the shorted Zener. Would have been interesting to see if the removal of the vcc +5v power pin of cpu, or complete removal, would have lifted the short on the 5v line. If so, maybe all it needs then is a new CPU “if can be found somewhere” and new Zener Diode?
I have an issue with mine. Right side had bad receive on both bands (2/70) and does not transmit audio, just carrier and you can hear dtmf tones. Left side the same but receive is ok on 2m/70 cm. I can also transmit and receive on 10m and 6m on the left. Any ideas where to focus?
Not economically feasable to pay for repairs on a robot built radio, only parts will come from another dead radio. I own one I have never taken out of the box. Wont use it where my my life depends on it.. that's for sure. BTW this is a clone of the Yaseu FT 8900.
I wonder why the sellers of this model radio are making false claims about it saying that it can receive a wide range of: 26-33Mhz, 47-54 MHz, 110-180Mhz ( with AM Air band), 350-399Mhz, 430-512Mhz, and 750-947Mhz? That's not true, it can only get 4 Ham bands. I was thinking of buying one until I tried it and found that it doesn't get the frequencies they claim.
Frequency range supported can depend on country of import. For example, in U.S., the FCC (Federal Communications Commission) requires amateur radios to be limited regards transmit frequency range in each of the bands, to prevent out-of-band use. Imported to Australia, the programming would be different.I think there are work-arounds; a little Internet searching will answer that for you. KI7ZEI
@@timhaupt5270 That's not true when you buy it on Ebay coming from China. The receive frequency is also limited to 29/50/144/430 Mhz. and there is no work around. It's odd that all the sellers still claim a wide frequency range but they seem to just be copying bad information from the TYT website.
Peter I recently purchased the tyt th9800. Wondering if you have experienced the radio not turning off. Out of the blue decided to turn on its own, now unable to turn it off, holding down the power button nothing. Unhook the power goes off ,wait a few plug-in the power it turns on with out pushing the power button. What do u think
![Дон ДОН, Алаудинов и СБЕЖАВШИЕ из под Курска ахматовцы 😁 [Пародия]](http://i.ytimg.com/vi/dEfCf5IK26Q/mqdefault.jpg)
Excellent video Peter, thank you so much for going through your fault finding process. Your alcohol test on the cpu was worth watching on its own.
Alcohol, fantastic. Never thought of that, always used my finger....ouch.
You can see the discoloration from heat on the microprocessor.
Thanks for the video have a great weekend.
The most inteligent repair video series I have seen. always a pleasure.
Great instructional video. At the low price of the radio I would be surprised if the repair labor alone would not exceed the cost of a replacement radio. Hopefully your reminder to ensure the pinouts of any replacement cable are correct will help to keep someone from toasting their electronic equipment.
Hi this was a really educational video. You not only discovered the problem but you determined the cause. People should be reminded that the cables that comes with these devices are proprietary and are not the same as USB cabled that can be used for charging or data transferring. If i did't see this video I would have definitely used an Ethernet Cable instead for a longer reach and frying my device.
I learned... 1: Alcohol trick, 2: LAN cables as extensions can be dangerous. That radio goes in Parts bin until another comes along to pillage.
Thanks for this detailed experience.
Correctly wired lan cables do not have turnovers. But the original cable that comes with the front panel may very well have a turnover. So you can use a lan cable as an extension cable, but you can't replace the original cable with one. You have to use them both together.
@@stargazer7644 ever heard of a network cable pinout tester? you can replace the cable no problem as long as you do it as it is in the original, my guess, straight cable.
Thanks for the video Peter. I thought I saw a shadow at the center of the IC before application of the alcohol. I like the alcohol test. I have not seen this done previously.
I have one of these radios and have had good success using it with the supplied RJ extension cable for extending the faceplate. Looking at the pin function arraignment on the drawing makes me think that it would be dangerous to insert or remove the RJ connector while the main 13.8VDC supply is connected to the radio. So I see this as a lesson learned. So if the RJ connector ever pops out, NEVER just pop it back in without removing the main power first. I'm betting that's what happened here. Thank you, this was very informative. Well done.
no not really as it turned out that no power is on the front panel as long it is switched off.
The problem is even if you had a processor it still wouldn't be of much use. Most of this type radio have their alignment done through programming at time of manufacturer. The alignment tables are stored on the micro.
Mike, you should update your avatar ;-)
@simplio
Not trying to be a smart a$$ but using that logic you should probably throw your cellphone away and every other electronic gadget that uses a microprocessor. Radios like this are a great for someone just starting out in amateur radio. They are economically practical for those on a tight budget and gets them on the air. I repair radios for a living and it's rare, very rare for a micro to go bad. How many 10's if not 100's of millions of amateur radios, CB radios, FRS/GMRS radios and public service radios are out there in the world with microprocessors and they work just fine day in and day out. Is there the rare radio that has a problem like this, sure but it's just that, rare. Custom micro's have been in use in consumer radios since the 70's. Shoot, I had a 1976 vintage CB radio on the bench the other day and even it has a custom masked ROM that is used to control the PLL synthesizer circuit. If there is anything to complain about with the cheap import radios it's the lack of service information. 90+% of the import radios like this have no service information published on them making them at least hard if not impossible to troubleshoot.
@@OleF112
LOL, that is a pretty old picture isn't it. It's so old I still had my Stabilock 4040 communications test set on the bench.
@@mikesradiorepair Mike, have a close look at my pic...Where´s Waldo :-) Thats my second desk for long term repairs;-) Still like the 4040
@@mikesradiorepair Oh yeah, need new pix with the R&S box!
Excellent video as always Peter. Thank you for taking your time and explaining these fault finding techniques.
Also, explaining complex procedures in a language that is not your primary one can't be easy, but you do an excellent job of it.
Thank you, Peter, 73,
Keith McDonnell
Thank you for the kind words Keith very much appreciated! 73
That alcohol trick is genius. Similar results with a inferred camera but way cheaper. Just as effective. You can put alcohol on any suspected component and tell immediately if the alcohol goes away. Thanks for sharing.
Nice and clear story of how to find the problem. Thank you a lot.
nice... somehow i knew from the beginning that someone tried to connect the pannel with standard LAN cable i got that feeling...:) BEWARE NEXT TIME FOLKS!!! good job as always mr. TRX Bench. I like your videos very much. greetings
A great video and a great way to troubleshoot. I have exact this device and have recently connected it reversed. The 15 amp fuse goes off. After renewing the fuse and connecting the device with the correct polarity, release the fuse again. I remembered your video and looked at it again. The resistor between the two supply lines was 0 ohms. I decided to remove the small diode. After that, the device worked again. Well in my case, the diode has done its job and has protected the device. I will get a new diode and install it in the device, so that the device protection is restored. Thanks for the inspiration I had through your Viedo to find the fault myself.
I have this radio, you have to hold the power button for 2 or 3 seconds for it to power on, just a momentary press of the button will not turn mine on.
Mine will not turn off. Came on its ,now will not turn off
Thats the first thing I noticed and wondered through the entire video if there were nothing wrong with the radio in the first place.. was all of this due to an organic interface error? Could they have saved time and money by simply reading the manual? LOL.. will never know.. but wont send my stuff to this guy for sure!
Thanks for this Peter - I have one of those inexpensive TYT handhelds, and I know if it "goes away" Ill only be out $100.... At least the owner of that radio will learn not to hook up an extension that is not made for it.
I don't have words I'll only say Outstanding video by a very very excellent teacher. I learned a lot from this video
thank you
Yes indeed, I’ve learnt much here. Was about to buy this radio. Parts are not available
I really enjoyed the value of this radio when first purchased... Unfortunately I have had 4 of them all go bad for various reasons, non of them abused in anyway and now they are just scrap radios. Won't purchase any more. Good video👍
I have the Yaesu version, still going strong but not used much anymore. I hated it in my work truck, such small fiddly knobs and buttons in a rough 4x4 truck. I was constantly knocking it of frequency or enabling wires-x accidentally. Also I couldn't tell what the volume level was set at easily. You would drive off the road trying to read the display or adjust anything. Its my spare back up radio now.
Peter is holding the (used) parts supply chain in his hand! His well educated guess about NOT using an ethernet cable to extend your face plate... priceless ! Appears to be well built, so perhaps without abuse, you might get the expected couple of decades of use out of a new one.
Great troubleshooting Peter. To bad that micro is bad. Even with a replacement you would still need factory programming. Thanks for sharing. 73
Thank you my friend
HI Buddy
Great Trouble shooting on your part... It's a shame there is no replacement . Thanks for sharing this video I almost purchased one as a 10 meter mobile radio but learned it was only FM and I was looking for Side Band mode.... Thank You again... 73's KC3ZDW
Thank you!
Thanks Peter...learned a new trick with the IPA, I've always pointed my IR thermometer (or my calibrated finger tip!) at them before. 73 - Dino KL0S
Thanks for feed back Dino! Yes the IPA method is working perfect...All the best 73
Oh the good old days you had a switch to turn the radio on and off kg6mn
Very nice video Peter anyways. We always learn something with your Videos. Really a its odd having to lose a "nice" radio because a lack of spare parts.... Thx for sharing your time with us again
pin 17 is the internal interrupt 1 grate video! I wish more people made videos like this
Great video as usual. The alcohol over-heat detection method is a good tip but I do prefer using a temperature probe!
I forget sometimes that not everybody is familiar with the notation conventions of digital electronics. The notation "INTn" where "n" is some number generally indicates an interrupt input, the bar over it means "active low". The slashes mean alternative uses. In this case, P1_7/TRAIO/INT1 and I think that's the physical pin name, one thing it could be for, and the other thing it could be for. INT1 is interrupt input 1, but it took some digging to find out what TRAIO means. It's apparently the I/O pin for Timer RA. Totally clear, right? Digging into the data sheet (hey, sometimes I read data sheets just for fun) I find that RA is just the name for one of the timers (there are also RB, RC, RD, and so forth) and it can be used as an input or an output depending on what mode the timer is in, so (without doing any more digging because I'm already late for work) I'd expect that the timer can either measure the time between input pulses or emit a pulse train or similar, and this is the pin that does that.
Without looking at the software at all, because it's not available, it seems likely that this pin would be configured to be used as an interrupt input. When you apply power to the radio, the CPU powers up, but nothing else does and it waits in a low-power mode until it receives that interrupt (due to someone pressing the button) and then the interrupt service routine would trigger the CPU to power the rest of the radio up.
Totally correct, you saved me from writing the same!
Well, the CPU is available via RS-online for about 5€ and the firmware can actually be downloaded from TYT. Of course you'd still need the equipment to flash it.
that for its own does not help ...
The Programming Cable and Fimware are available from China TYT will also supply the Firmware free of charge.
@@stevejones8665 The TYT software isn't any good and won't work in Win 10.
@@stevec5000 A lot of things don't work under windows nothing new there. Windows has always been rubbish.😊
@@stevejones8665 They don't have any firmware available just a configuration program similar to Chirp that has access to the extra features but when I try to run it I get an error.
Many of the comments here brought out noteworthy issues....like, even if you did replace the Regulator, the Zener, and the processor, it might still be useless because of information missing in the new processor. Excellent video, thanks!
I just took one in from a customer, completely dead, no lights, no fan, nothing. I found that the power input had a dead short. After downloading the diagram, I first suspected some of the capacitors. It was easy to remove two electrolytic caps, but they were not the problem. There is a zener diode, I think it was D30. It had a dead short. It is an 18 volt zener, appears to be 5 watts. The zener is in normal operation, reverse biased, so that if the 18 volts is approached, the voltage would be limited or clamped. In this case, I suspect the customer had reverse polarity, which in this case would have shorted the power supply, until something gives up, in this case, the zener shorted, saving the radio.
Jim
On a CPU “INTx” generally means “interrupt”. In this case it would be an external hardware interrupt to “wake up” the CPU from its low power “sleep” state whenever the power button is activated so that the CPU can wake up and process the event appropriately despite being asleep...or interrupt normal execution to power off the radio if it was already powered on. On CPUs interrupts can be either hardware or software defined events and they are dedicated routines that “interrupt” the normal program execution on the CPU so that the CPU can momentarily execute some dedicate code to address the event associated with the interrupt event. Hardware interrupts can also wake up a sleeping CPU in addition to triggering the execution of the code associated with the interrupt. Once the interrupt routine code has finished executing the CPU goes returns to normal program execution until the next interrupt event occurs.
Thanks for you contribution very much appreciated!
Very interesting video and diagnosis. Thank you!
45:30
We can see a purple spot on the microprocessor. Surely the frying area
yepp so it is
Great detective work! Very instructive. Thank you!
Hi Peter,
The method to determine heat with applied alcohol is so close, but I've never come up with this idea. Great, I learned something there. Thank you!
I also operate such a TYT device. Back when I bought it, I thought that I could also build this remote cable myself and thought of an Ethernet cable : -o
I found an offer with cable included while browsing and I bought this. Sure, I would also had toasted my TRX with a self-built cable.
So I learned something again .....
Thank you for your work and the video.
73 Bernd
Yes works perfect with IPA Thanks for stepping in 73
Hi Mr. Peter, and sorry for my little English. In the video you can see very well that in the beginning, you "try" to turn on the transceiver, but it doesn't even turn on. To make it turn on, however (!), You press and very briefly release the power button. Well, ....... by doing so, .... it will NEVER turn on! Because the manufacturer has provided for its ignition, that the ignition key must be "kept" "pressed" for about 4 (four) seconds, before turning on! I explain this because, owning it, on the first day of purchase I also thought it was broken, because pressing the power button, as you did in the video, it did not turn on. Then I tried to keep it pressed (instead of just pressing it as you did), and it turned on very regularly and is fully functional. Even a friend of mine, who bought it after me, called me for help because it didn't turn on ........ but as soon as I explained to him that the power button had to be kept pressed for a few seconds .... .I call back happy telling me that it worked perfectly. So ... be careful to make judgments ... before you know how a product works. Then I noticed that you try to "denigrate" the product, ... and only for pure "racism" because it is of Chinese origin ....... But here he is wrong ...... because if he has noticed the components inside ...... it is "strangely" ALL Japanese Original. And if you had better informed, rather than to show off the cheesy "racism", .. ... you would discover that, in REALITY, that Transceiver was ALL produced by the Japanese Yaesu Musen with only few very small changes ... which company then "granted" the exploitation and resale of its product, to Tytera (TYT), on lavish "payment". So .... that product is a Made in Japan product ...... "rebranded" TYT. And ... so ... it's not Chinese .... Greetings of a Happy New Year
Thank you once again, Peter, for an exceptional video. I really enjoy your fault finding techniques. You explain things in a language that I can understand. Your English is excellent. I doubt that I could follow you if this were in German. I have 2 classes in spoken German but if you don't use it every day, you tend to forget the words and sentence structure. German does have a sentence structure that translates quite well into English. Excellent video on this Chinese radio. Only Chinese radio I own is a Baofeng UV-5RE that a friend opened up to 1.25 (meter or centimeter??); anyway the 220MHz band. The tri-band antenna cost double the radio cost. A nice technique with the alcohol on the CPU--I've never seen that before. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee
Thanks Rusty, althogh I think there is room for improovemnt when it comes to my English
Great video, I would have got as far as the blown regulator, replaced it, it would have probably blown again and I would be stumped.
Same here. Total confusion after that point.
thank you for the excellent video i have the tyt-9800 but lost receive on 2 mtrs only and the advise is true due to the cost of this new the radio as been left until a long rainy day to have a look.
I have the TYT radio and I have to hold the power button for 2-3 full seconds or longer to get it to "power up". I know this video is a couple years old, but I didn't see you hold the power button for longer than a fraction of a second? Maybe hold the power button for a bit longer next time?
Belle démonstration, bien conduite et expliquée posément, le test final avec l'alcool est surprenant mais convainquant
You're right,probably the front panell it's toasted too because somebody tried to extend the panell from the body using a LAN cable,but i'm so curiouse to see that radio totally fixed...:)
I was really afraid something like that would happen :-) the technician in me is so disappointed! :-) Awesome video and I love your alcohol trick
That is how it goes :^) Thanks for watching
Excellent video! Loved the Alcohol demonstration.
Buenas noches, en primer lugar darle las gracias por este magnífico vídeo ,así como también a todos los corresponsales que han intervenido con sus comentarios, tengo una radio igual qué esa ,después de abrirla sacar la placa me encuentro con el regulador U41 en corto el diodo de 5,6V en corto la resistencia r40 de 100 homios abierta el diodo zener doble Q407 destruido y componentes por la parte de abajo de la placa justamente de bajo de U41 chamuscados también para cambiar y curiosamente hay un componente con referencia 0R según el esquema al lado del diodo D110 que esta en cortocircuito, al medirlo ,pero que parece una resistencia 0 aunque en el esquema viene como un condensador.bueno lo dicho gracias a todos cuando reciba los componente los insertaré y a ver que pasa.saludos.
Another great video Peter. I’m not familiar with this radio, but again another computer with a little radio! 73
If you make sure the extension cable you buy is straight wired, this should not happen. In this case, the right cable would be an R12 6P6C straight through, duplicating the wiring of the factory short cable that links to the head unit when it's mechanically connected to the radio body. It would have been very helpful to have the owner provide the cable he or she used so its wiring could be verified, but it seems it was not a straight through but rather was some sort of fax machine cable. Lesson learned.
Just got a used toasted TH-9800. Similar to yours, EXCEPT it blows fuses at initial power application (not via switch). We shall see...thanks, I will use what you did....
I have 2 of the same and both had to be sent back to China for repairs. There are 4 IF filters and the circuit in my view is bad. They had to be sent back to China 2 times for the same issue
this rig had a blownn final i had a good on from my ft991 and it worked in this rig cool haa kg6mn
i OWN THIS RADIO, IT WILL NOT TURN ON WITH A SHORT TAP !!! PROPER TURN ON IS TO HOLD POWER BUTTON AT LEAST 1 SECOND. The radio is a huge success in my mobile ARES vehicle. 73 - KV4WM, a US Navy Nuclear Submarine Veteran.
Honestly i'm surprised you found service information on these. I hear that can be tricky sometimes.
Your video started off similar to my experience, I do not have 13 volts at FB on the front connector. I have a known good radio that does have FB present when power is off. So it is mislabeled as SBE. I cannot figure out why it's not getting power at FB on the connector side. I jumped it temporarily and chip u118 started to get hot. That is my next culprite
I had the same thing happen with the same radio brought to me. Luckily, I had another 9800 with a burned pcb that I was able to swap out the cpu and diode. I up-rated the regulator, feeling this is a vulnerable part. What a shame it is a death and TYT not being close to hand. Might be worth a try contacting them, but hey-ho, these radios are cheap enough. Thank you for the tip: re the Ethernet cable. This would not have ocurred to me.
Sorry to see the radio having to be scrapped.
TRX - you have had two tough dog repairs, good troubleshooting, the Zener 5.6v couldn't save the main CPU....Happy Easter...Hugh..Chicago..metro
Happy Easter and best wishes to Chicago!
could u design the am tx section which was removed, but barren patch of circuit board is there and ready. Sorry to hear the radio is kaput.
Great video Peter easy to understand your trouble shooting :-) 73 James
Thanks you James! 73
Right at the start I noticed that you weren't pressing the power button long enough... 1-2 seconds.
I have the same issue with cheap Chinese UHF CB (Australian 477 MHz band) radios. They are just so cheap that it's not even worth replacing a shorted zener diode on the input supply leads.
Wow! Some big detective work there! Nice...can you blow these radios trying to wire a microphone to?
I want to wire Yaesu MD 100 mic..
Disposable item and priced as such - I have several - if they break I replace them.
must be nice
@@jeromegrzelak8236 No. Back 10 years ago when the CCR's were rumored to be hitting the market, the ham radio community raved about how cheap they would be to buy and how they would be a "throw away radio". Well, CCR's are here and you need to own up to the ranting about how they are throw away radios. Throw them away. Stop flooding the internet with this garbage about fixing a $30 CCR handheld. Even the MFG's who make this crap don't fix them because the cost for shipping alone often is more than the value of the radio.
@@jeromegrzelak8236 at that price ..yeah.. it is.. it's good to maintain skills in repairing electronics though.
hi peter where can i get the schematic and the other service manual information that you are using as my th9800 as developed a problem with the 2 mtrs band no recieve. thanks for any information you could help me with
Some days you get the dough nut other days you get the hole :-) Happy Easter Peter.
lol. Happy Easter OJ
Thanks Peter! A thin layer of Rodico will help in testing tiny components.
Thanks for feed back Robert but what is Rodico??
Watchmaker's putty. It has many great uses. Get yourself a stick of it. And if you are not happy with it, I'll give you your money back. Besides cleaning my tweezers and screwdriver tips, I spread a thin layer of it to help keep tiny components from moving and hopping around when I am trying to test them.
I got this radio as my first non-HT. 10meter and 6 meter FM are very interesting! Mine is the "Improved" version whatever that means....I've run it through a lot, including cross band use and it handles it like a champ but I do worry about running it on high power. I definitely don't get 50watts on it unless I am on a 25amp+ power supply.....30watts on high power is the best I get on a 12amp PSU.
It requires a 15amp power supply for full output.
I suggest you remove the pcb and fan. Drill out the back of the case to allow the air to flow internally over the PA and the pcb, then drill three slots in the lid as an outflow for the hot air. You can then run high power knowing you will not blow up the radio's PA. You learn these tricks as you go along life's ham radio highway. Also change out the regulators for the 1.5A (TO220 type) and heat sink them using thermal compound. Long life will ensue. Happy days.
Are the parts any different from Yaesu FT-8900? It’s either a clone, or the exact same radio as that.
Its a poor quality clone , I opened my FT 8900 just to verify it.
Notwithstanding the fault, this radio needs the power button to be held in for a second or two before power will be applied. Quickly pressing the button as shown in this video will not power up the radio even when it is working. Otherwise, thanks :-)
Cracking video Pete.
What makes these older ham radios give out that varying tone when your close to dialing in? 27:13
D30 is not only for polarity protection. D30 for overvoltage protection and polarity protection
if it is truly a zener diode that is right.
Great Video on troubleshooting.
Thank you for your videos. I enjoy and learn from them. 73 de KO4Z
also I purchased a warranty with the radio and have used it once, parts are available and it can be fixed. Otherwise in the last two years it has been issue free and I constantly get positive comments on how good the radio sounds.
as long you are happy all is fine
Are you sure they didn't just replace the radio?
@@dayjeremy Yes, they sent a note stating that is was repaired.
Can't win them all Peter, enjoyed the video.
I have one of these radios it came to me from China with two bulged chips that looked like they where heatguned to death. It has not failed me so far. And I use it as an everyday beater in my Lincoln
I have had it for over 3 years now. Works ok as a gmrs radio on my mfj night rider antenna. I know the mfj nr antenna is really for the70cm and 2 meater ham band but it's a good enough swr and vswr for my needs. I have a 1.1>2 on 2 meters and a 1.1>3 on 70 cm and a 1.2>4 on 462-467 mhz ehh it's a Chinese radio iam not going to bother to put an antenna switcher and multiple antennas on my car. As it is the tweakers here think I have a cb am radio. And I get tired of explaining to everybody that asks that it's a ham radio Chinese knock off of a yeasu 8900 quad band Usealley by this time I get a funny look on there face.
great work as always,,thank you for you great videos
I had bought one and connected it to my bench power supply. Ran it for 15 minutes and then connected a watt meter with no problems with a quick transmit. I let it sit just to receive for about two hours then it quit. The display goes dead, the radio starts pulling more current. Shipped it back and bought a Yeasu instead and have had zero problems with it. It's a hit and miss with these radios the quality control is lacking.
and the company don't care!! You are right buying a Yaesu 73
I think J114 is for the front panel display panel, I need to know what the pin-outs are for the mike!!, please see the next comment I left
for you, tnx.
comment
Hello i have to replace the diode on this radio it keeps blowing up the fuse what diode does this radio use..?????
Nice trick with the alcohol, But i prefer to drink it :-)
LOL but you won't drink IPA :^)
If it was free i might lol@@TRXLab
The diode was not effective maybe a little slow and not efficient I think it lacked a small current limitation in it, excellent video hugs from Brazil Peter.
More likely, just too much sustained current as a Zener is quite fast at clamping, but you still have the issue of impedance limiting its ability to protect if overwhelmed by current. That said, the Zener was almost certainly selected to provide ESD protection since it leads to an external jack rather than a sustained over-voltage event from getting the connections swapped. Ideally TYT would never have sent unlimited 13.8VDC direct to the front panel through that connector. If they had limited the front panel to 5VDC then the swapped connections would have remained within the safe 5V limit the CPU could handle and no serious harm would have been done so long as the resulting current was not sufficient to burn through PCB traces.
On the Yaesu FT-8900 that this radio is supposed to be a “functional” clone of, the front panel voltage is provided by way of an 8V linear regulator which should have then gone into overcurrent protection upon shorting of the Zener and would have likely then protected the radio - Yaesu did not just pass 13.8VDC straight through to the front panel. I’ve not studied their schematic for the head unit port, but I would hope Yaesu implemented better overall protection for that port (and strongly suspect they have, not that I’m going to intentionally short out either of my FT-8900 front panel interfaces just to test that hypothesis!).
You are right it was not effective enough for 13,8volt.. Thanks for feed back
Again, very nice video, the alcohol test was a new one for me. What a shame, I was really hoping to see you replace the CPU, however like you said, more IC’s also could have shorted from the high voltage getting through the shorted Zener.
Would have been interesting to see if the removal of the vcc +5v power pin of cpu, or complete removal, would have lifted the short on the 5v line. If so, maybe all it needs then is a new CPU “if can be found somewhere” and new Zener Diode?
Well it is no problem to get the uP it is only 5$..the software is the problem...
TRX Bench
Ah, I see. So the cpu has custom code to operate, and the eeprom only retains the user’s settings ?
I thought the power button requires holding it a couple of seconds.
Thank you for another great video!
I have an issue with mine. Right side had bad receive on both bands (2/70) and does not transmit audio, just carrier and you can hear dtmf tones. Left side the same but receive is ok on 2m/70 cm. I can also transmit and receive on 10m and 6m on the left. Any ideas where to focus?
nothing wrong with it jus push the power button in for 2 seconds and ready ...how u do it it wil not go on or of..
Hello Mr. Peter's okay, it's been a long time since you made videos.
Greetings from Naples.
Paolo Di Masi
Great video. Thank you
same here power on the issue. it always on.
Hello, my question is because the vfo does not give the same signa
Why a thumbs down? You don't get it? Nice job Peter.
Thank you Glenn.
I've had good luck with UTSource for parts like this. They will research it and let you know. You probably will need to register for an account.
Thanks for the hint will try it out. Where is UT Source located?
Not economically feasable to pay for repairs on a robot built radio, only parts will come from another dead radio. I own one I have never taken out of the box. Wont use it where my my life depends on it.. that's for sure. BTW this is a clone of the Yaseu FT 8900.
Do you keep a database of problems, parts and models? A troubleshooting database of findings? A nice product to sell.
in my mind only
plus labor + parts to much buy another chinese radio good job sr thanks terrific video thanks 73
Didn't know The Young Turks branched out into ham stuff.
I wonder why the sellers of this model radio are making false claims about it saying that it can receive a wide range of: 26-33Mhz, 47-54 MHz, 110-180Mhz ( with AM Air band), 350-399Mhz, 430-512Mhz, and 750-947Mhz? That's not true, it can only get 4 Ham bands. I was thinking of buying one until I tried it and found that it doesn't get the frequencies they claim.
Frequency range supported can depend on country of import. For example, in U.S., the FCC (Federal Communications Commission) requires amateur radios to be limited regards transmit frequency range in each of the bands, to prevent out-of-band use. Imported to Australia, the programming would be different.I think there are work-arounds; a little Internet searching will answer that for you. KI7ZEI
@@timhaupt5270 That's not true when you buy it on Ebay coming from China. The receive frequency is also limited to 29/50/144/430 Mhz. and there is no work around. It's odd that all the sellers still claim a wide frequency range but they seem to just be copying bad information from the TYT website.
steve c wow
Peter I recently purchased the tyt th9800. Wondering if you have experienced the radio not turning off. Out of the blue decided to turn on its own, now unable to turn it off, holding down the power button nothing. Unhook the power goes off ,wait a few plug-in the power it turns on with out pushing the power button. What do u think