#68 Yaesu FT 747 No receive diagnose and repair
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- Опубліковано 2 вер 2016
- In this video we have a look at why a FT-747 has no receive on any band.
After the repair we find that SSB has distorted sound and then we inspect for the cause.
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I have been watching a lot of your videos from the past and find them quite enlightening. I am just a beginner and getting into restorations of old radios and test equipment. So much to learn... Your videos are an inspiration to me.
I love the way that you make your own specialized tools. That’s so ingenious. Thanks for the fun Buddy 👍
Those are nice radios. I had one about 12 or 13 years ago and sold it when I got out of the hobby. Sold off all my gear back then. Just this past September I got back into the hobby, and I purchased a Yaesu FT-757gx, which I have emailed you about, as well as the matching power supply/speaker unit and the matching auto tuner. I have always been a fan of the Yaesu models. My very first rig was a Yaesu FT-840 and I loved that radio. I have had a Yaesu FT-101E as well. Great video and very informative. 73 Juddie WD8WV
Nice work and very well documented. Thanks for taking the time to do the video! And try to stay safe in that storm!
Thanks for the nice comment. I love doing them. Storm has past and all is well.
Your welcome buddy, 1 of the reasons I enjoy your repair videos so much is that there are no airs & graces, just honest repairs explained in plain English.
Appreciate that.
Buddy, another great video, thanks! I'm starting to get into radio repair myself, and I'm learning tons from you and others. I also have an IRF on my bench. I enjoy seeing another bench that does NOT have $100,000 in test gear on it! It gives me hope that I can do repairs without breaking the bank! Good luck on the flood repairs! - Mike / KD2EAT
This repair was a nice trip down memory lane for me.
Thirty years ago I had an Icom IC 745 go deaf on me suddenly. The radio was bought new. I can remember paying 745 dollars for it too. Anyway, as with every radio I purchased, I always got a service manual for it.
Now time does play tricks with one's memory but I seem to recall it went deaf on the broadcast band and 160 but the higher bands were FB. So I broke out the service manual and started looking at the schematic from the antenna onwards. I saw a light bulb in the antenna circuit. So I opened the radio up and went to the board that had the bulb and sure as the sun shines, the bulb was black. I jumped the bulb with a short wire and the broadcast band and 160 came back.
I knew the bulb was a protection device, so I replaced it with another one like you did in this video. In my case I started at the antenna when I diagnosed my problem and found the condition right away. I know you have a 745 too and are probably aware of the bulb protection circuit in it. If convenient to your experience, was the bulb in my 745 exclusive to the broadcast band and 160? I seem to recall it was.
This is an excellent video and for ham radios of these vintage years, looking for that little bulb being blown out can be the answer for many repair possibilities.
Thank you for sharing this repair with us.
Thanks for that awesome story! Like you I do believe the bulb is in the lower portion of the band circuit. Think this is where the problem originates the most.Thanks again for sharing and for watching.
I do have 747 that worked well until recently.I do wish I can find someone with your experience and knowledge to do the repairs.The challenge is I am 6000 miles from you. Very instructive video.
Love those easy fixes! I had a 747 and used it in our motorhome as a mobile for many years; loved the "click" on the VFO knob but hated the thick cable used to remote the front panel up on the "dog house" of the RV. Although I understand the need for those darned TMP connectors in terms of space considerations on the PCB I always hate messing with them! Have a nice holiday weekend Buddy. 73 - Dino KL0S
Easy is always a good thing! These do make nice radios for the RV. I also hate those connectors. The clicking knob is very interesting and is smooth for on the road tuning. Have a great holiday yourself my friend and thanks for stopping in.
Ótimo eguipamento perfeito parabéns guerreiros bazuka Foz do Iguaçu pr Brasil
Great job buddy! Nice to see the old 747 happy again. I like the pen and toothpick tool idea. I can't count how many plastic tools I have gone through.
Thanks Paul. I have been doing that method with toothpicks for many years. Some of them are a bit too soft. To solve that put a drop of CA (super glue) on the tip and wipe off. This hardens the tip. Yes the 747 is a happy unit and hope it will be in service many more years. Thanks for stopping in my friend.
What, it's not happy? That must be a typo :^)
oops. Yep typo. Don't know why I put a "not" in there lol. Thanks Paul. Fixed :-)
Great tutorial Buddy!
I am about to start on a Heathkit SB1400 clone and hope I can get it fixed!
Congratulations, another cracking repair.
Thanks Andy. I do like to easy ones :)
it's nice to have a easy repair every now end then nice video mate big thumbs up
Thanks allan, the easy are nice to get.
nice work again,, those are my kind of repairs,, Thanks Buddy
Thanks Dennis and glad you liked it. Sure is nice to get simple stuff to work on.
Just found and subscribed to your channel yesterday, and funny enough my first HF radio is an FT-747. Although it's pretty used and tired it does receive and transmit pretty well, i dont have the equipment to do it but it could probably use an alignment.
But my main issue is that most of the front panel buttons are worn out and im trying to find good replacements, im comfortable with soldering new ones in, just need to find ones that will line up right on the PCB, I should probably make a few posts in some ham radio forums online. Ill probably change the bulbs in the front for the LCD screen while im at it.
Thanks for making these video's, they are really helpful.
When you say worn out you mean the switches? Sometimes you can take them apart and clean them and they work pretty good. Keep an eye on ebay and you will find pulls quite often. If no one has gone in and really turned everything the alignment can be done with little equipment or cheaper equipment. Yes post about it on a few forums and someone may have the parts needed. Thanks for subscribing.
Very interesting, the concept of visual inspection and systems check is starting to sink in for me. You have got my attention. One topic that I would like to see you expand upon is schematic reading. I know you do a lot of that with your presentation, please do more.
At times your own senses is better than test gear. I will provide more schematic reading in future videos. With all the stuff out there these days that do not have schematics I like showing the ways around without them at time. Thanks for commenting my friend.
Well done mate i have a couple of the 747s and really like them...Thanks for video
Thanks for watching. Good little radios.
Thank you. Very useful info.
Thanks
Thankyou,for teacing us.
Thank you
Great video very educational
Thanks
hey congratulations
great job and whatta beautiful radio mint condition.
Thank you my friend
Great tip on improvised tuning tool, toothpicks!
Simple and gets the job done :) Thanks for watching.
Cheers I like the common sense approach ... not everything needs to be too difficult!
More like this...Ta!!
Thank you, I feel the same way.
Nice Work....
Thanks MrMac. Always a pleasure to see you.
Nice repair Buddy. THanks for the videos :)
Thank you Grant. BTW, may call you this coming week.
Yes call any time :)
Will do. Maybe tomorrow.
May most of your fixes always be simple ones!
Worked on a Palomar 500 CB radio that I believe had an indirect strike and a bad receiver. Had to go thru the entire receiver circuit one component at a time, but I fixed it. It was an unusual type of part failures. Two transistors and two diodes were found to be leaky. Now I can understand ONE of those parts going bad. But the fact that they were leaky and not open or shorted was strange. That - and the fact that four devices had failed nearly simultaneously led me to the conclusion that it had to be a nearby static crash. Your thoughts, Buddy?
Hi, Very informative videos. I have a Yaesu FT-7B with the same issue and trying to find a source for this blown lamp and was wondering what range of in volts and milliamps lamps that would work for this. Thanks.
Yes Buddy its nice to have a few of these kind of repairs in between the bad ones or needed $$$ for those repairs costly sorta balances things out.So yes enjoyed it and followed thru very well, yes saw the Burnt spot on the blub .Thanks for your Efforts Buddy 73's PS you keep that line noise down there gee havens how you put up with that,Bet you can tell which radio has the best front end rejection lol lol
Thanks Dale. Sometimes the bulb looks burnt but is a coating inside them. Was thinking the bulb the whole time but wanted to show the full analysis of the repair. Thanks for watching.
Hi..really enjoy these videos. i am working on an old transceiver and looking to get hold of some bulb fuses. i am in Ireland
Thanks James. Can you get ebay there?
Yes i can get ebay. I looked on there maybe not in the right places
I have one of these radios that I am now trying to repair on my own and I had a couple questions. One being how to take off the face place and remove that circuit board, and the second being where to get a replacement bulb as mine is also burned out it seems. Thank you, KD8TAE
Thanks again for the good videos .
Might I suggest that when you are letting us hear a signal / noise , you keep the audio of what ever signal , lower than your voice ;)
Having to turn down the volume at this end , I miss what your saying , again thanks John
John, thanks for the feedback my friend. Lets see if I can explain this a bit. My camera has no external mic jack and is a bit sensitive. So you are hearing this just as I am. If I turn the volume down then trying to get a sinad reading would be impossible. :( I am currently building a audio dummy load. When this is complete you will not even hear the tone so that will keep the noise down. Wish I had the 1200 bucks for a new cam but not going to happen. I will take this into consideration on the next video. Again, I appreciate feedback like this.
The bulb is a nice technique. Might make more sense if it were on the outside, and easily changeable without soldering, but I suppose this doesn't happen very frequently. Thanks for another video.
I agree. The older rigs had the bulb in the back with easy access to it. They decided to put it on the circuit board in these rigs. Now they seldom go bad is the plus. But good to have this feature. Thanks for watching.
tnx 4 the video
Thanks for watching Henk.
I have the Heath SB-1400 version of this radio, and the AGC/NB circuit just went out, I'm curious if they are both driven off the transistor on the board right next to their switches.
awesome
great video! I have a question. Im just getting into ham and have done a ton of research into what radio to get. i think im going to get a 757gx. it seems to have most of the good stuff all in one. my question is in your experience is it a good reliable choice? i am moderately skilled at electronics repair and have the basic tools such as scope spectrum analyzer etc. and am not afraid to fix it if it breaks as long as parts are available etc. your opinion would be valued and appreciated!
The 757 is a great rig. I really like them. And are fairly easy to work on. But. things that go wrong are the diodes on the RF board. Then there is Catastrophic failure of your CPU which is no longer available. Even if it was there are no programs or information to program the chip. Other than that. Good rig.
Bravo! Another happy customer. Good video, liked the tooth pick idea. Just returned from Shelby with a few goodies to work on this winter, great day, for me. You were on the roof. :>( "sorry" 73
Thanks Larry. Sometimes simple things like a toothpick is all it takes. Would have loved to went to Shelby. Have not been in a long time. Like to hear your future projects you have. And yes, was on the roof lol....Thanks for the comment my friend.
Yes Shelby is likely the last one for me this year, so I needed something for the winter to keep me busy. So I picked up a 350, 700CX, and a 117XC power supply (Swan) all for a very good price I thought. They need
some work and a good home. Their only 50 + years old, it will be fun. Hope you have Monday off to relax. 73
Thanks for all the great videos. Just wondering, which manufacturers make the best marine radios, in your opinion? Have a great holiday weekend.
Thanks for watching. I take it you are talking about VHF marine. Then that would be Garmin, Icom or Standard Horizon.
nice one Buddy we like those easy ones made a good video tho.
Thanks Gary. Easy ones make quick videos.
Buddy, awesome video, I look forward to them, I have learned so much from you, Peter, Allen and Mike; the big dogs. I do have a question, that internal connector that came loose, what is it's name and where do you buy them? On advice from Peter, I have the need to inject a signal into that type of connector but I need to convert in from an N connector (or other more common RF type) to whatever that is. Any ways awesome video please keep them coming.
Thanks for the kind words Michael. Don't forget Paul at Mr Carlsons Lab :-)Those connectors are called TMP connectors. These are fairly cheap. But the tool to crimp them are about a grand new.....See this link for source.gokarters.com/smf/index.php?topic=2602.new#new
Saludos amigo, tengo un FT80C (747gx) con el inconveniente que al presionar el boton de power no enciende al principio no da Tx ni Rx hasta al buen rato que creo que calienta algo o cuando le doy un toque (golpe) ligero , es que empieza a dar (RX), y (TX)
es el unico problema por ahora... quisiera que me ayudaras al respecto, ya no doy mas con ese problema...Gracias por el aporte..
I'd say your a pretty bright bulb yourself there Buddy.
Appreciate the comment.
its not bulb.. its bub..
Very nice repair Buddy! Always this lamps...sometimes to slow for fast transients but other than that they blow hihi. 73
Hi Peter. Thanks for the comment. So good to see you my friend. Waiting on your next video :)
thanks Buddy, yeah just back from holidays... Take care!
Really hope you had a great holiday my friend. 73
What does a leak on the roof have to do with this radio
Yes buddy call any time :)
Good afternoon. I have an FT747gx that I operate in digital mode, via RTS. Can you tell me where I can find the CAT cable?
I have a Yaesu FT-747GX And at AM Mode, it sounds terrible. That's the report from everybody side bands work good.pace directly through your page and I read that you do not work full time that your work would be very calm and slow, but yes, with success I would like to make contact with You let me know if you are willing to work on my Yaesu FT-747GX Thank you.
Hi ! I'am having this rig and need to open the front panel for repairs. The MODE / VFO MR and such buttons are not working properly. Can you please share with me how to open the front panel of this YAESU FT 747 GX. Thanks.
Well that was a fairly easy one. Looks like we both have deaf radios to fix. Got a new old stock Royce 1-641 that can barely hear at 10mV/-27dbm. No light bulb protectors here. :( Good luck with your leak.
Hey mike. Yep wish they all was this easy. Loved the old Royce units. Maybe not to bad on you.Roof is all fixed and no more leak. Even feel better :)Thanks for watching.
+The Radio Shop
Glad you found your hole. Looks like I'm having PLL sardine can output problems with the Royce. Very low input to the first mixer.
That should not be too bad to track down. Used to love working on those sardine cans. Also makes for a nice signal generator source.
+The Radio Shop
LOL, I have piles of sardine can PLL's here from different radios. They do make nice signal generators. The ones out of the Cobra 77X radios used a upd858 and could be fairly easily retrofitted into some 23 channel radios to update them for 40 channels.
YEP got to watch those Breeze Floppers.
LOL
great video.Nice clean radio.73 kn4u
Thank you.
I have a 747 receives beautiful... But won't transmit have any idea who may be able to repair it?
Got a solar farm there? What state/province are you in?
On the east coast of North Carolina. Yep these solar farms are popping up everywhere and bringing in a lot of noise.
Buddy,
Don't you wish all repairs were as easy? Nice repair video.
WB3BJU
Hi Donald. We could only wish my friend. The owner thought it was going to be a tough one I think. The easy ones like this sure brighten the day :-)
Could some one help me please.my Ft 747 GX drifts on RX and TX if I tune the V/cap on the side PC Board and replace it and the 3 for USB LSB AM will work fine then it start its same old story again Regard's Keith.ZS6KAS.
You will need to replace those plastic VCO trimmers on the rear board with good ceramic ones.
i have a heathkit sb 1400 that needs repairs.
mine was a rats nest inside no dsp u got to have more than 12.4 vdc or the radio turns off
I am not sure why you would jump way ahead in a recover and start adjusting slugs without first doing a visual and then a simple continuity test on a known item that is in circuit for this very reason. I am only making the point as I am trying to learn and the approach in this video seemed like a maverick approach not one using your normal logical thinking. Still love your videos.
Also not sure what you have the voltmeter connected to. I am assuming the audio output of the rig. Thanks
Hi Kevin. Appreciate the feed back. Let me see if I can help with a little logic on this. I have worked on dozens of these 747 over the years. Seen about everything you can think of to bad relay, blown bulb, bad RF amp. Just about every time I get one of these I find those 3 IF cans are misadjusted. Even had 2 of them in the shop that had very little receive only to find that the cans were adjusted incorrectly. You have to watch out for the golden screwdriver operators out there. Out of all of these I have worked on this is the third one with a blown bulb. As far as the volt meter it is connected to a 8 ohm dummy load that is plugged in the rear of the unit.Thanks again for the feed back.
+The Radio Shop Thanks a million. Just seemed to be out of character for the way you go about doing things especially when you are doing such great training videos. Again thumbs up just wanting to keep learning. Have a great evening and keep your wonderful work coming
When it was as deaf as it was I'd have gone right for the relay or bulb first.
The tuning of those if transformers wouldn't knock it out that far (60+ db) unless someone had been in there with the old golden screwdriver.
I agree, But with all those golden screwdrivers out there I wanted to show what to look for. I get a lot of ebay specials where folks try and squeeze every watt out of the rigs. They see those cans and must turn them. Thanks for your comment.
this rig had a heathkit logo on some models dont u love it when the fan comes on man kg6mn
Did not know about the heathkit logo on some. Very interesting.
But if you weren't good at what you do, it wouldn't have been easy.
Thanks for that very nice comment Andy! I am no ways good as a lot of other fellows I have met. Some of them blow me away. But I do have a goal. And that is to make repair videos in a way to help others learn using basic test gear and plain English so everyone can understand. Without getting all techno on them. I have received many emails where folks have fixed their gear by watching my videos. Some have not even held a soldering iron before. Thanks for watching my friend.