Some Faults You Cant' Fix Because You Can't Work Out What Is Wrong
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- Опубліковано 25 лип 2024
- There are some thing I can't repair because I cant' work out what is wrong.
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Thank you
Richard
Thanks for your work. I am a bit disappointed that it cant be repaired. Lot of digital things are not possible to fixed.
Thanks for all from Sweden.
I don’t get to comment very often at all because I watch you on Roku on my tv at the work bench. Just want to let you know I love your videos! I’ve watched probably all of them more than 2 or 3 times. You do a great job at explaining things and letting us watch the full testing. I love the longer videos when you get really involved or diagnose all the chargers or just whatever. I’ve learned a lot from you! I’m a hobbiest at this stuff but I do have the tools. So thanks again from Long Island NY!
It seems you're one of the million viewers attracted to lengthy videos. Typically, viewers come, quickly check to find what interests them, and then move on, never to return. At least in my case, it seems to be the common scenario on my channel.
This reminds me of a time when we were called to figure out why the emergency lighting pack wasn't working. My (former) boss said the pack was faulty and needs to be replaced after he diagnosed it. We checked and long story short, the lighting pack wasn't even connected to the mains. Client was happy when my partner did the connection (he was an electrician), the battery was replaced and the problem was solved.
My (former) boss, wasn't too happy as he was hoping to charge even more.
I've learned so much from this video. You've wonderfully showed a variety of approached to fault finding in this one video. Keep it up.
Thank you for the great video's, I'm a beginner when it comes to electronics and your channel has been very helpful. I was wondering if you had a list of useful components that would be useful for starting out? more for testing and understanding. Thanks for the great advice and tuition.
The main S905X2 chip on this is a Quad-core ARM Cortex-A53-based SoC with a Mali-G31 GPU. With any board containing a CPU the first 2 things to check are clock and reset. You tested only the clock. If you had 2 of these you could simply swap the big chips over (SoC, DRAM and Skyhigh ROM). That should get it going. If swapping all 3 over one by one doesn't fix it at least you have narrowed it down to one of the other tiny components. However if these are commonly failing and you are seeing a lot of them you could invest in equipment to backup the ROM and then you can buy a new ROM and re-flash it yourself using an eprom programmer and the BGA adapter. The problem with this thing is it's just an Android TV box. They are common as dirt and can be replaced for less than $50 and your time already spent on this job is more than that. Probably better to tell the customer to buy another box and move on.
Yeah I was thinking that, gotta be worth finding the reset circuit for the soc and checking that!
This is not your common Chinese Android TV box, it's Ukranian Mag middleware box with probably something like Stalker installed, not Android. And it costs $100+
I love watching you try to fix things. I love that it's real life. I don't think I would trust an edited video where everything worked perfectly and everything got fixed.
things like this is very hard to troubleshoot without acces to spares/spare parts/schematics, but you gave it a fair chance with whats available to you
A cheap AM/FM radio tuned so it hears the noise of computer clocks and the bus is more likely to catch any changes in the boot sequence of something that appears to be bricked than anything I know of.
That's an interesting idea, I'll play around with that sometime 😁
I used one to track & debug embedded systems and it saved a lot of time.
I’ve been practicing fixing on a faulty pi, I’ve come across a lot of shorted caps heading to the processor but it’s not that because the shorts still there after removing so I’m going to call it a day for that
Well,... This repair was kind of interesting in the sense that sometimes you are limited on what you can repair with a device like this especially when it might involve programming... What I liked was the discussion of the possibilities that could make this device not work and make it not something that can be repaired without specialized equipment. Since we kind of poke around exploring the board and some of the voltages of things, I was a little curious as to why not see if the LED gets any kind of power. This is of course assuming that it was a type of visible LED that indicates that there is power. But even with that assumption there may be other conditions that need to be active in order to have the LED light go on. Anyways I did enjoy the discussion about the possibilities of what's going on here. P.S. I have an idea for something you could show us for a very common repair and your technique and that would be repairing the wire that goes to the connector, you commented that someone repaired one of those power supplies and did a poor job, maybe if the opportunity arises you could show us a method for repair ? I know there are probably many ways, but sharing your technique could help someone who hasn't seen something repaired that way. Even if you repair it in a somewhat common fashion, someone may not have seen how to do it where you make a nice repair. Anyways, I think you know what I'm getting at and if the opportunity arises it would be something to share with the audience.
greetings from Slovakia....briliant as usually
Tiež si ho fičím 😀 ten britsky prizvuk je bozsky.
@@morvayka tak mne britsky prizvuk lezie na nervy, zaujima ma skor obsah a on to popisuje taj britsky - jednoducho :D . Ty sa zaujimas o elektroniku,ci len prizvuk?
I would check the EEPROM chip to see if the 1.8v is there, then I would use an oscilloscope and see if any data is being produced on start up.failing that I think it would be a corrupt Eprom chip.
I didn't spot an Eprom chip, maybe I missed it. We do know the 1.8V is present
VT4 Transient supressor for the USB data lines.
Is the voltage for the IR receiver present? You can boot this box in u-boot mode and upload the software after checking there's serial communication. It is described in the manual. Also on page 40 of the datasheet of the main chip the power up sequence is described. You need many different supplies, not just one.
hi kris, I know how to get into the engineers menu (hold menu key down on remote while powering up) and upload firmware from USB but you need the box to start first, which this one won't. If you know any other way to do that let me know please.
Flowers.Lol.
chocolate shoes works pretty well too 😆
G,day from Sydney Australia.
Following the examination with the thermal imaging camera, I would expect some 'glow' around the MOSFETs they were cold green with 5v
So you would have to locate the identical MOSFETs and change?
This could cost more than replacement.
(Thank you for the tutorial)
🌏🇭🇲
At 22.16 just after relesing the reset button the current draw on the power supply showed 1.4A for split second before falling back to the standby current. I suspect there may be a shorted capacitor somewhere on the board. Perhaps checking the caps for a short might be a way forward.
It was 0.14A
Nicely detected: so "some" energy is in the caps.
🔋💫
Check the on button works....cheers.
Did you try to turn it on with the actual remote control? you could also do a test to see if the LED indicator is still working too. to me it looks like it is still in a permanent stand by mode as it is now. so the signal to turn it on might not be coming through
When I reflow I give stuff a little nudge to see if it’s melted
Have you ever tried to repair the cricut vinyl cutter's red light of death? I am having the same issue where everything looks fine and voltages are there. But does not work.
I was wondering whether it would be possible to test the big chips one at a time on the board by bringing them alive through voltage injection (power, clock, reset) and see how much current each chip is drawing. Maybe that can be a rather quick and low cost solution to spot a dead chip.
Heya, the small it gets the more difficult the repair gone be
At 16:40 I got a bit intrigued why you push the chips. Is it because it (for the time being) fixes any bad connection to the pins? Then reflowing seems like the next step. Everything in this video seems to me to follow a logical sequence, and I learnt a bit of troubleshooting with this. Thanks for this one, and all the others. A fountain of fun and wisdom, Richard. Cheers.
Is there maybe a way to put it into firmware mode by shorting pins on the firmware flash chip. I know you could do that with previous boxes. Failing that, maybe a firmware chip swap with another box running the same hardware, dunno!
Of all numbers the 7-digit segment display shows on the bench power supply. Maybe see if you can find a schematic on the chips and see if there is VCC, ground, data signals, etc. That is if the points are easy to find and accessible like you were saying. Without documentation, it's near impossible and if it is, probably not worth the time reverse engineering.
I’m in that problem right now. Got a 24V supply fuse on a spindle drive that keeps blowing and can’t find the short yet. Found a spot on the board with the lowest resistance but its still 3.96K ohms
No short yet, and blows as soon as the power it turned on to it. 3.2A fast blow fuse.
I just wish i had more tools then just a basic digital volt meter.
Build the 1$ short finder on this channel ??
is it possible this has a serial interface ? maybe its spitting out some boot errors due to corrupted FW
Well there are times when dead is just plain dead.
And replacing the dead chip is the only way, but how you locate the dead chip in an embedded system is very hard. it could be the microcontroller, the flash, or one of the other chips. Without a schematic you have one hand tied behind you back before you even start.
Just put it in the beyond economical repair pile.
Imagine the front LED was busted and simply opened the whole circuit
I would try to flash the box like to me it is bricked. But by reflow tou didn't tap the chips how do you know that the chips correctly reflow.
To reflash you need to hold in the menu key on the remote while powering it up. But it will not start. I also believe it is possible using JTAG but I don't know how to do it on these boxes. Regards reflow and tapping chips, I used a thermo couple and a bit of prior experience to know when the solder is melted because I usually rap them a bit too hard lol 😅
@@LearnElectronicsRepair ok just wonder that
@LearnElectronicsRepair I have a GTX 1050 Graphics Card that will not Display. I troubleshot the issue to the Vram rail on the card. I have all my other voltages 12v, 5v, 3.3v, 1.8v Pex, 0.81v Vcore. My problem is Vram had a short to ground and when I turned on power it was only showing .04v. I removed the inductor to separate the circuit from the Mosfet and I still had a short to ground on the Memory side of the circuit. I injected about .9v ramping up to 3 amps slowly but I could not find the component that was short, nothing was heating up. Any ideas at this point?
You could just drop a Raspberry Pi in place of one of these things. Although I'm sure it's not that easy on the software side of things.
Reflow ram!
Did I miss it or you haven't tested any caps and diodes? If so, may I ask why?
All the power rails are up so I expect things like diodes to be OK and it's unlikely to have shorted caps as the current drawn from the PSU is much lower than normal. It should be about 700mA on a good one, this is about 70mA. There could be some shorted component on or near the Ethernet or USB connectors that prevent the CPU from booting maybe. I didn't show in the video but the connectors all look good.
I'd say for what they cost it's not worth your time to even open it in a repair shop setting.
As others have mentioned flashing it sounds feesable if you have the right software for the right board revision. Finding that software alone takes more time than allowed if your trying to turn a profit.
Do logic probes ever work to trip things high or low on various components to override their current state? I haven't seen you use one in these videos so far.
To flash it you hold the menu key in on the remote while powering up. This then takes you to an engineers menu where you have various options which include flashing by USB. I do have the firmware but you need the box to start to do it. The other way to at least do a full reset is to hold in the button on the box as I demonstrated. You would think these are cheap easily available boxes. At the moment I can't get any, the official Spain distributor has none, and this is mostly due to the maker Infomir being a Ukrainian company based in Odesa, If you look on ebay, used ones are selling for £100 and new ones are like hens teeth.
@@LearnElectronicsRepair It's amazing how the globalists have managed to isolate our various countries with cookies installed on our computers. When the Internet first started expanding I could easily get to other countries websites and they were oblivious to where their visitors were from. Granted there was often a language barrier but I could still get there.
I could find things on their EBay sites that just didn't show up with my searches here on my American EBay and the prices were very different.
Now I am almost locked out of these foreign countries and if I do get in I get a watered down website with prices these globalists feel is right for my particular country.
A conversation with a man from Japan suggested I purchase an item I wanted from Amazon and he provided a link to the item which took me to the Japanese version of Amazon. I had to translate the page to English to read it but I realized the boxes they put us in is growing tighter.
A common item in Japan was almost impossible to find on my American version of Amazon.
I don't use a VPN but it sounds like a good tool for shopping outside of your countries cookies restrictions. Even my go to Chinese shopping sites such as Banggood and AliExpress have further pigeon holed me to regional parts of the USA. They all want to maximize how much money they can squeeze out of someone.
I think I bought my last tv smart box from Banggood for $40 dollars American.
CPU seems cooler than it should be (which makes sense given the very low current draw). I would expect it to be far warmer than everything else on the board, and boot current somewhere around 0.8-1.2A. It is suspicious that the RAM doesn't seem to be powered at all, but if the CPU is not beginning the boot sequence, RAM will not be initialized anyway (but one would imagine it should still draw current even in a standby state). Even without the flash functional, though, it should still draw the correct current and try to boot, and I would think the LED should still do SOMETHING. I would see if you can't find the datasheet for the CPU and figure out if there is an enable pin for the core(s) that's used for power state control.
The CPU boots for the AO power domain, which is very low power. Very few things work in this mode. The IR receiver decoding is one of them. The LED should be on in this mode too. You can boot the box in U-boot mode by pressing and holding the Fn button and then check if there's serial communication. It is basically just a linux/android box.
These boxes usually draw about 600-700mA when working. At least the models with the 5V PSU like this one. As you would expect, the models with 12V PSU draw about 350mA
@@LearnElectronicsRepair Gotcha, either way, lack of boot and low current draw leads me to believe (I think you mentioned it in the video) some low power state (standby or "off") and the device being stuck in that state. Like you said, without proper documentation, not that much else you can do with it. You could try finding that pin on the CPU and applying varying voltages to see if you can't get it to boot, but that's really all I can think of.
It’s tough when you don’t have the OS for that CPU chip, nor a bootable microSD.
Could be worth checking the button. Not that I know how this operates normally.
Please the wife? Fail. hope you have a comfortable couch.😀
as a last resort i flex the pcb while watching the current.
El morte.
lol. Not even going to try and answer that last question. 8|
You can't save them all and sometimes dead means dead. Also trying to please the wife? You really are a glutton for punishment. Keep up the good work.
Так как мы получили кирпич и хуже уже не будет, то...
Прошивка тв приставок на базе процессора AMlogic - или, когда все плохо!
Для начала нам надо понимать следующие вещи
модель
версия платы тв приставки
модель wifi чипа тв приставки
Так же надо иметь
кабель типа USB A to USB A (тут) мы показывали, как такой кабель сделать)
установленный прошивальщик USB Burning Tool
установленные драйвера
сам образ прошивки для ПК
Тв приставки на процессорах AMlogic прошиваются двумя способами: через карту памяти, через компьютер.
It is reassuring that even the professionals can't fix everything.
This looks like corrupted firmware in the EMMC (which is used both as SPI eeprom and storage). The JTAG (if you were able to find its pins) it should give an output only if the bootloader was not corrupted which probably isn't the case here. To reflash it isn't an easy job if you don't have the factory images and an appropriate programmer. These boxes are very basic (nor SD card reader, no USB) even compared to the reference designs. I can't understand why there is so much hype about them and why they are being sold at such high prices. A raspberry Pi can do the same and is more reliable and for sure a lot cheaper.
I know the intent is learning - you do a good job of teaching style videos, but this generic €10 S905 box, I'd probably not have opened.
E-waste from the factory, living on borrowed time from day 1.
Problem with this generic €10 box is that a lot of places here use a service that only works on mag boxes and they are made by infomir who are based in Odessa Ukraine. This has caused quite some problem with supplies as you may imagine. For example the main Spanish distributor had none for several months now and when he does have some the stock is limited and disappears fast. New ones on ebay are fetching silly money. Even used MAG5xx on ebay are about £100 in the UK. But if you know where I can buy 10 or 20 new ones at a sensible price please let me know ASAP. Even used ones cheap would be good. I am looking for certain models, MAG32x MAG520, MAG420. Others are no good, though MAG254 works at a push. These are not Android boxes if that's what you were thinking, they run Linux (AFAIK) and before the trouble in Ukraine trade price was around €65 each inc shipping when bought in 10 off.
@@LearnElectronicsRepair Interesting, I guess the special sauce is in the OS in that case, as the hardware spec is similar to many of the AliExpress Android boxes.
I haven't looked at embedded stuff for a few years.
Loading the Infomir MAG OS onto a suitable alternative 905X2 hardware platform would likely be the ultimate solution to supply issues.
Looks like the Infomir bit is essentially a DRM / Conditional access API on top of Linux.
Investigating how it works and whether it can be transferred to a different platform would be a bit of an undertaking.
eeprom ic