A man's got to know his limitations. The owner of this radio didn't know his.

@TRXLab

5 жыл бұрын

you are 100% right

@mauricelackey5324

3 жыл бұрын

Got to have a good magnifier, good TEMP controlled soldering iron with right size tip as a minimum.

@markkut9419

3 жыл бұрын

So many spoil good radios when can't do nothing enough good. But here is always them who think can do everything.

@VintageTechFan

2 жыл бұрын

I'm an electronics engineer, quite experienced with soldering (not that much of an expert in surface mount) and I got kinda nervous opening up my european IC-7000 (to open it up for the back then newly allowed 60m band) and took a lot of care and was relieved not to have fried anything.

I see America isnt the only country with people who take the golden screwdriver to perfectly good radios... most techs wouldn't even touch a radio that was jacked up this way. Kudos do you Peter Peter you went well Way Beyond the Call of Duty on this one. We all can tell that you know how to accept a big challenge . The best tech on KZread in my book

Thanks a million Peter for all your help and patience with the messed up radio. Great video with learning aspects

I really enjoy the videos when you repair hack jobs and fried board traces. It really demonstrates your skill and gives me something to work towards in my own abilities. Thanks fir putting this together even though the repair wasn't successful.

Peter, you don't give up easily! That radio was terribly abused. Thanks for the video!

Hi Peter. That was an amazing video. I have many years experience and I would not have gone as far as you did. Your videos and so informative that I have watched most all of them. you are one of the best I have ever learned from. I am retired now but i still dabble a little from now and then. thank you for your effort.

@TRXLab

Жыл бұрын

Thank you!

Wow! That repair work on the vias was really amazing!

Great video. I learned some troubleshooting from you and I have been repairing for many years. You are one of the VERY best. Thank you

@TRXLab

3 жыл бұрын

Thanks for your feed back, very much appreciated

I so much admire your skills and equipment to fix things. However, your willingness to share knowledge one step at a time overshadows it all. Thanks

@TRXLab

5 жыл бұрын

Thanks for comment

I used to do electronics repairs some years ago in my spare time and I truly loved the process.... watching your videos brings back great memories and it also reminds me that there never really was enough money in component repair to earn a living wage because of the costs of time. I think it's impossible to "Make A Living" at it unless a person buys equipment that doesn't work, then repairs it and resells it on eBay/Online or to a Pawn shop. Take a car into the garage for repair and it's like $100 an hour plus parts for service work. Even working out of the home to repair electronic equipment, the repair costs would exceed the value of the equipment in just a few hours of repair work and most people wouldn't be willing to pay more to repair something than to purchase something new or buying even Used in Working Condition... I can see you have a lot of quality test equipment there and I know that it didn't come cheap so I can't imagine that you "Repair Electronic Equipment" for a living. This must be a hobby or a side job / second job for you. Keep making great videos, they are quite detailed and very informative and I appreciate watching them....although...a little lengthy...

That was a great effort! Thanks for sharing it with us. Greetings from Arizona. Mike K8MB.

Another FANTASTIC video!! Congratulations Peter from Brazil. 73 from PY5MM- Mauricio

Great video Peter, much patience and great skill. Thanks for sharing your videos. 73s Pasquale IW0HEX

Now we know why you keep your hair so short Peter. It's so you don't grab handfuls of hair and pull it out when working behind people that make such a mess of the radios.

This video was quite useful to see how you try to repair such a mess. The work rebuilding the vias and traces was amazing. And I must be really interested, because I watched to the very end :)

@TRXLab

5 жыл бұрын

Okay thank you >> so that means my video was not to boring lol.

@stargazer7644

5 жыл бұрын

@@TRXLab No, not at all!

I said that like number 67 was mine here in Brazil! Very good work and knowledge, congratulations TRX Bench.

@TRXLab

5 жыл бұрын

Thanks Luiz!

I never seen do that before I have same radio since 2001 and still works to this day works great for me so far never have any problem with great video Peter !

Thanks for that, nicely done. I have this radio so was even more interested than usual to see it repaired. Pitty about the outcome. I hope some sacrificial spares come available!

@TRXLab

5 жыл бұрын

Thanks for watching

I feel that you were very kind to the person who tried to "fix" the radio before--as if they were your in-laws. It's a self-esteem radio, to make you feel good about the quality of your work. The resistor was added for added inductance : )

How can ANYBODY treat a radio that STILL sells for ~$1000 like that! It almost physically hurts me to see it! I know Peter loves a challenge, but surely this one was always well beyond the call of duty!

I really appreciated and enjoyed this video. It brought back horror memories of my Kenwood TH-F6A that went into meltdown because the "ON/OFF" "switch" was not an actual switch but a "soft switch" which would not allow me to turn it off as it went into meltdown. The protective covers on the right side (mike, speaker, etc.) were missing and some jerk nearly hit me causing the contents of a coffee cup to be spilled into the rig via the jacks on the right side. The battery would not come off unless I removed the belt clip, and since I was driving down the interstate I had no screwdriver to do so. I do wish I could get it working again, but I fear that like the one you worked on in this video, it is simply not cost effective. There were a couple of times that I thought I saw a problem that you may have missed. One such item is at 38:24 in the video. In the upper right part of the screen is a bit of debris that it appears that you didn't see since it didn't show you removing it. There was also a bit of debris above the trace of the bottom left resistor between the trace and the ground plane. You may have taken care of both of those, but I didn't see it, so I couldn't know for sure. Keep up the excellent work!

I own two FT-847's and to see this makes me very sad and a bit angry... I had a similar problem on one of mine but it was the power switch itself. If I held down the switch it stayed on. Eventually temporarily did the mod for the switch and then replaced it... Great video and keep up the work !

@TRXLab

5 жыл бұрын

Yeah the power switch is a known issue on this radio...

I bought an FT-847 the first year they came out and I remember there was a recall for the power switch and I really didn't want to have to ship my 847 to Yaesu just to replace a silly power switch. My radio wasn't exhibiting any kind of problem but after talking with Yaesu they sent me the replacement switch, which I happily replaced on my own.

Excellent video, very informative. Just a suggestion, press the fast and lock buttons together at the same time and turn the radio on this will reset the micro, it’s just a suggestion but it might be that at boot up, some of the initialize code is corrupted, leading to an ‘unknown-status’. There is probably enough code available to ‘force-shutdown’ rather than enter a possible ‘burn-out’ status. One final suggestion, this is from my early PC service days, when a ‘486DX2-66’ was a fast processor. My original IBM PC has directional detection on the CPU Cooling-Fan, if the fan was seized, and not running, the system would lock-down rather than overheating, if the Fans on the FT-847 are not running, could that force the fault you are seeing? Great video again, Bye-4-Now - Neil G1OVH - UK-QTHR.

I just got mine back from a shop in Texas. I bought it used as a newly licenced ham from a reputable shop. There was a few months delay before I started using it on HF since I was only on UHF and didn't realize there was an issue. It had terrible receive quality on HF and I didn't realize the volume was very low. They did several mods including the power switch, found the short causing the issue and brought everything into compliance of spec. It works wonderfully now and its much louder..

Great video as always!

Welcome to my world. The world of butchered and hacked up radios. I swear there are days I spend half the day just shaking my head in disbelief. The sad thing with this radio is before someone started butchering the radio it was probably a easy repair. People need to learn their limits. Good attempt on the repair.

@paul-c7541

5 жыл бұрын

Hi Mike I've seen your video's the patience of a saint, it's seems like let's kill a cb then send it to Mike

@TRXLab

5 жыл бұрын

LOL yeah I know OUR world very well Mike and the issue is it take to much time for a no fix. I guess I have to update my no fix policy...

@ethanpoole3443

5 жыл бұрын

TRX Bench FWIW, I feel it is perfectly fair to charge for time invested into a no-fix, but especially in the case of a butchered PCB where you are likely dealing with multiple atypical faults simultaneously as they can take enormous time to troubleshoot and repair.

Excellent video too well done and very imformative, sad to see someone destroy a great radio. No sure why someone would do such a thing. Peter is really one of the best of the best lots of knowledge and patience and very kind and helpful.

@TRXLab

Жыл бұрын

Thank you Mike

The conclusion is send your radio to a professional to make the modification. Great video Peter thanks for posting

@TRXLab

5 жыл бұрын

you are right.Thanks for watching 73

very informative, well done

I worked for years at a major electronics manufacturer. My first day on the job they made me take a class on proper soldering (and unsoldering) techniques. Even though I knew how to solder, I still learned a lot in that class! It's scary to see the mistakes that some people make: dirty tip on the soldering iron, wrong flux, not wetting the tip first, wrong tip shape for the task at hand, using an iron that is too hot, blowing on the liquid solder joint to "cool it down faster", not recognizing a cold solder joint (or not knowing how to prevent it), etc. etc. There's a lot of metallurgy and chemistry involved as well which can adversely affect the properties of the solder joint after it solidifies from the molten state. Just solder it correctly and let it cool at its own rate.

@TRXLab

3 жыл бұрын

so true

Hi Peter. I had a similar problem with a stereo receiver. I would push the on/off button and the relay that provided power to the whole unit would vibrate. At first I thought the problem was the filter caps in the power supply but replacing them did not solve the problem Finally I started reading about how the reset of microprocessors worked and how the capacitors around the reset chip were a problem. I used the shotgun approach and replaced all of the capacitors around the reset chip and that fixed it. This seems to go along with Nikki Copper’s more rigorous analyses. Hope this helps. Also, thank you for the detail you presented about how processors control radio circuits. John C

@TRXLab

5 жыл бұрын

Thanks for feed back John

You have so much patience. Great video. Show the owner a red card in the future! 73’s Lynton

@TRXLab

5 жыл бұрын

Thanks Lynton 73

Nice video Peter. I did have one of these rigs. It worked fine for a while and then did the exact same as this one. I think i saw i was loosing 5v signal down to 2.4 or something. After some troubleshooting just like you did, it lead me to a small smd regulator on the bottom side of the bord. It was near the relay area . I replace it and the rig would work real good for 19 out of 20 power ups. So once in a while it would not power up. I never did git it working any better than that. Hope this helps you or someone else.

@TRXLab

5 жыл бұрын

Thanks Grant, I believe you mean Q1134 witch is the voltage regulator for the processor....The Q1134 is working fine. Thanks for support! 73

O like número 67 foi meu aqui no Brasil !Muito bom o trabalho e conhecimento,parabéns TRX Bench .

@TRXLab

5 жыл бұрын

do not understand what you mean..

very good video from Gary in the UK.

Have you tried doing a factory reset on the radio? when I have done this kind of mod on other types of radio sometimes the CPU gets confused.

I have no knowledge of this radio. But is that an RS232 port on the back of the radio? Hook up a breakout box and see if the UART initializes (built into the processor?). If it does, is there anything on the TD or RD leads? I say this because as a programmer from this era it was very common to squirt out status messages during initialization of the system and to send error codes (in ASCII) if something goes wrong. Just a crazy random thought....

@TRXLab

5 жыл бұрын

Good point George...Thanks for comment

Those damaged pads next to xtal and the wrongly fitted 2k2 resistor are where the padding capacitor (along with another "select on test" SMD capacitor) is fitted which forms part of the main reference oscillator. What a mess! Big 👍👍 up to Peter for keeping his cool !!!!

excellent video with you hints tips thank you

@TRXLab

5 жыл бұрын

Thanks for watching Mark

@TRX Bench: Did you doublecheck if the coding for the processor is really a valid combination? There's still one track ripped off the board that looked like it was bridged but the missing track makes it an open circuit? Maybe it is some combination of contacts that are not allowed? Since having exactly that TRX as well I might have a look at mine to see what that one would be "jumpered" to if it is not mentioned in service manual?

@TRXLab

5 жыл бұрын

Thanks for comment

Oh man.....1hr 20min video from Petr and at 6:00, we already see this is going to be another case of "The man with the Golden Screwdriver." This is going to be good, I already know it!

@paulmichaelson7203

5 жыл бұрын

This was not a golden screwdriver, this was a golden sledgehammer. I have an FT-847 and it still works fine. It's a great radio and it saddens me to see one mangled like that. This is proof that some people shouldn't work on electronics.

@StreuB1

5 жыл бұрын

@@paulmichaelson7203 You aren't kidding. I think there are some people who shouldn't even be allowed to own nice things, let alone electronics more complex than a hairdryer.

@paulmichaelson7203

5 жыл бұрын

@@StreuB1 Yup, I bought my 847 new in 1997, I've put filters in it, done other mods like the MARS mod, never replaced the power switch and the rig still works like new. It is one of only a couple of rigs that will do cross band full duplex and makes SAT operation easy and fun. I love that little rig and I'll never sell it. It's a shame to see one go so needlessly. I bet 90+ percent of 847s are still operating. Nothing can live forever especially in the wrong hands. 73 de k8idx. 73 to you too Peter, I love your videos.

I've been looking for any FT 847 boards...but 800 to 1200 USD for a 20+ year old radio...got to love the US ham market . :)

This is a painful video to watch on so many levels. No other comment necessary.

@TRXLab

5 жыл бұрын

yeah you are right

Wohl mit dem Brotmesser auf der Herdplatte gelötet, so ein Murkser. Gut dass du die Sauerei wieder hinbekommen hast.

@TRXLab

3 жыл бұрын

HaHa ja so sieht es aus...

Great job, that radio was a mess.

hf transceiver repair is a lot fun, you must have a ball doing it.

Great video!!! I have the same radio that I bought in 1999 for $1500, I've never used it, it's brand new, still packed in the box! Is there anything I should do with the new one that's been packed away for 20 years before I start it for the first time? Thank you in advance! Currently living in 🇬🇧 KE6MFK Merry Christmas 🎄

Made it to the end. Nice video

Nice video Peter!

I have been using this radio for a very long time. for comfortable work on the VHF bands, I installed TCXO

@diabolo3506

3 жыл бұрын

Me too I installed a TCXO on an FT847 while keeping the original assembly that I isolated by cutting a track and moving the 2k2 power resistor, as well as replacing a chemical condenser with a tantalum capacitor to be able to install the TCXO on feet welded to the board. On the rear face of the TCXO with English engraving I installed a power supply circuit with capacitor, regulator, choke, input and output to have a clean and stable power supply. I also installed a micro relay controlled by the ignition off / on switch to prevent the off / on switch from burning by overload. Very clean and invisible assembly for those who do not know the turntable.

I am more amazed how people do something really bad, then try to undo and destroy more, and than just downplay their works. "I cannot understand why it doesn't work anymore" I hope you made him pay a pretty penny for this

Hey Peter... One of your longer videos but because of the content and the valid step by step analysis, the time flew watching this!! It is so unfortunate that FOR NOW, the radio must be put to one side. As you say, the radio seems to be operational, receiving, audio amp OK, mode switching, it just seems for some reason that the DC is not latching. I have no doubt that the owner is not fully forthcoming with the details attempted or the history of attempted repairs. Why would that through hole resistor be changed in the oscillator stage as well as damage to the long track beside it? I guess that there has been a million angry soldering irons attempting mods in that radio long before you were given it. If you cannot repair it, then not much hope of anyone else curing the issues. 73 as always Peter, Brian

@TRXLab

5 жыл бұрын

Thanks Brian, yes that is what I really suspect we don't have the full truth..under that circumstances it is hard to work on a problem. For some reasons it looks like that some mods has been dismantled before I got the radio.. 73

Good of you to show us even when it is not fixed. I would recommend focusing on the destroyed vias etc. in the mode area 1, 2, 3 and 4 at 7:41. Most of the time, it is the last thing that "changed" that is the culprit. The processor is booting up and even running long enough to switch modes and receive. So the processor is probably fine. It has to be some input to the processor, analog or digital input, if it is the processor shutting it down. I am sure you checked that any DC to DC power supplies are not causing the shutdown. Are there any protection circuits/blocks? Did they mess with the bias settings?

@TRXLab

5 жыл бұрын

Thanks James, yeah destroyed vias are a problem but can't find any additionally..DC/DC has been checked out and are found good...

maybe the battery backup switch either needs to be in the on or off position?

Did you check the on/off switch as there was a mode out to put a relay in line so that the switch was only turning on a relay that supplied the power instead of going through the switch.

If you have access to an infra red camera you may be able to see the offending component at power on. Jeff.

Perhaps the power supply is providing the correct voltage but it can't for some reason provide current and as the current tries to surge the processor shuts down? Or some other short pulling the power supply down?

I know it's a 5 years old case, but anyway... I got similar fault in very fast, 2x9pin needle printer with huge power supply unit. The PS unit was switching off after about two seconds from Power On. All voltages were OK (I had to measure them with oscilloscope), no symptoms of shortage in the mainboard, motor drivers etc. The PS was receiving an "emergency power shutdown" signal from CPU. The problem was caused by one of the resistors in voltage divider measuring one of the PS output lines. It changed the value from 20k to 40k, so the measured voltage seen by CPU was 3V instead of 1.5V. So it looked like an overvoltage and CPU immediately halted the PSU. It took me 3 days to find this resistor as at first glance 3V looked quite a good value for a 5V Z80 based CPU, until I made proper calculation ;).

Hi Peter at 7:37 it looks to me like there are two vias on the traces from the processor to solderbrigde 1 and 3. It doesn't look like these vias are conected to the traces anymore. And yes you are right, this mess is something anyone can do without special skills :-)

Hi, it look's bad, I look at your video , where some broken traces from the CPU to solder settings , are there not somme missing vias for pullup at nr. 2 and 3 ?

Great video as always! Thumbs up! I had a peek at the schematics and had one far-fetched thought: What if the undefined state of the broken backup battey switch (S1001) confuses the CPU? Since that switch looked molten to death by a soldering iron and it is close to where the "mod" was done, I thought it might be a possibility even if it might not be a likely explanation. The backup battery switch leads straight to one pin on the CPU. In off state that pin is grounded via 10k and in on state it has 3V from the Lithium cell.

@TRXLab

5 жыл бұрын

Yes you are right. For testing I had the switch hard wired for exactly this purposes. Good thought thanks....

@stevejones8665

5 жыл бұрын

@@TRXLab The Backup Memory Switch is nothing to do with this problem the Radio will work without the Switch or indeed any Backup Battery, all that happens is it will not hold a y memories when powered off If you keep power connected then the Memories and the Radio will still work all ok...I have a Yaesu FT920 with very similar design with the Backup Switch and Battery...Best of Luck fixing it....Looks like a Butcher has tried to do Soldering with a large Hot Poker from the Coal Fire hi hi....Such a Shame.

Hi! Nice video and explanations how different parts of the radio communicate to each other. And yes, this video should be a warning what can happen to all those who will take the old 100W big soldering iron that they used with great success in the 1960's. I have seen stuff like this. And if you still have the radio around, I would give you a hint to try. I have an FT-847 and I did a MARS mod to it, or tried to do. It was bought from German Ebay back around the 2010, so I think it came with your area software and settings. I followed the info on the internet and it didn't work, if I remember right I was on a same kind of situation where it just rebooted itself like that radio. I returned those "jumpers" to original and it worked again. I think there might be different versions of the processor or memory that will not work with MARS-modification settings or with info of the original settings you find from internet. But if you are really sure what pads were connected at factory this might be not the case. But still an easy one to try. By the way, excellent job with repairing those missing traces! I have a working FT-847 here so if you want some info to compare, you can message me.

I would try using an logic analyzer configured to trigger when the reset goes low. I would also set the LA so that there is a healthy pre-buffer before trigger, so you can connect many inputs of the LA to various test points on and around the processor, and then be able to go back and see what happened right before the processor reset. I would also make sure to monitor any interrupt type of pins in relation to the reset line. Could be an additional fault that is generating an interrupt signal that the firmware is decoding to be a power off condition. Last resort would be the "shotgun" approach and simply test all pins in relation to reset, again seeing if anything is happening right before the reset goes low. My last ditch effort would be to freeze the board real good and see if you have any caps or other components that have failed short. Ceramic caps of that era are known to fail short, so you might see that if any device instantly heats up. Should all that fail, I would suggest the owner buy a donor board like you suggested (that and revoke his soldering iron license till he takes a certified soldering class!). (edited to remove suggestion of tying the battery switch one way or the other, as i failed to notice your comment on the subject)

@TRXLab

5 жыл бұрын

Thanks for comment

@trcostan

2 жыл бұрын

I assume he doesn’t do this work for free! At some point it just doesn’t make sense for him to keep billing hours!

I'm only at the point where you found the 2.2K resistor. I bought a broken radio for $300 that was dead. I troubleshot the radio only to find the 100ohm resistor was open. I thought that the resistor was too small and had too much current running through it and decided it needed to be larger. I replaced it with a 2.2K resistor and the radio came to life. I then happened to google the problem (after the I fixed it) and found this to be a common problem and Yaesu made an engineering change to replace the resistor with a 2.2K resistor :-) That may be why it was replaced...poorly so unfortunately.

hmm i only caught part of the video as it was 4am when i fell asleep watching it, now im more interested in the problems that was caused by the battery leak before, id even contemplate reworking the processor pads to clean them and freshen the solder.. however before i seen the bad battery replacement i was thinking bad cap or cracked resistor thats heating up.. what part of the system turns the power relay on/off? where does the signal come from? are you able to jump the relay to see if the signal to power the fet or transistor is stable?

@TRXLab

5 жыл бұрын

Yes I have bridged the relay for testing, all regulators stable. On/Off circuit processor works perfect...

@ianharvey868

5 жыл бұрын

@@TRXLab ok, hmm so what signal is being told to "shut down" and can it be "bypassed" i know its not factory setting but it'd get the old gal' up n running again even with another bodge lol, could it be a sense line from the rf circuit, i know some radios do shut down where others just reduce tx power... interesting issue, it really is

I have one of these rigs and have done a few mods but used a soldering iron not a poker! 73's One rig QRX

I’m sure you covered these but the screw terminals even with power connected went dry joint and I had re-flow these. I had an issue where headphones were once plugged into CW socket in a clients radio and it went into TX as power on and over current. Obviously not what’s going on here but the surface mounts caps are normally 45c working from factory..... yes honestly they are as I worked on camcorders in the 1990s and must have changed 10,000 of the caps for 85c and 105c to give the camcorder a better future. Canon E90 especially. I had this problem on my C2 and trying really hard to remember how I fixed it. See my videos as my C2 is alive and working the birds. Let me check my notes but I’m sure I re-flowed something near the power section. 5 years ago or more....

Thanks for trying to revive it.

These guys with the endless modifications to these radios, they can't seem to leave anything alone. It's amazing how much of this you see, and just say to yourself when one is in front of you, "hammy-bones strikes again."

Hello Peter,I can only tell you about an experience I had with a MEOS TV I have it did the same as your radio, I checked the capacitors, and the diodes in the power supply, all was well, board looked clean nothing showed up no smells, so I put freeze spray on section of the board at a time and switched on, eventually I went to one section powered on and immediately one component thawed out, it was one of those smd caps, so I got the part number off the schematic and I swapped it out, bingo the TV fired up, wife was happy I was relieved , so as the board your working on has been messed about with, could this method help you out. 73 Paul M0BSW

@TRXLab

5 жыл бұрын

Thanks Paul very good approach and a valuable step forward! 73

@izzzzzz6

4 жыл бұрын

i just wrote this in a reply to an earlier comment, glad you came up with this one.

A great video Peter, you showed remarkable patience. I put a suggestion about comparing the serial protocol between a working radio and the dead one. I2C or SPI would make that easier. I also wonder is there a message into the processor right before the shutdown? I wonder if that came from the front panel, or something else.

@TRXLab

5 жыл бұрын

There is a shout down pin at the proicessor but the level is constant so the shut down circuit is not the problem. I put a fix external level to the pin just in case but it did not change the result.

@RadioWhisperer

5 жыл бұрын

@@TRXLab Hmmmm, so the processor is not being told to shut down, but the power to the rest of the radio is being turned off. So I'm wondering how power is being blocked from all the subsystems in the radio? What is the actual mechanism that causes power to be removed, and then what caused that mechanism to activate.

@RadioWhisperer

5 жыл бұрын

@@TRXLab Great work repairing those mangled and destroyed traces. That's something I need to practice more.

@TRXLab

5 жыл бұрын

When power is switched off the voltage regulator for the processor is switched off that then activates the on/off circuit to shut the processor down. That all works....

May i suggest to fix that backup switch?

Was this mod done with a blowtorch? Another great vid, 73 de Malc 2E0EZP.

@stevejones8665

5 жыл бұрын

Yes most likely a Plumber by Trade (No disrespect to Plumbers) or a Red Hot Poker.

@51:00 you show rx tx between front panel and main CPU but you don't measure at the cpu... Perhaps the signal from the front panel isn't making it all the way back? Rx trace at main CPU?

All I can say is BRAVO.

does anyone have a demolition set of the ft-847? my radio missing the covers and the buttons

i am watching this at 2am as i cant sleep but i am hooked on your video now i am wide awake totaly enjoy you video de gm0ioa

@TRXLab

3 жыл бұрын

glad that you liked it. Thanks for feed back

Hi I have a yaesu FT 847 with no audio on transmit on any band or any mode and also intermittent weak receive , if the PTT key is pushed sometimes the receive works again. Any help that you can offer would be greatly appreciated. Thanks in advance.

@TRXLab

3 жыл бұрын

I'm sorry to many root causes possible that I can't say on remote.

Is the power supply shutting down? If so, can you force it to stay on?

@TRXLab

5 жыл бұрын

No power supply is fine and no voltage regulator is collapsing...

Great vid Peter, very sad situation. I have had a look at the manual & as you say it shows no connections apart from the MARS mod lands on the processor - but I'm not sure as I've had strange connections on multi layer boards and the broken track has a land isolated - it appears to go nowhere - but why have a land that isn't used? suspicious....might be pull up resistor somewhere on this line. i would check this out as the user said it worked before the mod. good work - now you need some luck John G1VVU

Ich würde als erstes nochmal den Ein/Aus-Schalter überprüfen ob der auch wirklich noch im gedrückten Zustand den Kontakt schließt und nicht nur während des drückens.. Wie du schon sagtest ist der bei dem Gerät anfällig, deswegen wurde die zweite Schalterhälfte ja schon mit Kabeln dazu geschaltet. Als zweites dann den defekten Backup Schalter neben dem Prozessor ersetzen, dadurch das der obere Teil fehlt wird ja jetzt gar kein Kontakt geschlossen, dadurch könnte der Prozessor vielleicht blockiert sein. Und natürlich die Batterie wieder anlöten nicht vergessen.

@TRXLab

5 жыл бұрын

Der Ein Aus Schalter ist nicht das Problem da ich den auf dem CNTL Board gebrückt habe...Der Back Up Schalter ist mit einem Kabel verlötet..

Great !

it's not the processor. keep digging. (reheat the soldering of the processor, with hot air, without removing it from the board. The solder Yaesu used tended to crystallize and make intermittent or no contacts after 20 years of use.)

@TRXLab

5 жыл бұрын

Thanks Pop that is a good hint. I know this issue when the solder melts it feels like chewing gum. I always test the IC pin by pin with a sharp hook and normally you will find a loose connection by this approach. In this case all the pins were in good condition.

Check the POR of the cpu. The power rails. The cpu can be found and be replaced ( in the worst case ) if the program memory is outside of it.

Peter I know it's a long shot but have you tried the Processor reset procedure..I would also suspect the Guy with the Hot Poker has also fried some of the Capacitors, you only have to look at all the plastic that be has melted with his Iron to realise he hasn't got a clue how to do basic electronic soldering.

Late saturday evening, without my tea...unususal...but i could not resist! Just hammering down some car jumper cables with a torch and huge amounts of lead isn´t fixing a problem..may we should produce an sell some stickers with that hint. I wonder, what triggers the unit to shout down, and what to do to bypass that behaviour. Ok, normally it should protect the unit to fail / burn/ lift off, but as you said, it works fine for 2 sec, no exessive current draw or things like that. So maybe it is possible to hard wire and do some rerouting to eleminate this shutting down? Problem is: How much time could you spend to this thing? There are many hours left to check every bus and voltage, every cap etc. Anyway: Fine job again so far, i like it very much. And be sure: You will get the Luis Rossman diploma for SMD and via-bridging repair! Thats for sure! 73 de Olaf

@TRXLab

5 жыл бұрын

LOL yeah Olaf lets produce some stickers.....Ja das ist schon ein sehr interssanter Fehler nur die Zeit die es verschlingt die Zustände am Prozessor alle zu testen it einfach zu lange. Zusätzlich wissen wir leider nicht ob einfach irgendwo eine Durchführung zerstört wurde die wir zur Zeit nicht sehen. Bei all den komischen Vorschädigungen musst du mit Allem rechnen. Leider sind auch die Angaben in den Serviceunterlagen für solche Fehler mehr als mangelhaft und bei Yaesu hat niemand mehr Lust und Zeit sich mit einem Funkgerät zubeschäftigen das komplett aus dem Service raus ist. Auch bekomme ich die internen Fabrikunterlagen nicht. Die würden helfen das Problem weiter zu ergründen. Aber alles das wäre dann nur noch persönliches Interesse was ich aber gerne investieren würde, wenn ich mehr Informationen bekommen könnte. Du siehst solche Fälle ziehen einen Rattenschwanz hinter sich her...Aber wem sag ich das LOL.... Danke fpr Deinen Kommentar 73

Measure the base of Q1122. After hitting the power switch, Q1118 holds it low for a short amount of time, then it should get a hi signal from IC Q1106. Find out why that signal disappears. (and de-energizes relay RL1001) As you said, there are no PSU overloads, so I would even force that signal hi. (cut the trace before)

@TRXLab

5 жыл бұрын

For testing the Q1118 was out. The 1118 is the over voltage protection which pulls the Q1122 to ground in order not to kill the radio..

Somehow disappointing that there was no rescue. But I learned a lot what can be done and a lot more what you should never do.

Moral of the story. Do not open the case if you don't know what you are doing. A good tech is worth the price.

Hi Peter, When the radio shuts down, I hear a relay click, can you trace back from the relay to see what is shutting the relay down. Thanks for all the great videos.

@TRXLab

5 жыл бұрын

Thanks Rich, I have by passed the relay to see if everything works stable...

@MrPerrey

5 жыл бұрын

@@TRXLab - And, Peter, by- passing the relay, whats happen then?

@stargazer7644

5 жыл бұрын

@@MrPerrey Please watch the video. 1:07:31

@MrPerrey

5 жыл бұрын

@@stargazer7644 - Now I saw it. Peter did o many things - I'm convinced that's the uC, sadly...

Acid core solder and a 500 watt iron works every time!

My comment has more than likely already been covered, And this video is fairly old now, But all the time watching this i was thinking "I'm sure the backup battery has to be connected for it to power on" And when you first opened it there was a backup battery someone bodged in, but the backup switch was broken so the battery wasn't actually in circuit, Did you ever try a new battery and replace switch, Or solder the two tabs of the switch together so its on ?

The black band on your wrist, I think you said it protects the radio against ESD, what is that? Forgive me if I got it wrong.

@TRXLab

5 жыл бұрын

That means electric static discharge and that means dependent on the circumstances your body can be loaded with many thousands of volt. If this load hit a uP it is toasted..

@mickyjb2003

5 жыл бұрын

TRX Bench Thanks, I thought it was that,but thought I would ask. Static electricity I have seen when you get a jolt from it you wonder how on earth can that happen.lol

The golden screw driver strikes again soldering with a hot nail

@F_Tim1961

3 жыл бұрын

I think you meant against ... TEF

Mr, there is one great thing I would like to know about you, and is where are you from, and if I can get from you some books on electronics, in especially transceiver radios, how and where can I get antenna buster for a radio that i have its a cobra, 18wxst11 40 channels, please thank you

Yaesu Christ, it's a wonder the person who did the messy damages, found the right screwdriver to open the case.

@TRXLab

3 жыл бұрын

lol yeah hard to believe..

As far as I'm concerned, the owner can do whatever he wants to his own radio. It's no skin off my nose if he bricks it. I am more distressed by people who decide it is helpful to heap criticism on top. That is contrary to the mission of amateur radio in that such criticism can discourage people from experimenting. It is amateur radio, not professional radio and I try to always be welcoming and encouraging to anyone who wants to participate. It is not a place to play "King of the Mountain".

Jeezo! someone has rap*d that lovely radio :(

Wow someone has been in with The magic screwdriver 😆😆

@ethanpoole3443

5 жыл бұрын

More like the magic sledgehammer going on the looks of that board!

@stargazer7644

5 жыл бұрын

And the magic propane torch.