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This turd landed on my bench. Yamaha A/V receiver. Blondie's oldest son who dumped water into it. Completely dead. No power. I told him I'd look at but no promises. I have found so far that the standby PSU is OK. But the balance of the PSU's won't come up. Figuring out what's what on these computer controlled receivers is a nightmare. Luckily I did find the service manual for download but it's still a daunting task.
The water fell on the power amp and main supply on that lower board. Luckily it missed the upper logic board or else I would have refused any attempt at a repair. But as I stated above I'm not gonna kill myself trying to get it working. And at the very least I have to pull both boards and clean the power amp area with IPA. Welcome to my nightmare.
An old gray beard with an attitude. I don't bite.....sometimes
I found one put out for recycling a couple of years back, a Pioneer VSX-324. There was no remote control with it. I took it home and opened it up out of curiosity. I found a manual online but as I'm not into TV, I couldn't get excited over it. There were a few useful bits and pieces.
I looked them up on ebay. It seems as if you can get a used one of that sort, or similar, for £40. I couldn't generate much enthusiasm to look into it further.
It's always worth having a look at these things, because a lot of faults with electronics are basic, such as blown fuses, or loose connections, or bad switches. But there's only so much (not very much) it makes sense to do.
And bad crapacitors, which is right up MED's street.
I've just swapped out a Harmon Kardon 5.1 amp for an Onkyo 7.1, which I bought as parts only on ebay for buttons. Turns out it works fine... so I'm playing with a Philips PM2503 on the bench of doom instead
With the aid of the Service Manual the receiver was in "Protect Mode" and gave instructions to bypass it, with appropriate warnings that additional damage might occur. I went for it and amazingly it powered up with no magic smoke. All functions on the display appear to work. The big test obviously are the analog and power amps OK. Quick test with a scope confirmed analog signal on all 7 channels. Connected speakers after checking for DCV on the outputs and the damn thing is working! Perhaps this thing isn't a turd after all. The protect circuitry did it's job and shut it down before any damage could occur. I guess I could agree that Yamaha stuff is pretty decent.
Informed the kid and he's obviously happy. The only thing I want to do is clean up the power amp board as best as possible without ripping it apart.
An old gray beard with an attitude. I don't bite.....sometimes
I like success stories, and now you are not some weird old guy with a lot of obscure junk, you are an undeniable HERO, who has saved a useful number of dollars. You can find there are cascading faults in these things.
I do believe that modern electronics are not really intended to be maintained, despite the fact that the more reputable makers produce service manuals, so kudos to you for fixing it.
Zenith wrote: ↑Sun Apr 14, 2024 6:13 pm
I like success stories, and now you are not some weird old guy with a lot of obscure junk, you are an undeniable HERO, who has saved a useful number of dollars. You can find there are cascading faults in these things.
I do believe that modern electronics are not really intended to be maintained, despite the fact that the more reputable makers produce service manuals, so kudos to you for fixing it.
Oh but I am that weird old guy with lots of obscure junk. TE Closet. And that's only the left side. Right side is just as crowded. And in the downstairs storage area there are multiple totes of circuit boards/parts/etc, multiple stripped 500 and 7000 series plug-in's, and at least 8 battered scope chassis.
And I'm no hero. The electron gods smiled on me, for once.
An old gray beard with an attitude. I don't bite.....sometimes
MED6753 wrote: ↑Sun Apr 14, 2024 9:03 pm
And I'm no hero. The electron gods smiled on me, for once.
I've been a hero on several occasions, once by fixing a trail camera that was about to be thrown away. It had corroded battery contacts. Lap it up while it's on offer, but don't believe it yourself.
MED6753 wrote: ↑Sun Apr 14, 2024 9:03 pm
And I'm no hero. The electron gods smiled on me, for once.
I've been a hero on several occasions, once by fixing a trail camera that was about to be thrown away. It had corroded battery contacts. Lap it up while it's on offer, but don't believe it yourself.
Dexion is pretty good for anything like that, apart from the fact it's expensive. I got mine out of a skip when the local shop was redoing its stock room.
MED6753 wrote: ↑Sun Apr 14, 2024 5:07 pm
With the aid of the Service Manual the receiver was in "Protect Mode" and gave instructions to bypass it, with appropriate warnings that additional damage might occur. I went for it and amazingly it powered up with no magic smoke. All functions on the display appear to work. The big test obviously are the analog and power amps OK. Quick test with a scope confirmed analog signal on all 7 channels. Connected speakers after checking for DCV on the outputs and the damn thing is working! Perhaps this thing isn't a turd after all. The protect circuitry did it's job and shut it down before any damage could occur. I guess I could agree that Yamaha stuff is pretty decent.
Informed the kid and he's obviously happy. The only thing I want to do is clean up the power amp board as best as possible without ripping it apart.
I'm a bit confused. Have you circumvented the "Protected Mode" for the troubleshooting or have you resetted it, so that it will do its job in case of a next (water spilling) incident?
Zenith wrote: ↑Mon Apr 15, 2024 10:27 am
I'd hesitate to use plywood. I've noticed it's very prone to woodworm.
Hearing this for the first time. Any interesting stories you could share with us?
Nothing particularly interesting, but observations I've made over the years. My parents had a wardrobe with plywood feet, which were so riddled with woodworm they fell apart. The rest of the wardrobe was untouched. A board to which an electricity meter was attached, falling apart with woodworm, with nothing else in the house affected. Several other instances of plywood being infested with woodworm, to an extent I've not seen with other woods.
Generally, I've noticed that woodworm have a great liking for plywood, so much so that I think twice before using it.
MED6753 wrote: ↑Sun Apr 14, 2024 5:07 pm
With the aid of the Service Manual the receiver was in "Protect Mode" and gave instructions to bypass it, with appropriate warnings that additional damage might occur. I went for it and amazingly it powered up with no magic smoke. All functions on the display appear to work. The big test obviously are the analog and power amps OK. Quick test with a scope confirmed analog signal on all 7 channels. Connected speakers after checking for DCV on the outputs and the damn thing is working! Perhaps this thing isn't a turd after all. The protect circuitry did it's job and shut it down before any damage could occur. I guess I could agree that Yamaha stuff is pretty decent.
Informed the kid and he's obviously happy. The only thing I want to do is clean up the power amp board as best as possible without ripping it apart.
I'm a bit confused. Have you circumvented the "Protected Mode" for the troubleshooting or have you resetted it, so that it will do its job in case of a next (water spilling) incident?
It was circumvented for troubleshooting and after I determined that it powered up OK I reset it. It continued to function normally. It was a lucky day for both of us.
An old gray beard with an attitude. I don't bite.....sometimes
He's probably older than you. 
TE Closet. And that's only the left side. Right side is just as crowded. And in the downstairs storage area there are multiple totes of circuit boards/parts/etc, multiple stripped 500 and 7000 series plug-in's, and at least 8 battered scope chassis.
