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Post by rbstereo on Jan 17, 2024 23:10:40 GMT -5
I have a recently purchased but working AVR5800 that I loved until it failed a fun afternoon jamming a little loud.
All speakers claim to be 8 ohm impedance.
It got pretty warm I'll admit.
No shorted speakers, backup receivers (even 2 dont come close to the 5800) work fine.
Its a age and heat related failure I am fairly certain.
NOTE TO READERS: THIS SYSTEM MAY NOT HAVE BLEED RESISTORS SO CIRCUITS WITH MASSIVE CAPS COUULD KILL YOU!
I have tried external and internal resets. It keeps going protect. I have not removed any boards. I have not bled down caps. I have experimented with dip sw and main and sub resets. Have not pushed dsp resets for fear oflosing something. I am guessing not the issue.
(Comment here: This is one fine piece of engineering! SERVICER FRIENDLY)
I am qualified tech but respect it too much to risk unguided probing. No manual yet.
I wonder if brief protect over-ride defeat unwise?
Advice requested. $400 invested assuming it might go south given age. But a few months spoiled me. Please help?
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Post by mastertech on Jan 18, 2024 12:36:53 GMT -5
Have you at least check the output transistors for short?
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Post by rbstereo on Jan 23, 2024 18:17:29 GMT -5
I have not yet done so as waiting on a few power resistors to bleed down these MASSIVE caps. Thats my next step once safe levels on the bus. The fact that bus is remaining high makes me think at least half the output stages are good as otherwise i'd see 0 and smell smoke, most likely.
I assume i should have vcc plus and vcc minus, yes? Analog ground at 0vdc?
I smell no burned components at this time so maybe protect helped save some parts.
I'll recheck to see if it bled down over the last few days and use a high value to slow discharge for now.
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Post by rbstereo on Jan 23, 2024 18:18:19 GMT -5
Anyone have schematic link?
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Post by mastertech on Jan 24, 2024 20:30:49 GMT -5
Do you still need a link for the manual?
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Post by mastertech on Jan 24, 2024 22:01:22 GMT -5
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Post by rbstereo on Jan 25, 2024 13:08:51 GMT -5
I'll try creating the account and looking. The only suspicious readings are on the 2 sa1493 but i believe since they match i am not convinced they are bad. The lack of bleed resistors means that even a week on the main caps had pretty high voltagevremaining. This thing would make a decent defibrillator! CAUTION
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Post by rbstereo on Jan 25, 2024 13:09:55 GMT -5
They are not open to new members :-(
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Post by rbstereo on Jan 25, 2024 13:23:26 GMT -5
Turns out i had login but schematics are not valid files best i can tell. Not pdf at least.
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Post by mastertech on Jan 25, 2024 15:29:18 GMT -5
Not sure why you are having problems with the downloads because I downloaded both the schematics and service manual a few weeks ago with no problem. And they were both PDF's.
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Post by rbstereo on Jan 25, 2024 16:35:05 GMT -5
I tried again. Any chance of emailing to me or posting elsewhere? Manual was fine. Schematic failed. I think there are possibly tik tok or other app stuff linked? My cybersecurity settings and risk avoidance nature suggests not to trust this link.
I relaxed firefox settings and tried chrome too. Asking me to install tik tok app is too big a red flag.
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Post by mastertech on Jan 25, 2024 17:49:25 GMT -5
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Post by rbstereo on Jan 26, 2024 9:57:46 GMT -5
I can view now but despite the viewers can download selection it only downloads 1.6kb and it isnt a valid file. I see 25mb in details.
I don't like to use google drive ongoing. Thanks so much but if you have ideas on how to permit full download i'd appreciate it.
I try to stay logged out of google services in a nod to privacy self protection.
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Post by rbstereo on Jan 26, 2024 10:02:30 GMT -5
Current status. Disassembled to determine protect mode cause. Found nothing after cap discharge.
Reset stopped and it now functions with major distortion in preamp as headphones even garbled.
Set idle currents to no benefit.
Going to trace with signal generator and scope to evolve knowledge. Guessing a cap failure on PS. There was only tuner in when failed but all inputs are now garbled.
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Post by rbstereo on Jan 26, 2024 15:56:34 GMT -5
Update. Analog inputs are somewhat muted and distorted. Direct external inputs seem to be fine (full volume and not or less? distorted).
The schematics should help but i believe this may relate to the analog stereo in to dsp feeds.
I have a suspicion on the tuner module. I sense a slight toasted smell (could be dust?) And i think the analog input connectors or the row below may be getting warmer than expected? Thermal camera seems to be showing about 38 degC. Still wondering about a leaky cap or bed diode.
Impossible for me to test hot so far due to harness layouts and a lack of test harness extenders.
If tuner, could this be a marginally aged out component set exacerbated by my somewhat low impedance speakers at higher volumes overheating it?
I'm going to see if i can drop the tuner off the input set to assess if it helps.
For now i can use another units pre out to drive the great output stages of the 5800 into solid 8 ohm or higher loads. Rather volume and heat limit than fry more.
P.S. i found a rear face dropped 5800 used and broken for $50 out of town. When i get it i'm hoping for good spare parts. It looks like speaker terminal bords took the brunt. Hopefully amp boards not cracked. 1000 mi away with my son so it may be a minute til i can lay hands on it. 62 lbs dropped may be components only IF not fried in post drop tests afterwards. One can only hope.
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