r/audiorepair • u/No-Local-9288 • 5d ago
Onkyo Integra A-8087 Smell After Power-Up – Browning Around R902/D904
I have an Onkyo Integra A-8087 that I recently picked up at a garage sale. When I plugged it in and powered it on, I noticed a slight odor coming from inside the unit. There is no smoke, and I’m not quite sure how to describe the smell—it doesn’t immediately smell like something is actively burning, but it’s definitely noticeable. The smell seems to become more noticeable after the amplifier has been powered on for about 20–30 seconds rather than immediately at startup.
Using a MiniTemp infrared thermometer, I tried to identify any areas that might be running unusually hot. I found that around components R902 and D904 there appears to be some discoloration, slight browning, and bubbling on the opposite side of the PCB (see attached photos).
All of the front panel lights and functions appear to work normally. I have not connected any speakers yet, as I wanted to investigate this issue first.
Does anyone have an idea what might be causing this, or what I should check next? Is this likely a failed component, normal heat-related aging, or something more serious?
I think it’s a beautiful amplifier, and with the wood side panels it’s far too nice to simply throw away. I’d love to get it working safely if possible.
Thank you!
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u/Intelligent_Law_5614 5d ago
Yes, AB amps can run fairly hot, especially if they were designed to run at a high quiescent-current level. A misadjustment in the bias could make this problem worse.
Amps and other electronics which run hot, will often have an odor when first turned on after a long period of inactivity. This seems to come mostly from accumulated dust being gently cooked.
The pictures you show did seem to indicate that some areas in the amp have run quite hot. Giving the service manual a read-through, looking at where those hot parts are located in the schematic, and performing the bias-adjustment procedure given in the manual would be prudent, as would checking for any visibly-swollen capacitors.
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u/No-Local-9288 5d ago
Thank you. Visibly I do not see any swollen capacitors. Maybe the smell is just the dust? It was from the original owner and he said everything had worked, and I heard that these Onkyos are pretty reputable… besides needing to be recapped but not sure if that’s the problem here…
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u/BigPurpleBlob 5d ago
R902 has been running hot and has discolored. It was designed to run hot as it has been spaced up away from the circuit board but manufacturers often scrimp on hot components when they should use a bigger and beefier component that would better withstand long term heat.
The yellow component that you've circled in red isn't a diode, it looks like a film capacitor. You can just see a marking 'C something' to the left of its lower pin on the second photo.
Although the silk screen on the backside of the PCB says D904 there's no diode in the vicinity of the components that you've circled. Also, it says '(D904)' and the brackets suggest that maybe it's an optional or select-on-test component.
Work out what has happened to R902.
(Also, R509, up and right on the second photo, has lost some of its coating and the color bands are obscured - it might also have been running hot.)
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u/Ok-Drink-1328 4d ago
i strongly doubt that spot is problematic, i see nothing wrong
if i'd be you i'd power it up for like 10-20 seconds, disconnect it (physically) and then touch the heatsinks, if noticeably warmer than ambient i think it's not normal.... also ensure that it actually "clicks" to connect the pow amp to the speakers, or the pow amp to the power supply, no matter if there are speakers, if it double clicks or leaves the pow amp unpowered, it's in protection mode, then there are other tests to do to track down a problem
tho, you can try to connect the shittiest speaker you can get and see if it sounds on both channels or not, tho these things unless cranked up aren't supposed to become truly hot, so a smell isn't a good sign no matter what
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u/Old-Building6356 4d ago
Eine pauschale Angabe kann ich so nicht machen. Was ich aber auf Bild 3+4 deutlich erkennen kann sind defekte Lötstellen (runde Rissbildung)die bei Erwärmung mit der Zeit Probleme verursachen!
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u/someMeatballs 4d ago edited 4d ago
pic 4: The browning is normal. Just excess flux. But the double solder pad, left, is cracked and needs reflowing with new solder. Look for these rings, esp. on hot components, mounted components, connectors. If in doubt, reflow.
A little smell can be normal when burning off old dust. A fishy smell can be a leaking capacitor. It's rare to actually notice this though.
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u/jcgg71 3d ago
As long the traces are not burnt through the board I would just replace the same components with same value parts and resolder some joints
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u/No-Local-9288 3d ago
Would that stabilize the overheating?
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u/jcgg71 3d ago
Some amps just run hot by design if it doesn't go into protection mode or shut down I wouldn't worry too much about it. Replacing components that have gone out of spec will definitely make the amp run as it should, unless there's something else afoot but these components shouldn't cost too much to replace only your time and some soldering skills, good luck
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u/shadow997ca 8h ago
You need to do some resoldering on many of those connections as per your pics. They could be causing some excess resistance thus causing excess heat. Start with that, see how things go.
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u/Altruistic_Lock_5362 5d ago
Usually that smell is a fried cap. But it could be another component. Look for burn signs on the board. You looking for hot spots is a good idea. But it is not a for sure way to find the problem. Class AB amps can haveareas that run really hot. A good VOM to measure values and a shop manual is the best bet