tony359
Badcaps Veteran
Last Activity: 07-14-2026, 07:03 AM
Joined: 10-28-2018
Location: Swindon
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You're not being cynical, you're being realistic. It's so sad.... -
cheers! Thank you all for the help!Leave a comment:
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Part 2 is here - thanks again Agent24 for the help, I mentioned you and this forum in the video! The link to this discussion is in the video description
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In normal circumstances I'd imagine that board is running at 60C all the time. I suspect those caps were of the worst quality - the ones on the input of 12V were the only Nichicon I could recognise, CW series, and guess what? they were fine.
Particularly with SMD, I feel companies see that as an easy "timebomb" into their products. People cannot easily determine the quality of the component and they WILL die after many years, far after warranty has expired yet within a decade or so, forcing the user to buy a new one.
On next video I'll show more overheating going...Leave a comment:
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made my usual repair video on this unit, this is part 1, the buzzing noise is explored in part 2, where I also mention this thread ๐
I...Leave a comment:
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Agent24
Bingo.
+15VA was heavily rippled, the cap on the +22 line was dead. Because... Onkyo in their infinite wisdom installed the bridge rectifier UNDER it **AND** it is an 85C cap. What would possibly go wrong. -15V is ok but I am swapping the -22V cap as well to be safe.
I don't have a replacement (schematics say 35V, I found a 50V installed, I'll go with 50 to be on the safe side) but it's clearly the issue.
Thanks so far!...Last edited by tony359; 01-31-2026, 02:17 PM.Leave a comment:
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I kind of suspected that, though is that a thing for 50hz as well? I thought it might just be an issue with higher frequencies.Leave a comment:
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I checked the ripple on +12VHDMI, I believe it was 500mV which I feel it's a bit too much but that +12VHDMI goes through multiple regulations and the resulting voltages are all good. I checked C4007 in circuit from the +12VHDMI and it was indeed reading good values. But I will look into that again, including the other voltages coming from D4009.
Thanks, I'll take a look. In any case, I guess I want to check all the main rails (the two +12V) and if those show ripple, I can look into why that happens.
One question: would a SINGLE 10000uF capacitor be able to provide...Leave a comment:
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stj
yes it's 100hz.
Agent24
I will test them better but in circuit they did test ok. The thing is that the 12VHDMI is then further regulated once or even twice so I doubt that is my issue.
I had a look at the schematics, I will begin from the transformer, follow the various rail generation, check them with the scope and check the caps with my ESR meter. I will also check the standby voltage, you never know it's just sitting there in the background injecting noise into everything
Thanks so far!...Leave a comment:
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Update. I eventually re-capped the "HDMI" board entirely, every single cap I tested on it was bad.
Unfortunately the noise is still there, unchanged. So let's assume it's not the HDMI board and it's not the amplifier board as it's quiet if I unplug the inputs.
I will have a look at schematics but how do I trace a buzzing noise with a scope when it's so low I can barely see it on the signals - but it's pretty obvious on speakers? I'd imagine mains buzzing noise is mostly coming from badly filtered rails, right? I mean, there is no other way, right? So I'd imagine...Leave a comment:
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I heard the MG is good indeed - and also inexpensive last time I checked.
I ended up "settling" on a Warton flux made in the UK - I need some consistency with the flux which my favourite aliexpress seller could not provide. I feel it's ok, it's not cheap but cheaper than Stirri. I'll keep exploringLeave a comment:
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Apologies, it wasn't a video, it was an EEVBlog post.
Here is various NoClean flux left on a copper PCB. MG Chemicals is number 2. I see your point, Tony, but I don't see why I should use flux which is corrosive under some circumstances. There are non-corrosive alternatives available so to me the MG Chemicals is a no-go.
Link to test: https://www.eevblog.com/forum/chat/g...ering-flux/75/
Test on copper MG Chemical 8341 is number 2
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Cardinal Fang
yes, that was the issue. There's a video online where someone spread various fluxes on a copper board. The MG one left a green patch behind so it's definitely NOT a "no clean" which is disappointing as I thought MG Chemicals was a proper company.
stj
The test was done with cold flux left on a copper surface for a number of hours/days. I always clean my "no clean" flux but I cannot reach under chips and I cannot ultrasonic everything every time so I'd like to avoid what is CLEARLY corrosive. Then, of course, I'll do my best to clean any...Leave a comment:
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Cardinal Fang
I saw great comments about the MG Chemical one but then found reviews confirming it's corrosive when left on copper. Might be mildly, might not be a big deal but I don't want corrosive stuff on my PCBs. Too bad because it's cheap....Leave a comment:
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the 806 is also probably from the capacitor plague time - or shortly afterwards. The board is also the hottest of the lot, at the top of the unit - obviously no fans (unless the amp is about to go on fire), no heatsinks so those caps have a tough life.
Given that the only "branded" caps I could identify look perfectly fine, I'd be more inclined to think that Onkyo cheaped out on some caps. Maybe... intentionally? who knows...
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Iโm not sure, I donโt recognise most of them, theyโre SMD.
the only ones I recognise because they have the Nichicon logo on them, are good - surprise surprise ๐...Leave a comment:
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That's a good idea, thanks.
Meanwhile I determined that all the other 100uf/4V caps have ALL died and when I went to check a 220uF and a 100uF/16V, they also died so the board needs a full re-cap regardless....Leave a comment:
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Onkyo SR806 buzzing noise on outputs
HI all,
I'm trying to repair an Onkyo SR806. Originally it had the usual "faulty DSP" sympthoms but it turned out that the supply voltage of the DSP chips was oscillating. I found both capacitors after the linear regulators for the DSP supply to be dead and that was causing the issue.
Once that was resolved, I focussed on the other issue: a pretty loud buzzing noise from the speakers, the usual 100Hz (I am in the UK so we have 50Hz here).
I've unplugged the amplifier board from the inputs and there is NO noise so the issue is in the signal being... -
Surface Pro 7 1866 - Windows logo for 4 seconds then turns off
Hi all
I've decided to purchase this Surface Pro 6 hoping for a simple fix but it isn't ๐
When plugging USB-C I have 20V and about 6W which then go down to 4W over time. When ON button is pressed power goes to 9W then it stops and goes back to charging wattage..
I tried all the possible combinations (enter BIOS, reset etc) with no luck. I see even the PD resets when holding power for 30s but it then goes back to what I described.
I'd imagine I'll have to detach the screen and diagnose, right? Someone suggested to drain the battery with those 4... -
We like Pizza! ๐...Leave a comment:
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