Im trying to fix this amp and I'm wondering if the big soup can size caps are kaput (15000uf, 90v.) Ive measured them with a capacitor meter and they seem to be OK,but I haven't measured with an ESR meter? The symptoms are that the rails are supposed to be 78vDC positive and 78vDC negative but it goes from 9vDC to 78vDC and measures 2v 6v 22v on AC as well? Its all over the place,what do you think?
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HP P6-2203a desktop,AMD CPU A8-5500 with Radeon HD7560D,3.20Ghz. Radeon HD 6670.8Gb Ram.2TB HDD. WIN 10 64 bit O/S. -
Re: Peavey CS80 caps?
If the main filter caps are bad, you'll get steady hum and low voltage, it won't wander that much. I'm suspicious that it goes from 78V to 2V without some some smoke. Check the thermal switches on the xfmr primary, if the amp overheats it goes into a low-power mode.
If I remember right, you can unplug power to each channel to see if one channel is loading down the rails.
I found the schematic here: Peavy Amplifier schematics
Had no luck fixing one of these, they are a bear to work on and have only one fuse. -
Re: Peavey CS80 caps?
Oops, this amp doesn't have a soft-start, so I'm wrong about the overheat- it just shuts off primary power. Check the bridge rectifier too.Comment
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Re: Peavey CS80 caps?
Mate Ive checked everything.Ive put in a new bridge,triacs,transistors and replaced all op-amps.it has steady voltage for a while then goes stupid again out of the blue? I just had another go,Ive got 247voltsAC on the primary and 20vAC on the secondary? Looks like the transformer?Last edited by redrooster; 03-11-2013, 02:35 PM.HP P6-2203a desktop,AMD CPU A8-5500 with Radeon HD7560D,3.20Ghz. Radeon HD 6670.8Gb Ram.2TB HDD. WIN 10 64 bit O/S.Comment
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Re: Peavey CS80 caps?
The power transformer is 240VAC primary and 120VCT secondary, or 2:1 for Australia I believe.
I would check the primary wiring for poor connections. I think it goes BLK/YEL to BLUE, AC input is on BLUE/YEL and the BLK. If the voltage is wandering, it might be arcing somewhere, in the tranny or it's wires.
These amps are super-heavy 45lbs. and get beat up doing tours of duty on the road, with bands. They usually smell pretty bad, like cigarette smoke and liqueur...Comment
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I know I've been a little scarce lately (like the last 2-3 years), but I'm still here and still doing my thing with fixing PSUs.
For today's considerations, I have a Seasonic B12 BC-550 [A551bcafh] 550 Watt ATX power supply for you (click on links for full size images).
https://www.badcaps.net/filedata/fetch?id=3591771
https://www.badcaps.net/filedata/fetch?id=3591772
It's a modern ATX unit with fixed (non-modular) cables and an 80-plus bronze certificate. Here's the label:
https://www.badcaps.net/filedata/fetch?id=359177... -
Hello,
First, I am a complete noob with high voltage stuff. I'm learning, but I need help by someone looking over my shoulder.
I recently came into posession of a Heathkit IO-4205 5MHz Dual Trace Oscilloscope. The documentation is copyright 1978. I'm told it works.
I opened it up to check the caps before I applied power, and found the following black caps and wanted to know what they were. They are on the power supply board. I was able to read the name and model and came up with, "Nytronics 162J-1, 0.1uF, 20% tolerance, 2000VDC."
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Hello!
I have two projects on my work bench. One is a friends dead JBL Xtreme speaker with a blown voltage regulator and corresponding bulged and shorted cap. That cap has clear markings so I know what replacement I need for it.
The other project however is a whole different deal. It's a Zoom 9000 guitar effect from the 90th that has developed a devil hound howl when there is no input from the guitar. I'm guessing caps problem. So, since I don't really use this effect anymore I thought it would be a perfect project to learn on.
I have studied the board and... -
I'm trying to repair two old VCRs, they both have bad caps. One has leaky ones, the other would barely run until I subbed in some caps from another power supply I had laying around (though they are the wrong values). This vcr works for an hour or two, but then the power supply starts whining and the picture gets lines in it. I didn't replace all the secondary caps, so another voltage might still be problematic, or the values I used are too far off.
I've been on mouser and digikey but the options are a bit overwhelming. I just need some new ones that will work. They don't need to be top quality,... -
Good evening
I recently aquired a rev 1.1 Gigabyte 60XT, and was suprised of the amount of leaking caps for a motherboard of the P3 era. Especially the way the 330µf caps seems like the housing discolored even.
Now, there are some 3300µF 6.3V KZG series around the CPU. Would it be OK to replace them with something like EEUFR1A332 ? (Panasonic FR 3300µF 10V). Or was this board designed around very low ESR caps?
But I was also suprised about the bigger boys, which are 330µF 25V.
Could it be they used 25V caps because they were cheaper / available at that time?...
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