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I have a client with several CA6s. All have bad power supplies. Solder looks "cold joint" on all the diodes. Well I've resoldered all diodes and replaced the leaky caps but it still stays in protect. Im wondering if theres a factory bulletin on this amp before I go farther. Anyone know of one? I'm getting no response to my email to crest.
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I don't know of any bulletins, but I have had some experience on the CA-series.
If any of the main filter caps were leaking or if the vents are bulging you should replace them all - these have a history of failing in spectacular fashion with holes in the PCB as accompaniment.
The diodes you mention are probably the Zener diodes in the low voltage supply and they do run very hot - check each one for shorts. The large stand-up resistors (which feed those diodes) often develop bad solders and also a poor connection from the top lead to the steel support, which is used as a conductor to the PCB.
Here's where I'm a little foggy: I THINK you can fire up the amp with both output modules removed or disconnected and the protect relays will click on after a short delay. Is this how you are testing? If so check for the presence of even & opposed rail voltages as well as low voltage rails either at the regulators or a handy IC.
If you are testing with modules connected I would suspect a shorted output transistor (or more likely a bunch) on one or both output modules. You can try with one, then the other disconnected & pulled out to narrow things down.
I've worked on numerous CA-series amps out of nightclubs that would stay in protect due to the presence of fog-juice residue mixed with dirt on the fan end of the output PCB's. I usually take those to the sink with a paintbrush & some Glass Plus and completely wash them down. Compressed air helps speed up the drying process after that, and the hunt for arc-damaged or eroded traces can begin...
Good luck! -
Modules are good. I ran them in another amp. Thx for your reply Mark.Comment
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