CA-810 Output problems

Rentz

Active Member
I've been using a Ca-810 i got in barter town for about the past 1.5yrs without much problem but i noticed the occasionally hum in the speakers which came on powerup and went away.
Flashforward and now the hum is there all the time
new symptom is now my tape loop outs i used to archive and for a headphone amp are terribly noisy to the point i cannot use them.

to my knowledge its never been re-capped, i have given it a cleaning out on the inside and used deoxit on the output jacks and the knobs.

Any suggestions on problem spots to check? I'm not well versed in electronics but my father in law is, as long as its a basic fix.
 
Hums are problematic to solve with many causes. Would be helpful to know if it's mains 50/60Hz or rectified 100/120Hz hum.
Apparently, there's a mobile phone app that can measure. The sucker bet is to replace the main filter caps, yes, they may be
the problem but there are many other causes...
 
A complete power supply recap would probably go a long ways.
 
Thanks, I’ll see if that’s something I can tackle or maybe just find someone local to overhaul it .
 
I've been using a Ca-810 i got in barter town for about the past 1.5yrs without much problem but i noticed the occasionally hum in the speakers which came on powerup and went away.
Flashforward and now the hum is there all the time
new symptom is now my tape loop outs i used to archive and for a headphone amp are terribly noisy to the point i cannot use them.

to my knowledge its never been re-capped, i have given it a cleaning out on the inside and used deoxit on the output jacks and the knobs.

Any suggestions on problem spots to check? I'm not well versed in electronics but my father in law is, as long as its a basic fix.
Need to check a couple things first.Very basic stuff.
 
Unplug the two jumpers on the rear panel. Turn on unit and see if it still hums or if the hum changes characteristics. The removed jumpers will separate the pre-amp from the power amps. And hopefully, eliminate one or the other.
 
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Unplug the two jumpers on the rear panel. Turn on unit and see if it still hums or if the hum changes characteristics. The removed jumpers will separate the pre-amp from the power amps.
Don’t even have to try that, it removes the hum so does turning off the preamp or lowering it via the switch
 
C801,802,C805,C806,C807,C808 and C813 These may even show signs of stress.
 
Hifiengine has a crappy scan of the service manual. A most excellent HiQ complete copy can be obtained here.
I highly endorse Normans manuals.
https://www.analogalley.com/osccart/product_info.php?manufacturers_id=55&products_id=2267

It will definitely help with disassembly And locating those capacitors I mentioned earlier. Go with the same µf and voltage as what's currently installed in those locations. Personally, I would go with Nichicon UKL's.
 
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Hifiengine has a crappy scan of the service manual. A most excellent HiQ complete copy can be obtained here.
I highly endorse Normans manuals.
https://www.analogalley.com/osccart/product_info.php?manufacturers_id=55&products_id=2267

It will definitely help with disassembly And locating those capacitors I mentioned earlier. Go with the same µf and voltage as what's currently installed in those locations. Personally, I would go with Nichicon UKL's.

Thanks ! I had the ones from hifienfine and it’s a bit hard on the eyes this one will help
 
Some of those caps may have dried glue around them. I would remove any dried glue that I would find within the unit. It usually chips off easily with an exacto chisel blade.If any of that glue came in contact with component leads or jumper wires. Inspect for corrosion/oxidation.
 
I had some odd hums from my CA-810. Ended up being from interconnect cables. Straightened them out and no more hum.
 
All ground wires between boards and grounding screws that attach the boards to the chassis?
 
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