Yamaha CA1000 III

Azza

New Member
Hi!
Im a new member on this forum and this is my first post .
Before I get onto my question, just a little introduction. Im primarily a musician and music maker who has recently discovered a love of all things electrical and old. It started with synths and audio efx and has now moved onto amps and speakers . Living in Japan gives me access to alot of the early stuff made by various Japanese companies. I have up until now been repairing old junked synths and audio efx and this is my first amp to try and fix.
I recently purchased a Yamaha ca 1000III for quite cheap as it was not working and Im now trying to diagnose the source of the problem. I plugged it in and connected my old ns10 speakers just in case something bad happened.
heres the details>>>
It powers on and the meter show an REC out/mv signal but no speaker out/W.
The volume is very low and distorted and only comes through on one of the phono inputs.I took off the cover and the inside is quite dusty .
I did some trawling on the web and found some other people referring to a similar problem with the same series of yamaha amps (but no solution) which makes me think its a common fault.
If someone could point me in the right direction as far as what possible component could be faulty it would be much appreciated. I do plan to take it apart and give it a good clean while Im repairing it and replace any bad caps with my trusty ESR cap tester (though I dont think caps are the problem).
Thanks in advance ,
Aaron
 
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I'd suggest you do some reading on amplifier theory. Not to discourage you, but repairing these amps is very rarely as simple as "oh, just replace capacitor C301 on the power amp board". By the sounds of it, the pre-amp section is working. You could determine this for sure by running the pre-out of the CA1000 into a working amp.

Does the speaker protection relay click a few seconds after you turn on the amp? Given the distorted sound, I'd be inclined to pull the outputs and test them for starters.
 
Hi !
Thankyou for your quick reply. Yes ! I think you are right , I will go and do some research about amplifier theory and come back to the idea of fixing it after I have an idea of whats going on!
Yes speaker protection relay clicks after its switched on. Thanks for the starting point ... I'll start there after Ive done some reading.
 
Clean the switches and controls real well with Deox-it if available. Don't forget the coupler switch on the rear of the unit they are notorious for being really dirty or even in need of replacement (switches are available with minor modification).With the unit powered up at a low volume level work all the switches and controls up,down and from side to side.Especially the rear coupler switch..Listen for the amplifier cutting in and out.:yes:
 
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