Yamaha ca-800 II right channel died

FreekT

FreekT

New Member
I recently bought a yamaha ca800 II, back then I thought it sounded great and worked fine. :thmbsp:
Just now I tried at home and it seems the right channel has no output :thumbsdn:
Any idea's?
Was thinking of making it my project and try fixing it myself :scratch2:

Thanks in advance for all the great support
 
Does it play both channels when switched to mono ? Did you try both speaker A and B ? Did you swap your input cables around ie. left to right and right to left ?
Might just get lucky and just have a dirty switch or control.
 
Flip the coupler switch on the rear panel back and forth a few times and listen for the missing channel to cut in and out. That switch is notorius for being dirty.

BTW welcome to AK...:thmbsp:
 
I opened it and noticed 2 blown fuses of the 8 in there, will be replacing all of them and give it a shot.
Hopefully it was just the age of the fuses that killed them
 
Hmm,
I again the fuses blown and now my left channel isn't working either...

Will open him up again and think I'll just start replacing every electrical component I encounter :sigh:
Anyone knows if these are hard to recap everything?
 
FreekT said:
Hmm,
I again the fuses blown and now my left channel isn't working either...

Will open him up again and think I'll just start replacing every electrical component I encounter :sigh:
Anyone knows if these are hard to recap everything?
Click to expand...
Just throwing parts into it is the expensive route to go. I'd repair the malfunction first before even thinking about a recap.

Check your output transistors in the right channel. You do know how to check transistors with a multimeter don't you ?:D
 
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I asked a local hifi repair guy what the costs would be for the repair, but 250 euro seems a bit expensive.
I really have no experience at this part at all :no:, but I hope with some patience and research I will be able to do it.
 
I do own and know how to use a multimeter, been doing some repairs on smaller less complicated electronics (usually car audio and some kitchen appliances :D)
Will get the manuals from ak and hope I will be capable of dealing with this slightly more complicated piece of art.
At first look I noticed a burned resistor and the transistor it's connected to seems shorted, could this damage the board too?
 

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FreekT said:
I do own and know how to use a multimeter, been doing some repairs on smaller less complicated electronics (usually car audio and some kitchen appliances :D)
Will get the manuals from ak and hope I will be capable of dealing with this slightly more complicated piece of art.
At first look I noticed a burned resistor and the transistor it's connected to seems shorted, could this damage the board too?
Click to expand...

Unscrew the two outputs from there sockets so you can eyeball the printed side. While you have the outputs removed check them with your meter.
 
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BTW The free online manuals do not cover the CA-800II nor the CA-800 euro model. There is definitely a different layout on the main amplifier boards.
 
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Changed all main transistors and the burned resistor on the main board and the two huge main capacitors :banana:
The amp has been working (both channels) for about 2 hours perfectly at about 30% output :music:, then there was a loud hum and a pop. Now there's nothing... again :tears:
Maybe it's better to have a professional fix this thing before I get even more frustrated and throw it out of a window
 
FreekT said:
Changed all main transistors and the burned resistor on the main board and the two huge main capacitors :banana:
The amp has been working (both channels) for about 2 hours perfectly at about 30% output :music:, then there was a loud hum and a pop. Now there's nothing... again :tears:
Maybe it's better to have a professional fix this thing before I get even more frustrated and throw it out of a window
Click to expand...
:scratch2: Probably the best course of action.
Maybe it's better to have a professional fix this thing
Click to expand...
 
You need to dismantle and clean the operation switch (the Class A) switch. Take your time- it will need to be removed from the pcb and carefully disassembled and the contacts polished. The operation switch has a central multipole switch that changes the bias for class A/AB and if dirty or intermittent, it can take out the amp.

As only one channel has died, it is unlikely to be the rail microswitches, but they should be replaced.

Let me know how you go.

John
 
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