Yamaha CA-2010 problem with power amplifier

stozek2000

New Member
Hello;
I have a Yamaha CA-2000 amplifier (CA-2010). There is a problem with the left channel. I hope to get help in this forum. The protection relay does not work. I checked all the power supply voltages, They're ok. I detected a problem in the left channel.
When I connect the amplifier through the bulb it starts to blink.
Look at the movie:

I noticed that this reaction is caused by a resistor fuse FR301 which I marked on the schematic.
I also found something else. When I disconnect any of the power branches ( +/-68; +/-27 ) the problem disappears.
Look at the movie:

The light bulb is my protection against high current. In no case does the protection relay not work. I checked all the transistors in the channel with my meter. I also checked all ceramic capacitors. They are all working. I replaced all electrolytic capacitors. You can help me with my amplifier problem? How can I find the cause of the + 68V branch overload? I add a schematic with marked FR301

Bez tytułu.jpg

Sorry for my English, I hope you understand me
 

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  • yamaha_ca-2010_sch.pdf
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What do you mean by "reaction caused by FR301"?
Is FR301 blown? If so, did you replace it?

If you disconnect the left channel, will the bulb dim normally, and will the protection relay click on?

Your English is fine, we just need some more information.
 
I was slightly puzzled by this. I'm not sure that removing the +B then -B rails/wires in turn proves much. OK, the bulb no longer pulses
but you have removed one rails, so the other rail "floods" the amp with eg -B voltage effectively shutting it down(?). Seems like you have
a failed component that is tripping protection. While on DBT a good start would be to measure the voltages at the transistor base of
the outputs, drivers, bias TR,,,
 
what wattage is the lamp ?
and what is that black box ?
and why did you break something with your screwdriver ?
 
left and right channels use same numbering scheme . i guess if you found the other r301 and yanked it out the bulb would dim .
please disregard if mains power supply is adequate with a high enough wattage lamp .. vol down no input . no speaker loads .
 
sking for help, getting help and then....

....nothing.

See that a lot lately :rolleyes:
+1, time better spent working on a Sansui 5050. Previous einstein replaced 1x2A and 1x5A fuses with 20A fuses.
Guess he was tired of replacing fuses, candidate for a darwin award?
 
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