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Yamaha A-960II Problems

R

Rustygunns

New Member
So I recently found my dad's old Yamaha A-960II in the basement, bought some Sansui SP-30s and had some fun. As time went on, each time I powered it on, it would take and longer and longer to "click" on, eventually stopping altogether. I made a thread over in the Yamaha forum asking about it and the problems only got worse. Hopefully I can maybe find some more solutions over here. Here are some pictures of the inside, pictures 2-4 I only recently noticed whatever that stuff is, probably not normal. Also, I'm still learning what a lot of this stuff is so if you possibly try to simplify things as much as you can, it would be appreciated.

Things I have tried:

-Steps 3 and 4 of the manual but I was cut short when testing when I touched the TR331 collector and something shorted out and now the lights don't turn on. I can hear a slight buzzing from the transformer, but that is the only indication of something working
-I checked the fuses, they were fine, got new ones just in case, no luck

Thanks
 
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The brown stuff at the base of the large capacitors is assembly glue. Unless you see corrosion on components in contact with the glue, it isn't a problem. It looks like you shorted the B+ voltage.
 
Need to look at fusible resistors in the regulated power supply. Do you know how to read a schematic ?
 
I have a digital multimeter as well as soldering tools. Not sure about the schematic though, but I could try. What do you suggest?
 
Insulate your test probes all but the very pointed tips with electrical tape or heat shrink tubing. Don't need anymore sparks.
 
Rustygunns said:
Found them on the schematic, do I have to remove them first?
Click to expand...
No not yet. Can't make any voltage measurements if there out of the circuit.
Can you easily access the bottom soldered connections for those two caps.
 
I was able to get the bottom panel off, but I'm having trouble transferring the location of the caps from the schematic to the physical board. Would it be possible to maybe point some "landmarks" as to where they would be?
 
31521056525_d7841f5491_b.jpg
The two large missing parts in this photo

Photo borrowed from.Nashou66..http://audiokarma.org/forums/index.php?threads/yamaha-a-960-troubles.717452/page-5#post-10127239
 
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If your unit has that glue all over it like this photo.Notice how its corroded the jumper wires and just about everything else it comes in contact with.That glues needs to be erradicated and corrosion addressed.
 
Tested the caps, no where near what you said they should be at. Should I maybe remove them, clean up the glue/corrosion, try again?
 
Was doing this:
avionic said:
OP look through the manuals and see if you can make any sense of it. See if you can locate the two large caps C345 and C346. Measure the DC voltage acrossed each one.Should be close to + 60 on one and -60 on the other.
Click to expand...

Measured no higher than 3v on either of them.
 
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