Pioneer A-60 Rebuild-Restore

I've been playing it for awhile, looks like I totally lost the left channel now!

Edit that, It comes back when it cools down a bit...
 
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Latest update, I found that one of the multi wire cables had pulled out a bit on one side. Placed it back in and tried the amp again and voila! I have been playing it for the last hour at pretty high volume and it is singing! It does really well with my Thiel 04a's. Total recap has really brought it to life. I'm really impressed with the phono section!

I'm pleased as punch!!!:blob8:
 
laatsch55 said:
Good deal, a nice feeling isn't it??
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Yes! It was for a while! Left channel went out again... it's only when it gets hot. It played for a hour or so before I put the cover back on.. then it went out again. I have some Freeze coming, hopefully that will solve it!
 
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Ok, are the heatsinks for that side getting hotter than the other??
 
laatsch55 said:
Ok, are the heatsinks for that side getting hotter than the other??
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It doesn't feel like it to me. However there were definite signs of it over heating before on the left side! Especially by a couple of the outputs and one of the big resistors.
 
Hang in there man, looks like your almost there!!
 
The Elektrotanya pdf isn't too bad...it's the same one that's on Hifiengine.
 
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You're welcome! Hope that helps you.
 
Well this one is a stumper. Left channel still going out when amp warms up only very infrequently. Strange one. One time I tried the freeze spray on one particular transistor and the left channel came back but every other time it didn't.
 
laatsch55 said:
Did you change out that transistor?
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Nope, I don't have one so it is a mouser order. Waiting to see what else I should get as I hate paying the shipping for just one or two things! It's a 2sc2238 and the complement is a 2sa968. From a search the recommended replacements are
"757-2SA1837(F,M) pnp to-220 bce 230v 1a 20w 70mhz 100-320hfe 70mhz nsa driver
757-2SC4793(F,M) npn to-220 bce 230v 1a 20w 100mhz 100-320hfe 100mhz nsa driver
or (** preferred, due to the extra amp of drive **)
757-2SA1930(Q,M) pnp to-220 bce 180v 2a 20w 200mhz 50-320hfe 200mhz nsa driver
757-2SC5171(Q,M) npn to-220 bce 180v 2a 20w 200mhz 50-320hfe 200mhz nsa drive"

as per MarktheFixer...

I wanted to get the preferred but 2sc5171's aren't available...
Also would like to find what the replacements for the CTU-2S's are. They are a dual diode in TO-220 package. Would also like to find out replacements for the outputs. They are 2sa1294/2sc3263 complimentary pair.
 
Well after the left channel finally died again I tested the emitters and Q525 went dead. It's a 2sc3263

Wow, Digikey has them in stock!
 
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