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Yamaha C-4 Preamp Recap

avionic said:
Re-measure these voltages please.
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Reinstalled TR195, 197, 199, 201, 203 & 205. Don't see any obvious smoking like before...but not sure what's changed between the last time it smoked? Left it on for a few minutes. Front power lights stay on.

Remeasured
TR626 E: -37.5V
TR627 E: 30V
 
Install TR634..And re-measure
TR626 E:
TR627 E:

If possible.
 
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avionic said:
Install TR632 and 633.. And re-measure
TR626 E:
TR627 E:
Click to expand...
Re-installed TR632 & 633. Remeasuring

TR626 E: -29.7V
TR627 E: 30V

Front power lights are staying on! No crowbar circuit issue! :) Cheers and thank you!

I'm still not sure what exactly we did other than remove transistors, check them and reinstall. There were the couple of resistors that burnt up and I replaced, but still kind of mysterious how it's working now?!! Hoping I don't have intermittent issues going forward.
 
Checking out sound. C4 paired with M4. So far so good!

A bit concerned at first since the left channel was completely missing. After messing with the input switch, I gave it some more force pushing it to Aux and both channels are coming through now. I may have to go back in and double check that input switch. Seen a few threads here that might come in handy.
 
Jake O Bob said:
A bit concerned at first since the left channel was completely missing. After messing with the input switch, I gave it some more force pushing it to Aux and both channels are coming through now. I may have to go back in and double check that input switch.
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The switch could just be dirty or have a cracked solder connection.
 
avionic said:
2SA673 sub


https://www.mouser.com/ProductDetail/onsemi-Fairchild/KSA1013YTA?qs=ljbEvF4DwON6KcAiegZDyA== sub

Is your 2SA673 shaped like and " outhouse " ?
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Just found this while searching 2SA673, what is the significance of the outhouse shape? Just a manufacturing prerogative? Are the pinouts reversed on all of these? They are presently installed contrary to the normal TO-92. Are they still considered a TO-92? Apologies for the inquiry on an old post but 8ve been searching for this very topic unsuccessfully for some time until now. Many thanks for your insight.
CJ
 
CJ Sevilla said:
Just found this while searching 2SA673, what is the significance of the outhouse shape? Just a manufacturing prerogative? Are the pinouts reversed on all of these? They are presently installed contrary to the normal TO-92. Are they still considered a TO-92? Apologies for the inquiry on an old post but 8ve been searching for this very topic unsuccessfully for some time until now. Many thanks for your insight.
CJ
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I got trigger happy when I finally found the "outhouse" term and sent the message. I then thought it may have served me well to have done a little more scrolling on this individual thread. Now I feel silly. Please disregard the earlier query.
 
avionic said:
So is your C-4 all squared away?
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Actually it's a CR-1020 I'm working on. Going through the entirety of the power supply and a few other issues. Progress is slow as work at UPS is wide open now this time of the year. Lot of $ to be made and a local has a B-1 for sale on the marketplace. Asking $3500. Won't go that high but I absolutely love my B-2, C-2 set. Thinking on it real hard. What are your thoughts?
 
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