Yamaha C1-preamp --Vfets

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Hello,
I have a not working Yamaha C1-preamp, I need for repair following parts ; transistors, "V-FETS" ??? 2SJ24 and 2SK78 ,
Who knows where I can find theme, or who knows are this items also used in other types of amps Yamaha or Sony , so I can take out and repair my rare Yamaha C1
Thanks for helping
 
About the only place you'll find the parts you need are on/from another C-1 preamp.

Even if you had replacement parts, you or a qualified tech (which are becoming harder to find) will need to troubleshoot and find out what caused the v-fets to failed. V-fet failure is usually a symptom, not a cause, and the C-1 is quite complex to work on.
 
Hello Bille,
thanks for answer,
Yes , I know it's a very complex preamp, but I have good tech found, he already repaired my Onkyo M-510 , and he already fixed my C1, exept the V-fets who we can't find till now, I had a little hope that those fets are also used in for exemple a C2 or other type,,,,,,
Best regards
Luc
 
Hello Anastanef ,
sorry for late answer , but I didn't visit the site till now , I've tryed to contact Yamaha all over the world,the answer was still the same, there are no spare-parts available anymore , the only way to repair and to find parts is finding another C1 , the most parts are specialy produced for the C1 and are not used in any other amp , exept the B1-Poweramp which belong together with the C1 ,, or to find old stock by a local dealer ,but it's very difficult to find anything , I'm searching for a long time now.
When you should decide to sell your C1 , let me know ,
Friendly regards
Luc - Belgium
 
Unfortunately, there are no sources for the 2SJ24 and 2SK78 except for the C1 itself. These were specially designed for the C1 and it's the only Yamaha commercial amp that used them, similar to other VFETs used in the matching B1 power amp, which are also unique along with several other FETs. Yamaha service network has not had any spares for these since 1988 or thereabouts, so for some 25 years. These were on-order from Yamaha central so services dod not keep them in stock.
 
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