Help! Restoring a preamp Yamaha CP70b

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peterkohlmetzmoller
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Re: Help! Restoring a preamp Yamaha CP70b

Post by peterkohlmetzmoller » Thu Feb 09, 2017 10:03 pm

FET's came home yesterday from Germany, new old stock.
I couldn't resist so I took a chance and changed the FET's; and guess what, everything is in working order again! :D
They indeed where the problem. Changed all of them, took 20 minutes disassembling and everything.

Maybe it was a c**p shot, but I had a feeling they where bad, since the one on the power distribution board was bad in the beginning, and by looking at the service manual, it seemed like they very much are the centerpiece of the preamp.

So for future problems for other cp70/80 owners with bad pre-amps; check voltages and check/change the FET's, and hope you find this post :-)

Thank you so much guys for second opinions and advising me!
All the best greetings from Peter

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madtheory
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Re: Help! Restoring a preamp Yamaha CP70b

Post by madtheory » Sat Feb 11, 2017 11:56 am

Good news :)

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