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Old 21st March 2008, 03:21 PM   #1
john65b is online now john65b  United States
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Default Hafler 945 Preamp Issues

Hey all,

I fixed a friends amp the other day and in lieu of payment he gave me a broken Hafler 945 Preamp/Tuner.

Theres a Relay on the preamp board that went bad - I could tap it a few times and the channels would come in fine. I replaced that (12v coil) relay and all was good, but I noticed the balance is tripped up. I have the checked the mono button, and when on, the balance pot has no effect.

But when off, I turn the balance pot all the way to one side, both channels just get a bit fainter.

When I unplug one channel from the inputs, only that channel works as it should.

Seems I may have tripped something up on the balance replacing the relay. But then again it may have been an issue all along and have nothing to do with the relay.

I have also scrubbed down the preamp and PS boards with Alcohol to clean it, and replace the main PS caps...

Anyone have a schematic of the Hafler 945 preamp or know what could be an issues here??
All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian
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