I fixed the foot switch for my Quad!!

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16Bit

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I wanted to post this to try to help anyone who is having a similar problem with their Quad Preamp.

I found an FU-2 foot switch on an online auction site, and when I got it home I noticed that it had a similar problem that a lot of other people have had; when a button was pressed, all the LEDs on the preamp and the foot switch itself lit up at the same time and the channels wouldn’t change.

I traced the problem down to a faulty 74165 chip and a broken leg on one of the big disc capacitors. I found replacement IC chips on eBay, and when I popped the new one in, it worked like a champ. I also gained a little bit of insight on the signal path from studying the not-so-great schematic and doing some voltage measurements on my own. If anyone has questions, feel free to ask!
 
Thanks. I have a couple of those. I might refer back to this if I should ever incur such trouble. By the way- There once was a time when I yanked the cable from a Quad footswitch to effect an emergency repair on the footswitch of a MkIV.
 

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