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Sean Borton (codamedia)
Username: codamedia

Registered: 03-2014
Posted on Tuesday, March 18, 2014 - 01:45 pm:   

This is on a 212 Sixty Five Chassis #2475-65
SS Phase Inverter. (from 1979)

I suspect I have a failing IC at the start of the normal channel (IC1). When I turn up the volume (on the normal channel) with nothing plugged in, I can hear some interference, yet when I turn up the Reverb / Vibrato channel - it is very quiet.

After reading a few other posts, it was suggested to move IC5 (reverb driver) to the IC1 position. How do you remove these IC's on the 2475-65? They are the circular LM307H but appear to be on a riser or socket... Do they pull out like the later models with standard looking chips - or do I have to unsolder them from the bottom?
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Tuesday, March 18, 2014 - 02:56 pm:   

They are in sockets. Pull gently. If they break, you will have a hell of a time finding replacements. Most people are using brown dog adapters and using contemporary 8 pin IC's with the socket adapters. Make SURE you orient yourself with HOW they go in the sockets(direction) Mike
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Sean (codamedia)
Username: codamedia

Registered: 03-2014
Posted on Tuesday, March 18, 2014 - 03:45 pm:   

Thanks for the info Mike.. I thought they were in a socket but didn't want to tug too hard until I new for sure...

Out of curiosity, are those TO-99 sockets?
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Wednesday, March 19, 2014 - 09:17 am:   

Yes.

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