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SE/30 UA9 question regarding pin 1

mjhagen

Active member
Am I correct in assuming that pin 1 (and pin 8 ) is not connected? In trying to locate an issue with my sound I decided to cleanup this part of the board and the pads for pin 1 and 8 came off.

Looking at the LB schematics I don't see them mentioned, and looking at the datasheet for TL071B I see pin 8 has NC, so I think I'm safe there, but pin 1 has Offset N1 next to it and I don't know what that means.

 

apm

Well-known member
Pin 1 and pin 8 are generally NC on most common single op-amps, and if they were used it would be for minor offset adjustment. I think you can safely ignore the missing pads.

From memory, sound issues can come from UB10 and UB11 (Sony sound chips) as their location makes them prone to being affected by cap goo.

 

mjhagen

Active member
Thanks for your reply @apm, I'll take another look at those ICs. Their contacts seemed ok, but I'll do a few more thorough measurements. I'm getting the idea this board is more corroded than it seemed visually. @techknight gave me a few ideas with his recent Mac Portable troubleshooting vid.

 
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