Reply to "Lionel 8142-T35 sound board(SOS) repair"

C W BurfleOGR Forum Member

Well, I got the board working again. Unfortunately, I did not go with my original plan to just replace the 100 MFD capacitor with one of the proper size.

Instead, I decided to change the hot transistors first.

I changed the transistors one by one, and briefly tested the board after each one.

So, I changed out all four of the 3-wire transistors - no change.

I installed a new 47 MFD capacitor (correct value) to replace the oversized 470 MFD capacitor that I had installed - no change.

I replaced the 470 MFD capacitor - no change.

I replaced the oversized 100 MFD capacitor that I had installed with the correct sized 22 MFD capacitor. - the board now works.

7/16/1512:51 PM

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