Ralph Musto

Hi,
First time for me on this forum.....

I have a TDS430A that I am repairing. So far it has just had some SRAM chips replaced and is now passing self test. Nice.

However, three of the four front panel controls have developed a problem. Checking the outputs of the rotary encoders, I can see that some have very low signal levels, less than 2 volts, so not surprising that they don't operate properly.

My main problem now is the lack of schematics to help me check out all supplies are correct.

Can anybody here help me out?  Can't find any 400 series schematics anywhere....

Thanks,
Ralph