Tektronics TDS320 Sec/Div knob not working - bad encoder?

[TheForgottenKing]

Hello everyone,

I recently purchased a TDS320 for $50. Quite a good price for what it is, and it is mostly working well.

The only issue I seem to have is that the horizontal adjustment knob doesn't do anything. I'm not sure if I'm just using it wrong (this is my first time using an oscilloscope), but it seems to just be dead.

What are my next steps? I've read with other models the best move is to attempt cleaning it, but is it possible to replace the encoder if needed?

Thanks.

[TheForgottenKing]

Update for anyone who finds this thread:

The metal tabs that contact the encoder were corroded and broken off, so I cleaned what remained, made a soft edge, and bent them to make contact with the PCB. This mostly resolved the issue. Sometimes the dials miss a turn or double up but this seems a tuning issue that can be resolved and it doesn't happen often.