Hello, everyone:
I have acquired a Tektronix 475 scope (Option 4, with DM43), advertised as "working".
Good news - it does display a base trace, and does trigger (sort of) off of the internal calibrator.
The bad news - everything else. Here is what I am experiencing:
- The trace, when displayed, is extremely jittery, and floats up, down, left, right, or even running left to right
- A slightest touch of ANY control results in triggering being lost, and trace disappearing in a random location. Takes some bumping on the case and A trigger level control rotation to bring the traces back... For a bit.
- No matter what I do, the trace is rather thick, even when "in focus"
- DMM displays garbage numbers, and zeroing works only one time out of 50, if that
Since I am very new to this, what would be the proper troubleshooting/repair sequence? DeoxIT controls and switches? Reseat transistors and ICs? Check the voltages per Service manual afterwards? I hope some of you have seen these symptoms before, so maybe it is something more basic?
Any advice of where to start would be greatly appreciated.
Dmitri