23 April 2019

Distorted readout on Tektronix 7603

I got to use my Tektronix 7603 analog oscilloscope over the weekend and started worrying.

I usually fire it for few minutes to check a signal and then off it goes for weeks. Not long ago, during longer operation, I heard a "clunk!" and with side-vision I saw the CRT display going blank and then back again.

Last weeks the "Trig'd" lamp on the timebase plug-in broke, but it triggers just fine.

Fast-forward to this weekend... when switching vertical plug-ings left-to-right I noticed the Tek was using a different font for readout:

Wait a moment! That's 1970's hardware, it cannot change font!

I am afraid I need to start troubleshooting from the PSU. This calls for a way to see PSU signals, that means I need another oscilloscope.

And dilemma: keep it or let it go? It will hardly sell as a single piece (to be re-capped, the least). I might sell individual plug-ins, 2x 7A18, 7A13, 7B80 (doesn't sweep), 7B53A. Or keep the beast since I can configure it to provide 4 channels at 100 MHz BW.