Hey all,
I'm trying to restore a 576 curve tracer. When I turn it on, the trace will go off screen... usually I'm able to move the trace back on screen using the position dials. However, when pressing the "invert", "zero", or "cal" buttons, the display will jitter quickly and then drift around, often settling off screen. I've traced the problem as far back as sources of Q531A/B and Q631A/B. What's curious is the drifting can appear independently on the vertical and horizontal. Sometimes both drift together. Sometimes one drifts. Sometimes the other drifts. The convergence to a steady value appears to be exponential with some jumps when observing the sources of Q531A/B and Q631A/B. The 100V supply and +/-12.5 V supplies seem steady, though reading off the decoupled 12.5 rails shows some twitching. Any ideas what could be going on?
Evan
