Alright, so I'm not in the clear with this 2247A. I've been busy with other things and had the scope off for about 3 days. Turned it on this morning and noticed the trace was a little noisy without a probe connected and I also noticed a very faint high pitch noise that I haven't heard before. I didn't think much of it but after being on for about 5 minutes, the scope locked up and all of the LEDs in the horizontal section were off and all controls were unresponsive. When I turned the scope off, I noticed the screen displayed a little square that disappears, almost as if something was being discharged. I really don't know how I can explain it but usually when I turn the scope off, the display just turns off. I noticed this screen aberration when turning the scope off when I initially observed the lockup/error problem.
When I turned it back on, the high pitched noise was no longer present and it hasn't locked up again. The high pitched noise would point to something in SMPS, or at least I would think. Any idea how I can troubleshoot this further? My though was to leave the scope off for another few days , take the chassis out before restarting it and then if I get it to fail, check the voltages and see if anything looks to be out of spec. It seems like the scope doesn't like a cold, cold start and the failure disappears after the scope stays on for a bit. Almost seems like one (or more) of the caps are borderline.
Thoughts?
