Hi all,
From the first post in the Repair thread:
http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf
The clicking sounds like a SMPS failing to start. Does it use a SMPS?
Start digging in the PSU's LV & HV
Any Tantalum caps on the PCB's?
Yes, SMPS it is but I haven't examined the PSU thoroughly yet.
Thanks for the tek-tutorial, this is very helpful indeed! And this way the circle closes again since this story began in the first place when I was trying to fix an old Tek-465 that I had lying around for some time. While trying to do so my HP54502 died on me as well and now I am falling back to a Tek-5403 (which is probably older than me) in order to fix them both
Embarrassing not having read the repair-thread first, I rather searched for keywords and followed this thread due to a matching post...
Of course this post should go into the Repair-Section as well
It's interesting to learn that the 545xx series uses the same power supplies.
I can only tell for the 54502A and the PSU parts number is P/N 0950-1879 (Boschert Type 700040-01 Rev. K)
It looks quite similar to the schematic of the HP-54503A that wn1fju provided.
Bottom line: I finally bought two Meanwell switching supplies and built my own power supply for the HP 53310A. Works like a champ, draws only about 80 watts instead of Boschert's 120 watts and cost me less than fifty bucks.
This could be a second solution of course, but I will throw at least one try at fixing this one.
A first reading of the power transistor housing looks like the attached scope screenshot.
Settings were: 10:1 probe, x: 2ms/div, y: 5V/div, out-dc
There are glitches about 3-5 times per second.
Update (if only for personal use):
Switching the scope on today just cured the malfunction for about 10 minutes. All supply voltages back to normal and a self-test turned out successful. Hooked up a scope to the PSU's power transistor for comparison and the ramp-up in the wave-form covers only a third of the overall signal swing instead of more than half when malfunctioning. Let it sit there running for a while until the PSU got a hick-up again, switching on and off for a few times.
Eventually the scope will turn on again but showing a black screen. Checking the PSU output voltages gives correct readings for the +12V, +3.5V and +5.2V rails, while failing on -12V and -5.2V, referring to the service manual.
Thanks everyone so far, any feedback is valuable!
vanhouten