Hello and thank you all for chiming in on my topic; all excellent suggestions. I have been “out” since I submitted that, so I just now was able to sit down and read through the last days digests. This is probably the 10th HP5328A that I have had to fix the PSU on, so it shouldn’t be such uncharted territory! Funny thing about it; as I sort of eluded to and am now seeing 100% is that virtually everything is shorted “dead” to ground, making any path from where the transformer leads the voltages out forward to a 0Ω reading - that is why this is such a PITA; I was and still am having a hard time finding a starting point with ANYTHING that is not shorted to ground… I pulled all of the fuses and forgot that still allowed the 4500uF cap to see potential and had to listen to it sizzle. (How dumb was that???) Luckily I have a bunch of spares here to replace it with. I am guessing with how absolutely shorted out everything is, this is merely a case of me not seeing the forest for the trees; as something shorting every bit of the PSU shouldn’t be that hard to find, darn it! I am going to pull the schematics and flow chart and go through everything one by one to try and find the “end of the line” culprit (which there may be several in this situation) that are allowing a freeway like short to ground potential… I wanted to use one of the bench PSU’s too to unravel this, but a quick run through with the 196 in the Ω range tells me all that will happen is it will see the same short and current over limit will shut it down; just as the fuses and everything else failed when I plugged the unit in. Thanks for all of the suggestions. As mentioned, I have fixed nearly a dozen of these and never run into one this out of whack; which is why I posted. The offer to just swap for a working PSU board is tempting, but I really cannot afford anything at the moment and I should have nearly all of the components on this PSU laying around either in the parts bins or available from a scavenger board… Thanks again everyone, I will keep everyone up to date; it likely will be funny when I find the problem as something tells me it has to be a pretty obvious issue to short everything out together… It also looks as if someone has already swapped PSU boards in this judging by the solder joints and such as well as the coloration of the board is a slightly different color too…
Warm regards, Douglas M. Wire, GED, FNA, _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
