| Electronics > Repair |
| HP 54502A repair once again |
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| vanhouten:
Looks neat! The assembly appears to be almost identical to the 54502A. Here is what I have come up with to jump-start my board in order to verify it still somehow working ;D As Smith suggested it would probably be too much of a pain to fix this thing at home, as I have to. I guess I will get over being such a lousy sport quite soon and realize once more that cheating is just another way to win. Thanks for all the help so far, guys! |
| vanhouten:
Hi guys, finally back from holidays and meanwhile the PSU's arrived, so time to get back to work... @wn1fju: could you quickly comment on how you did the rewiring of the MeanWells to the ribbon-cable? The +V of the right supply is hooked up to the COM-rail of the left supply in order to get the required -5V. I can see from the picture that you inserted two diodes as well, yet the wiring is a bit tangled, so I can't figure out to which terminals they actually attach. Thanks in advance for any hints! Cheers, vanhouten |
| wn1fju:
For vanhouten: Attached is a zoomed in picture of the wiring around the terminal blocks. The big supply on the left supplies the 5, 12 and -12 and the little supply at the top does the -5. You are correct in that the little supply V+ goes to ground and V- then becomes the negative voltage. The ribbon cable had 20 wires and I split pins 1-10 to run to the lower terminal strip (from right to left) and pins 11-20 to the upper terminal strip (right to left). You can see on the masking tape the legend that I used for the terminals. I simply jumpered along wherever I needed to pick up the proper voltage. The only other thing I did was to run double wires from the left supply for +5 and G. The two diodes pick up one of the 5V connections and route it to the proper 3.5V terminal. It later turned out that I didn't require 3.5V, but I left the diodes in. My choice of wiring is certainly not the only way to do it. Just make sure to leave the end of the 20 pin ribbon cable disconnected from the mainboard when you first test the supplies in case you made a mistake! In a perfect world, I would have removed the 20-pin connector from the Boeschert supply and figured out how to mount and use that. I still have a queasy feeling that all my wires are radiating switching noise and compromising the noise floor of the HP 53310A. I'd be interested in seeing if you suffer any ill effects with your scope. |
| vanhouten:
Thanks so much for taking your time! I will see how it works out for me and give feedback as things go on. I think this is probably the most convenient way for anyone having trouble with this series of scopes and there might be still quite a few of them around. |
| vanhouten:
Hi again, unfortunately installing the replacement supplies did not cure my scope. Power-up is flawless, yet in selftest I'm being told that the AD/DA section is broken somehow (see attached picture). This doesn't look all too good to me and I am close to giving up on this machine... what a shame. Did anyone have a similar problem with this scope and in the best case an idea where to go from here? Best regards, vanhouten |
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