Re: PS 5010 troubleshooting (no negative, erratical display)


Hi Steve,

interesting... I like this supply and use it quite often. You can even use it to drive and control a transistor's base!

When I first used these PS5004 I thought the display was digitally controlled, but since it was able to show a negative voltage or a bit above 20V I began to doubt. And indeed.

For the alignment I was referring to the fact that alignment of the same 3 pots (zero, fine and coarse) is done several times in different chapters.

FIRST: §2 "Full Scale (R2043) and Fine Span (R2044) Presets"
This comes right after §1 coarse reference adjust (the switch).
A note says this should only be done when the reference IC has been changed. It consists of aligning the pots for a voltage of 6,550 volts.

SECOND: §4 "Zero Output Adjust (R3062)"
There is an instruction of how to connect the PS5004 to the voltmeter that I did not really understand. It says
"Connect the PS 5004 OUTPUT to the digital voltmeter input using a bnc cable and a pair of bnc-to-banana plug adapters. The shield side of the bnc is connected to the PS 5004 OUTPUT terminal, and the voltmeter Low input. The voltmeter guard is driven by the Low input. Connect the patch cable from the PS 5004 OUTPUT terminal to the ground post connector."
Anyone else who finds that substandard in terms of clarity? It looks like a cut&paste mess to me, but did Tektronix already have text processing these days?

THIRD: §§5&6: "Full Scale Adjust (R2043) & Fine Span Adjust (R2044)"
This time you align the same pots as in §2 with reference to the real output (in CAL mode). The pots had to be turned quite a bit (plusminus 2 revolutions) to get the right voltage here. But that means that the preset alginment in §2 was useles... No?

FOURTH: §7 "Full Scale (R2043), Fine Span (R2044), and Zero Output (R3062) Final Adjusts"

This time all three pots are re-aligned with reference to the real output, with the unit in normal RUN mode (not CAL mode). Again, I wonder what the alignments in §§2, 4, 5 & 6 were good for. I could have started the whole alignment right here, skipping the previous steps, couldn't I?
Perhaps not because these alignments interact somewhat, so you would have to repeat the steps in §7 several times if the previous steps haven't been done.

The next steps are for alignment of the DMM and current output. I always end up with a quite precise power supply, the DMM usually shows -0,0001 when at minimum. But thats well within specs...


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