Hello all, guenthert and Tomorokoshi many thanks, for your notes.
The machine just arrived yesterday, was carefully packed and basically works to spec,
Inside very dirty and dusty, no rework or noticeably bad parts, all capacitors seem fine.
Current control is normal pot, will replace with Beckman Helipot 1K
Meter bezel slightly cracked
Vernier voltage dial on right was scratchy, used IPA 99% and contact cleaner.
I will use high pressure air to blow out dust and wash the PCB with IPA 90%
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The 10s thumbwheel dial on left has the + button broken off about 1/2 way inside. If I use a small tool, I can poke the dial to increment up.
All other thumbwheels are Ok and voltage is accurate.
The thumbwheel seems hard to source an exact replacement, i believe its IDEC and custom made for HP.
Insted of 3D, I propose:
use black polycarbonate or delrin rod stock, machine to the 0.100 x 0.300 button dimension. Cut to legnth and drill small hole in end.
Take a needle, heat in flame and push into broken button end, and into the new machined button.
Another source of the button can be a plastic glasses frame sidepiece with center metal rod.
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I have the manuals and HP Tech Notes article, testing the AC noise, load reg, and accuracy, I can only marvel at theis great analog design.
Open to your comments,
Kind Regards,
Jon