Author Topic: HP probe power connector replacement? / HP 180AR restoration followup  (Read 1042 times)

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Offline MCRodrigues

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  • Posts: 12
  • Country: pt
    • Miguel Rodrigues
While restoring my HP 180AR CRO I noticed that the 1802A plugin only has 50Ohm low impedance input. I do not have the adequate probes for it and unfortunately is not economically viable to just buy a pair of active probes, for such ridiculously expensive shipping costs...

So I'm going to try make an high impedance active probe adapter similar to those  HP 1124A, using a buffer op amp.
There is this problem that the probe power is not a standard connector. Its the 3 pin connector described on this post:

So buying two male connectors for the adapters is even worse than buying the probes...
I noticed that the probe power connectors have almost the same diameter as the mini-XLR.
See the male chassis mount connector:

Would it be viable to just replace the connectors and keeping the originals for a adapter to compatible devices? Or should instead create a dedicated power supply for it?

By the way for those that where following the my repair:
IT'S ALIVE!! Completelly uncalibrated but alive!  ;D

Will need to make some repairs:
- The vertical amplifier (1802A) does not give the right amplitude from the scope calibrator. (Requires calibration or missing the probes?)
- The time base (1822A) triggers on all inputs except the internal.
- At the time base, the main seep vernier knob works, but the default position switch is stuck and does not light up the uncal lamp.
- The Horizontal positioning in the mainframe saturates before the last three graticules of the screen (Main issue!  :-\)

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