VT101 8085 CPU Fault

Matt Burke matt at 9track.net
Mon Feb 16 19:31:27 CST 2015

On 16/02/2015 20:38, Robert Jarratt wrote:
> What other tests would you suggest? I do have a capacitance meter to check
> values. I would have desolder them of course. Would you test just the
> electrolytics or all of them? I don't have an insulation tester though. Any
> other tests?
> Regards
> Rob

Check the leakage current using a bench supply (same setup as reforming)
- particularly C321. Leakage here may be causing a DC offset to be
applied to the vertical yoke. If you have no luck here then have a look
at the schematics for the Elston/Digital monitor board in MP00633 or
similar. Expected waveforms are given for some points in the circuit.
Using a scope you may be able to work out where the wobble is coming from.


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