Joe Farr <joe.farr@KCSL.UK.COM> wrote:
> I thought I'd try the list as I can't get a service manual for my Gould
> 4050 Digital Storage Scope and it's developed an annoying fault.
>
> Once it's been switched on for a minute or so, the display starts to
> shrink and then jump back to the correct size. At the same time, the
> traces start moving up and down, left and right. During these 'fits',
> the display brightness seems to fluctuate quite a lot as well. After a
> while it seems to settle down with just the odd burst of trouble every
> now and then.

I'll be there's a bunch of dust inside that's slighty hygroscopic. Each
time you turn it on, the high voltage finds some leakage paths until the
accumulated moisture cooks off.

Try opening it up and cleaning it out thoroughly (and carefully!),
particularly around any high voltage sections. Use compressed air if you
have it.

-- Dave Tweed

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