Hint on repairing old analog oscilloscope

[Jens Jacobsen]

My old oscilloscope displays some "blur" when using both channels
simultaneously, see picture at

http://www.qxl.dk/form/ViewImage.asp?auctionnr=566862512&curimgvers=0&imgcount=2&rank=2

Is this a leaking capacitor in the chopper circuit or what should I
look for?

The model is an "Advance OS 1000".

 

[Charles]

"Jens Jacobsen" <a.b.renner@gmx.de> wrote in message
news:6d81bfaa-fd6d-475a-a4cf-86ccdf37b07d@k2g2000yql.googlegroups.com...

My old oscilloscope displays some "blur" when using both channels
simultaneously, see picture at

http://www.qxl.dk/form/ViewImage.asp?auctionnr=566862512&curimgvers=0&imgcount=2&rank=2

Is this a leaking capacitor in the chopper circuit or what should I
look for?

Using both channels requires a bit more beam current. If the high voltage
supply is marginal, you will get some "blooming" aka defocusing.

 

[Samuel M. Goldwasser]

"Charles" <charlesschuler@comcast.net> writes:

"Jens Jacobsen" <a.b.renner@gmx.de> wrote in message
news:6d81bfaa-fd6d-475a-a4cf-86ccdf37b07d@k2g2000yql.googlegroups.com...
My old oscilloscope displays some "blur" when using both channels
simultaneously, see picture at

http://www.qxl.dk/form/ViewImage.asp?auctionnr=566862512&curimgvers=0&imgcount=2&rank=2

Is this a leaking capacitor in the chopper circuit or what should I
look for?

Using both channels requires a bit more beam current. If the high voltage
supply is marginal, you will get some "blooming" aka defocusing.

The photo really doesn't look that bad. There will always be a bit
more fuzziness with chopped than with single channel or alt. Do you
know for sure it was better before?

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[N_Cook]

Jens Jacobsen <a.b.renner@gmx.de> wrote in message
news:6d81bfaa-fd6d-475a-a4cf-86ccdf37b07d@k2g2000yql.googlegroups.com...

My old oscilloscope displays some "blur" when using both channels
simultaneously, see picture at


http://www.qxl.dk/form/ViewImage.asp?auctionnr=566862512&curimgvers=0&imgcou

nt=2&rank=2

Is this a leaking capacitor in the chopper circuit or what should I
look for?

The model is an "Advance OS 1000".

Your scope was made about 35 years ago. As long as the traace mixing is
consistent and stable and not intrusive, stay with it until something more
problematic appears.


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