[time-nuts] 5371A CRT problem

[John Day]

New CRT's for many of that era of HP instrument 
can be had pretty economically too.

If the raster moves around rather jerkily then 
give the unit a good suck out with a vacumn 
cleaner! Use a nice clean dry toothbrush to look 
for collected gunge particularly around the spark 
gaps on the CRT socket board and the yoke 
assembly. These problems are not uncommon in 
things like the 8920's and the like.

John


At 01:05 PM 6/23/2006, you wrote:



>Hi Steve,
>          I have a 72A and was wondering about the
>same thing. My unit works well, but the display
>looks weak. The raster moves around sometimes. If
>the CRT itself is bad, those can be had used from
>various surplus tube dealers at probably not too big a hit.
>          There is a blanking control that hides
>the screen and blanks it for security purposes. Did you enable that? Check.
>          Doug K6JEY.
>
>
>At 09:50 AM 6/23/2006, you wrote:
> >After a few weeks of inactivity, I recently
> >powered up my HP 5371A and discovered the
> >display is not working. Everything else is
> >working, and I can print the results that
> >normally appear on-screen. I've checked the
> >supply voltages to the CRT driver card A17, and
> >the horizontal sync, vertical sync, and video
> >signals are all present going into A17. I can
> >see the CRT filament glowing. Next step is to
> >check the CRT anode voltage, and the deflection
> >signals at the CRT pins. Does anyone have an
> >idea what they should be? The service manual
> >skips any circuit description or schematic of
> >A17 and says if the CRT circuits are suspect,
> >replace the A17 CRT Driver Board and CRT as an
> >assembly. That assembly is no longer available,
> >and would certainly not have been available at a
> >hobbyist price at any rate. If I can't come up
> >with a schematic, my choices are to look for a
> >parts unit, or bite the bullet and go GPIB. Does
> >anyone know of a parts unit available? Thanks,
> >Steve, WBØDBS
> >_______________________________________________
> >time-nuts mailing list time-nuts at febo.com
> >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
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