Viewsonic E651 wont stay in focus

[tom_mc_h]

I have a viewsonic E651 monitor that will not stay in focus. I can
adjust the focus and all is fine... for a few minutes. Then it looks
like it is underwater. Anybody have an idea of the cause/cure for
this? I have a schematic if I just knew what to look for. Thanks

Tom.

 

[Jerry G.]

Most of the time, this type of fault is in the high voltage multiplier
module. Usually this is part of the flyback assy. It can also be the CRT
itself is going defective. Use a high voltage probe, and monitor the
voltage at the focus grid of the CRT, and also do some monitoring of the
high voltage at the anode of the CRT.

On the CRT board, you may have high voltage bypass caps, and some resistors
in the focus circuit. You can replace these parts to test. Considering the
voltages used, these parts may test okay when using an ohm meter. Most of
the time it is the high voltage multiplier (as I first indicated).

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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"tom_mc_h" <tom_mc_h@yahoo.com> wrote in message
news:f364525f.0404071831.5b195288@posting.google.com...
I have a viewsonic E651 monitor that will not stay in focus. I can
adjust the focus and all is fine... for a few minutes. Then it looks
like it is underwater. Anybody have an idea of the cause/cure for
this? I have a schematic if I just knew what to look for. Thanks

Tom.