Machine tool CRT Problem

[Rod Ouellette]

Today the green monocrome crt on my 16 year old press brake began
malfunctioning
The field of the screen, which is normaly black, is now light green with
with steady lines
that fan out from a point about 24 inches off the upper right hand corner,
the upper most
line is nearly horizontal, the lines are closer together at the top of the
screen.
There is also some flickering going on.

The moniter was made in Europe by BARCO, the crt is a PHILIPS M42-307GH

Monday I will call a TV repair shop, hopefully they will be able to send
someone out.
In the meantime I am hoping someone in this news group might have some ideas
or
explanation.

Thanks in advance
Rod

 

[Arthur Jernberg]

Sounds like you are describing a raster with retrace lines running diagnoal.
Loss of video signal, problems in the g2 bias supply, or even a fault in the
crt can cause this problem. The tech should be able to diagnose the
situation once on site.

 

[Vector Viper]

Today the green monocrome crt on my 16 year old press brake began
malfunctioning
The field of the screen, which is normaly black, is now light green with
with steady lines
that fan out from a point about 24 inches off the upper right hand corner,
the upper most
line is nearly horizontal, the lines are closer together at the top of the
screen.
There is also some flickering going on.

The moniter was made in Europe by BARCO, the crt is a PHILIPS M42-307GH

Monday I will call a TV repair shop, hopefully they will be able to send
someone out.
In the meantime I am hoping someone in this news group might have some ideas
or
explanation.

I have seen TV sets do this (too bright with retrace lines; sometimes bright
on 1 side,
dark on the other) The cap on the power supply going to the output
transistor could be bad.
Usually 10uf, 200v or so...

Viper

 

[Tom MacIntyre]

I have seen TV sets do this (too bright with retrace lines; sometimes bright
on 1 side,
dark on the other) The cap on the power supply going to the output
transistor could be bad.
Usually 10uf, 200v or so...

Wouldn't that actually be the supply for the CRT drivers, and usually
a 250 volt or so capacitor?

Tom