S
Shaun Davy
Guest
Hi,
I have been given a 14in Compaq monitor model No. 473 that has phillips
internals and gives a chassis No. of CM0200.
The Problem with this monitor is that after the unit is switched on the
focus and brightness drift till after an hour or so the screen is
unreadable.
Have monitored the voltages on the CRT socket on the neck board and most
voltages drift slighty but G2 varies from 58 - 66V in 20 mins or so, as i am
guessing is the focus (DMM cant measure that higher volts). Also the heater
voltage was only around the 5.90V mark???
Have monitored the voltages on the flyback and there is one voltage that
moves with brightness and contrast, that seems to drop from 6.5V down to
anywhere around 3V as the screen blurs.
Have tried going around with freeze spray and can get the voltage on the
flyback to come back up a little with spaying it on some components around
the flyback but cant seem to isolate it down to a component. I have already
replaced all the electro cap's in that section.
Also sometimes when spaying components with freeze spray the reading on the
flyback will fluctuate a fair amount and the screen brightness and size
varies with it.
Can anybody please point me in the right direction.
I have no probs with electronics, i have just never worked on tv/monitors
very much
Thanks
Shaun
I have been given a 14in Compaq monitor model No. 473 that has phillips
internals and gives a chassis No. of CM0200.
The Problem with this monitor is that after the unit is switched on the
focus and brightness drift till after an hour or so the screen is
unreadable.
Have monitored the voltages on the CRT socket on the neck board and most
voltages drift slighty but G2 varies from 58 - 66V in 20 mins or so, as i am
guessing is the focus (DMM cant measure that higher volts). Also the heater
voltage was only around the 5.90V mark???
Have monitored the voltages on the flyback and there is one voltage that
moves with brightness and contrast, that seems to drop from 6.5V down to
anywhere around 3V as the screen blurs.
Have tried going around with freeze spray and can get the voltage on the
flyback to come back up a little with spaying it on some components around
the flyback but cant seem to isolate it down to a component. I have already
replaced all the electro cap's in that section.
Also sometimes when spaying components with freeze spray the reading on the
flyback will fluctuate a fair amount and the screen brightness and size
varies with it.
Can anybody please point me in the right direction.
I have no probs with electronics, i have just never worked on tv/monitors
very much
Thanks
Shaun