Ceronix CRT monitor repair guide

[gametech2]

Hi all.

I have exausted  all my knowledge and experience/training from years ago on this Ceronix1492 monitor with annoying retrace lines that just wont go away.
 The screen voltage will not adjust at pin 8 on the comparator ic.
when you first turn the power on, it has close to 5 volts there, but the instant the system comes up, it begins to drop rapidly, until it is down to around .4 to .5 volts.
 I did some digging around on the ceronix website, and found a linik to a CRT BASED TRAINING Powerpoint  download. I have not read it all yet, but it looks promising.
I thought I would post the link here, in a simple doc format if the system will let me.


GO TO THIS WEBSITE:

https://www.ceronix.com/

In the middle of the page click on " support  Get Support "

https://www.ceronix.com/support/

Select  " Technical Workshops "

https://www.ceronix.com/technical-workshops/

About halfway down, look for "" To download the Technical Workshop Powerpoint file click on the link below. A fast internet connection is recommended for the 87 MB file. ""

The first file in BOLD Blue is " CRT Based Training "

This is a link to download the power point presentation to guide you through testing procedures on these

CRT based monitors.   

When you click on this link, it will launch the download, and save the file to your computer.

Good reference material for new and old technicians.

There is a lot of good reading there on monitors, with fairly good pic's, and explanations on the circuitry and component replacements to help cure common problems.  And at the end they have info on replacing the monitor with a flatscreen LCD monitor with harness and some wiring pinouts.

.........jb

.........jb

[gametech2]

HOPEFULLY this will help some of us old guys troubleshoot these monitor problems!!

[Chris-socal]

I call that the .6v problem! Lol
It “can” be an indication that the flyback is on its way out. That reading comes off a passive coil on the flyback.
There are other components that can cause that though. One of the PRA boards having a broken connection can cause all kinds of related issues in the video circuit.

I will have to look at that training video. Have you indulged in the troubleshooting section of the manual?

Chris

[gametech2]

Hi Chris,
sorry for the delayed response!
Lately I seem to have 0 % time for troubleshooting this monitor.
I replaced the large caps, no change last time I was in there.
I have gone through the troubleshooting section, just cant seem to put my finger on what is the problem.
I can monitor  pin 8 on the comparator ic, with the power completely off, watch the meter as I flip on the switch on the variable power supply, and it climbs rapidly to the approximate 5 volts, and as soon as the set loads up, it INSTANTLY begins dropping, till it is down to nothing {around a half volt}. This tells me the comparator is doing its job initially, but something is wrong either on the positive, or negative inputs.
I just have not had proper bench time to narrow it down to a single component!  My projects are far and wide, and I just today got my Granddaughter off to college for her second year art. BUSY BUSY BUSY!!!
But I am determined to find the culprit..............................jb

[Chris-socal]

It isn’t uncommon for the monitor to work perfectly fine with the low reading. The manual explains how they get that reading, its possible one of the resistors or diodes coming from tne flyback is not doing its thing….or the flyback is on its way out.

[gametech2]

yea, I fought this battle way back in the 80's quite a bit, it seems like it was always a diode leaky, or just plain goofy, along with a burnt resistor and maybe a leaky non polarized capacitor, and ALWAYS  hard to nail down.
..........jb

[Chris-socal]

Typically I would swap in a known working flyback which would quickly narrow down if the flyback is the problem.