Ibm 9525-002

[Tom41]

I have an old IBM 9525-002 CRT monitor that was just in storage for a long time, as a spare in case any of the other computer monitors in the house died. I just connected it up again to see if it still worked, and it seems to be dead.

The first time I powered it up, the LED came on, the tube made its characteristic high-pitched whine, but nothing appeared on the screen - not even the BIOS POST screen! After about 30 seconds, the LED went out and I heard the tube de-energize. Switching power off and on using the front panel button, and at the mains, nothing would bring it back to life.

I left the monitor switched off for several hours, then came back to it. On pressing the power button the LED came on and I heard the tube charge up, then merely a second later the LED went out and the tube discharged.

It seems as if the tube is charging up and trying to display as normal, but some protection circuit is cutting out the whole monitor before it can warm up. It can't be a blown fuse, as the monitor wouldn't have worked for even one second then.

Could the caps be dried out or vented? I haven't opened up the monitor yet, but I will do some time in the near future to have a look. In the meantime, anyone have suggestions as to what's causing this?

Note: The monitor does have a circuit that cuts off power to the tube when there is no signal or a DPMS off signal, but when that happens the LED blinks slowly. As it is now, the LED is not coming on at all, blinking or not.

[starfury1]

Re: Ibm 9525-002

well hopefully someone can narrow the field with a few likely suspects of whats liable to have failed component wise with this model.

all I can say from a block diagram level, is the most likely to fail is PSU or EHT
granted other problems could cause these to be shut down but Id start there.

I take it from what you say you have ruled out connector etc issues

and yeah caps are a good bet if its seen a reasonable service life...I take it, it was working when you stuck it in storage.

Sometimes resistors age and go high, components tend to fail more so in high current high voltage, heat stressed areas, chip, transistor failures are reasonably common too (more likely taken out then out right fail but that does happen! )

Do a good visual note the brand and type of caps in the psu and also look for dry joints,then I suppose the hard work begins.

Also let your nose guide you and possibly make sure there no arcing anywhere
it helps when checking this to power it up switch the light off and and see if you can see any blue trails
(there are from memory some spark gaps on the neck PCB)

You maybe lucky and there is a common failure problem with them, quick search reveal nothing much thought

As always BE CAREFUL, THERE ARE LETHAL VOLTAGES in that monitor

Anyway hopefully someone know the ducks to line up and knock down with it.

Good luck, Cheers