The Noise that killed my monitor....

[Hamselv]

Hi there,

I have had a generic arcade cab standing out in my garage for about half a year now, waiting for me to get time and energy to MAME the thing. The cab contains no game but is otherwise more or less intact, including the monitor, which is a 20-21" Philips 'Disco' type (I forget the exact model no.).

Anyway, once in a while I would fire it up, to see the monitor glow an enthralling white (no signal input yet). You know... just to see if the thing still worked.

The other day I did it again, and noticed that it would 'crackle' a bit, sounding a bit like the static noise you hear when touching a lit TV screen, only louder and ... slower. Not a constant crackle, but fairly erratic, if you can imagine that.

Well, I figured it just needed to warm up, so I kept it the monitor turned on for a few minutes. Then, all of a sudden, the noise went wild, going a bit like this:

zzrt - zrrt - zzzrrrrt - zzzrrZZZZRRRRRRTTTTT!!!!!! (how's that for phonetic description?). The noise ended abruptly, and the monitor is now dead.  I might add that my garage was fairly damp at the time, so it probably wasn't the cleverest place to keep a monitor without much cover  

Now, when I turn it on, the screen is blank, and I think that the very slight humming I can hear is just coming from the transformer.

Anyway, I have no idea what to check on this thing, to see if the damage can be repaired. Have any of you monitor gurus ever heard this kinda noise before, or do you have have any theories as to what might have gone wrong (where?). And of course, what are your suggestions with regards to repairing the thing, if possible?

I already have a 21" scart TV ready as replacement for my ArcadeVGA, but if the 'proper' monitor might possibly be fixable, then I will of course make the attempt.

Thanks in advance  

[DaveJ-UK]

I had this problem a while back.

It is indeed due to the damp. Someone told me it was condensation on the tube, which evaporated once the monitor had warmed up. So I stuck a little electric heater in it for a half hour before use. If it still crackled, I turned it off and left it another 10 mins with the heater.

I have no idea what will have blown though

[Ken Layton]

Damp garages kill more games every year.

The moisture has condensed around the rubber suction cup and the high voltage was arcing to the frame ground or the 'aquadag' tube coating. That arcing may have etched into the glass around the suction cup. Chances are now that your flyback transformer and/or horizontal output transistor are shot.

[mattv]

This sounds like somehting I should know more about.

Can this problem be avoided by making sure the back of the tube is dry before use? Or does the condensation build up on this inside of the tube too?

[Hamselv]

Thanks for the answers!

"Flyback and/or horizontal output transformer"....

Uhm... How would I go about testing these components (of course, without ending in a small, smoking pile of electrocuted ashes on my garage floor)?

[Ken Layton]

Flyback and horizontal output transistor testing are best left to experts.


Condensation can actually form under the rubber suction cup and leak into the hole (that's very bad). It's best to have a heated (and dry!) garage. Never let the temperature dip below 55 degrees (60 is prefered minimum). Moisture and high voltage make for an extremely dangerous situation which poses a grave safety and fire concern.

[Hamselv]

Ok, thanks Ken... I guess I'll get ready to dump in my TV instead.

But, are there any visible signs that could indicate beyond a doubt that the transformer(s) are dead? And are there any other possible (and non-lethal) things I might check first?

[Ken Layton]

Sight and smell. Clean off the flyback very carefully with spray cleaner on a rag. Look closely for cracks and/or pinholes in the flybacks case. Sniff for a burnt smell.