CRT Issue?

[blade002]

Hoping someone here knows what's causing this? I'm using a '19 IBM Trinitron CRT Monitor on my A1200 with an external scan doubler.

The issue is that intermittently the Monitor display does this weird thing where the screen for half a second shrinks about a half a centimeter and expands back to normal screen size.

So it kind of retracts a little bit and expands back immediately.

Any ideas?

[MoonDragn]

That sounds like a capacitor leaking somewhere. If it is a CRT monitor (tube) it means that your flyback voltage dropped below the required amount to activate the tube. That could indicate even more issues. Have you tried that computer on your tv or somewhere else to make sure it is not doing the same thing? Your monitor may be dying.

PS: Let me clarify... Often what goes wrong with CRT monitors/tvs is either the picture goes black, shrinks to a line, or goes to a dot. When it goes black, it usually is a fuse or a some other power issue or problem with the driver circuit to the tube. Line usually means a vertical section issue. When it goes to a dot, that means the driver circuits are no longer getting a signal or there is an issue with the driver circuit. So you have to verify that your signal is still good and not dropping out before you blame the CRT.

[jimbob]

Can you check if the monitor does this with a normal PC video source, just to eliminate the scandoubler.

I have a 17" Sony Trinitron which is great and works perfectly with PC but has a a bit of an issue when using an indiECS. Different problem from yours but still. . .

Always worth checking your cables and especially DB23 connectors are clean and solid.

[rjd324]

I have exactly the same problem with a Dell D1028LR. Currently in bits on the floor. Checked capacitors with ESR and they all seem to be fine so far. Will look for cracked joints and test capacitors on the neck-board.

Some people say that the build up of that sticky dust causes issues to.

Mine starts doing this after it has been on for a while.