Monitor question

[maelstrm]

Good day, Federation,

There's a monitor I'm interested in, and there's several photos of it available. But in each photo, the image on the CRT is exactly what is shown below, even from different angles. So this doesn't appear to be a shutter speed thing on the camera. Assuming it's not receiving a signal, does this indicate a fault? It has composite in as opposed to MDA. I have a few monochrome monitors. When there's no signal coming in, all of them show either a full screen fully lit, or no image at all.

Any advice would be appreciated. Thanks!

 

[daver2]

I would say that this does indicate a fault of some type. The brightness control could well be turned right up, but that should not still give you that kind of image on the screen.

Dave

 

[maelstrm]

Thanks, Dave. That's what I kinda suspected. I guess a partial horizontal collapse. But just guessing.

 

[daver2]

There is a vertical issue not a horizontal issue...

Dave

 

[MicroCoreLabs]

Is there a potentiometer to adjust the vertical position?

 

[maelstrm]

Is there a potentiometer to adjust the vertical position?

There's the regular V-Sync and H-Sync on the back. Not sure if there's any adjustments inside.

 

[MicroCoreLabs]

Does display respond at all to changing v-sync?

 

[maelstrm]

I don't have it. It's on that's for sale.

 

[daver2]

Unless the seller can demonstrate it works, I would stay clear of it (unless you are happy to repair a potentially faulty monitor, or can negotiate the price so that you can afford to treat it as potential junk if it doesn't work).

Dave

 

[1ST1]

There are monitors which do things like that if the video connector is "open". What we also can see is that high voltage is ok, x and y is ok.

 

[MiaM]

That is a super common monitor. Schematics:
https://archive.org/details/manual_BM7502_PHILIPS/mode/2up

It uses discrete transistors for all of the vertical deflection circuit, and should thus be relatively easy and cheap to repair.
On the other hand it's not a particularly valuable monitor even in working condition so don't pay much for it.

 

[MicroCoreLabs]

How much are they asking?

 

[nickb333]

That is a super common monitor. Schematics:
https://archive.org/details/manual_BM7502_PHILIPS/mode/2up

It uses discrete transistors for all of the vertical deflection circuit, and should thus be relatively easy and cheap to repair.
On the other hand it's not a particularly valuable monitor even in working condition so don't pay much for it.

Those monitors date back to the late 1980s and were available with green, amber or white CRTs. Usually a good quality picture but the creaky plastic might put you off.

 

[MiaM]

Addendum:
I assume that they use the same power switches as the color monitors with similar designs (Commodore 1080p and the Philips CM88xx series). Those are known to go bad where the button won't stay in the on position. I recommend that you leave it in the on position and use a power strip or whatnot to turn it on/off.