VGA chassis with TV tube...

[bigh4th]

Ok.  I have a little test going on with a 27" rca television that got hit by lightning,  and a 17" CRT computer monitor with severe burn-in.

I've transplanted the yoke and chassis to the TV and after finally finding a schematic for the TV, found that I need to rotate the CRT socket on the neckboard one pin due to an indexing problem.    I carefully put the neckboard on without the index cap on the tube, and got a picture, albeit a bad one, due to need to adjust the yoke.  However, the picture is not full screen.

My question is this:  If after I get the convergence and colors adjusted properly, will there be anyway to adjust the picture to utilize the full screen, or am I stuck because I'm using a chassis designed for a 17" CRT?

And before it comes up, yes I am well aware of the danger of what I'm doing.  I know what and what-not to touch (capacitors, flyback, etc), and I am also not worried about any of the parts as they're pretty much scrap to begin with.

Thanks.

-Harry

[Pac-Fan]

You have multiple problems with this.

First, the flyback powering the anode is designed for the power required on a 17" tube. A 27" tube needs much more power to propel the electrons towards the screen at the great distance from the gun.

Second, the deflection angle between the two tubes is likely very different. I'm guessing the 17" is a 90 degree tube and the 27" is a 110 or higher degree tube (to compensate for the distance needed between the electron gun and outside edges on the front). Besides more power for the anode to suck the electrons forward, you also need more power for the yoke to bend the electrons towards the edges. Plus the yoke itself was meant to handle the angle of the smaller angle tube base on where the windings lie.

Besides simple safety issues as you pointed out when working with any monitor, doing such a hack is even more dangerous because you are forcing components to work outside of their norms. Granted you are likely underpowering the anode so xrays (out the front) should not be an issue, but these are things that shouldn't be messed with. Without proper deflection and power components mated with the correct physical devices you could be asking for many more problems than simply too small and too dim of a screen. (Read: Xray safety from the sides, fire hazzard on chassis components, etc..)

I'm no expert and will leave critial comments to them, but I definitely would never try such a thing myself.

[bigh4th]

I understand what you're saying and am in no way doubting you.  I just figured it would at least be an interesting test.

oddly enough, the chassis that came out of the TV was used for CRTs from 19-32" with the same components.  Thats why I figured this could possibly work.

The picture I got was bright like a normal monitor, just the colors were out of wack.

-Harry