Vectrex monitor: minor upward curl at left & right sides

[jasonbar]

What think you of these 2 attached images?

There is a slight curl-up on the sides of the image.

I believe that this is normal & within tolerance. I.e., with a 9" non-flat CRT screen, this level of distortion is expected.

I've looked through the service & troubleshooting manuals at www.playvectrex.com/shoptalk_f.htm & can't see any corresponding entries that address how to clean this up.

Any input? Any comparisons to your own Vectrex screens?

Thanks,
-Jason

Attachments:

[gliptitude]

I don't notice anything askew really. The image looks reasonably centered, which is the most common manner of divergence that I've seen on my various Vectrex's. I have had I think 7 "working" Vectrex's come through my hands and most of them were at least slightly off center. One that I still have is BADLY off center, so that the bottom third of the game graphics are cropped.

I don't have the service manual handy, but there are a few pages of spreadsheet like information in it, with symptoms in one column, possible diagnosis(s) in another column and possible remedies in another column. ... Most remedies entail use of the TEST CART to make observations.

I know that off center display and some similar problems were listed in that "spreadsheet".

[jasonbar]

Thanks, gliptitude. I'm aware of the centering adjustment pot & the X & Y adjustment pots. I've used the service/troubleshooting manuals many times to address image problems. Those tables don't refer to a curl-up on both sides of an image--they refer to the usual problems: white center dot, vector wiggling, skewed text, etc.

I'm just trying to get opinions on if those images look normal, and, if they don't, what might be done about it.

Thanks,
-Jason

[gliptitude]

The images look normal to me. Like you say, the screen is not flat.

[VectorX]

They're not quite normal; I see the "curl" jasonbar's talking about.

[kokovec]

I just finished up a cap kit on my Vectrex and had to make quite a few adjustments (some with a scope).
Try to run the test cartridge rom. There are a couple of tests that will tell you if something is off with the screen adjustments.

[jasonbar]

Thanks. I've already gone through the test cartridge & adjusted the 3 pots (center, X, & Y), & I think that the image is fine. My opinion is that, because of the screen curvature, depending on the angle of viewing, straight lines can appear to be slightly curved.

Here are 3 pics from another Vectrex. It was sitting on the floor when I took the pics, so my viewing angle is higher than the center of the screen. I see a general leftward bowing & a little upwards bowing, but the severity of the bowing seems different in different images, most likely due to a slightly different camera angle between shots.

Thanks,
-Jason

Attachments:

[kokovec]

Also, if you follow the procedure in the manual centering the screen is done via the centering magnets on the back of the yolk (and not the pots).

[jasonbar]

Thanks--I always shy away from adjusting yoke magnets--getting into that portion of a monitor is slightly scary--I generally worry about making things worse by getting into yokes--they're a bit of black magic to me. :]

Thanks,
-Jason

[jasonbar]

Howdy-

I got another Vectrex in stock & its image's left side is bowing in somewhat noticeably--more so than can be attributed to small old CRT curvature.

On this machine, I did go ahead & loosen both clamps on the yoke, per the troubleshooting manual. I pushed the rings towards the front of the tube. They were already seated & didn't budge.

I rotated both "back" rings gently (the ones loosened by the "key" screw)--they simply translated the image around the screen, which can aid in centering beyond what the PCB back pot can achieve. They didn't change any distortion, as best as I could tell.

I then tinkered with the front rings (the ones loosened by a Philips head screw)--they didn't change keystoning/pincushioning/bowing either--they just rotated the entire image.

Thanks,
-Jason

[kokovec]

Looks like there's a cap kit in your future.
I changed out all my caps and the power transistor.
I needed a scope to readjust the high voltage as the image was distorting at about 3/4 the size of the screen.
The flyback transformer might be dying as well. I hear a high pitched squeal while turning on or off the Vectrex. I don't think I can find a replacement and I'm debating if I should try to reverse Engineer it.

[jasonbar]

Thanks--the first time I put a Zanen cap kit in a Vectrex, I killed it. That was also the last time that I put a Zanen cap kit in a Vectrex...

-Jason

PS--not blaming Zanen--surely operator error!