Vectrex alignment issues help

[ruckage]

Hello. I'm new user here but wondered if anyone could offer some advice.

 

I recently bought Vectrex which is generally in very good condition and works well except for some alignment issues that are more obvious on certain games.

I saw some guides and have used the test cart to correct what I can. The DAC adjustment is set to 0 and I've used the 2 vector adjustment pots to make sure the Integrator offset screen looks as perfect as I can get it but things still don't seem to align quite how they should.

 

The issues show up mainly in games with rotating objects such as the player ships in games like Ripoff. The ship seems to distort and lines cross over one another as the ship rotates.

There is a link to short video below to try and show the problem - notice the wings that should be separated come together and then pull apart again as the ship rotates:

 

https://i.imgur.com/SxMf0Dh.mp4

 

I can use the pots to correct for this and the ship will rotate normally but then other games and the integrator test screen show poor alignment (for example the ships in Starship are drawn with a large gap in them where the lines no longer join up).

 

Below are photos of screens from the test cart. Do you think this problem is due to the Caps needing to be replaced or does it point to another problem? Thanks in advance for any help.

 

 

 

 

 

 

[mattsoft]

When you say DAC adjustment is set to 0, I presume you mean you checked voltage from pin 1 of IC304 while the screen blanked?

 

Also, if you haven't replaced the styrene caps, I would start there. It seems that is a good place to start from when troubleshooting screen issues.

 

Overall though, it doesn't look bad.

[ruckage]

Thanks for the reply mattsoft.

 

Yes the DAC was adjusted exactly as you say while the screen was blank (I waited and only made adjustments while the message 'DAC adjust' wasn't displayed on screen). In the end I think it was 0.002 volts - I couldn't get it any lower than that but I assumed that would be close enough.

 

I didn't think the test screens seemed too bad either but obviously something isn't quite right as the sprites (is that the correct term on a vector display?) shouldn't distort as they currently do. There is also some wobble on the lines on the test cart and I've also noticed on some games the screen seems to shrink and expand slightly depending on what's displayed. Without having a perfectly working unit to compare to it's difficult to know if this is normal behaviour. Text and some other graphics also seem to lean to the right, particularly obvious on the homebrew vectris game from the 'all good things' collection.

 

A cap replacement is something I was planning for so will probably change all the caps at the same time, hopefully that will fix it.

 

Thanks again for your help.

[mattsoft]

I'm by far from an expert, actually quite novice, but it seems that the Vectrex is a fickle beast. Mine had all sorts of display issues until I recapped it. It's pretty good now, but the vectors all "wobble" all the time. The more vectors, the more wobble. Maybe it's normal -- it's hard to tell. Never had one as a kid! I see videos on YouTube of working Vectrexes (Vectri?) and they all seem to have vector wobble; some being worse than others. From your pics and video, your display is not too bad. if you get it recapped, come back and let us know if it helps! Start with the styrene caps -- they are EASY to replace and the most common source for display issues.

[SnakeGrunger]

We seem to have the same problem. I posted another topic and my problem seems a bit worse than yours - but difference is I have done a complete and full recap.