Vectrex with problem need advice
- Thread starter vsl
- Start date
Hi everyone,
After replacing all the electrolytic capacitors and the five DAC capacitors in my Vectrex, I’m still not happy with the display.
All voltages are stable and within the specifications in the service manual. I’ve carried out all the adjustments I could, including setting the NE555 timing to 10 ms / 40 ms using an oscilloscope.
However, the test grid still jitters quite badly. Every now and then, the whole image briefly expands, almost as if it’s “zooming in.” Unfortunately, this doesn’t show up in the video. Some of the text also looks distorted, which you can see in the video.
I suspect that something other than the capacitors may be causing these problems, but I’m running out of ideas about where to look next.
Has anyone experienced similar symptoms, or could you suggest what I should check next?
Thanks in advance!
After replacing all the electrolytic capacitors and the five DAC capacitors in my Vectrex, I’m still not happy with the display.
All voltages are stable and within the specifications in the service manual. I’ve carried out all the adjustments I could, including setting the NE555 timing to 10 ms / 40 ms using an oscilloscope.
However, the test grid still jitters quite badly. Every now and then, the whole image briefly expands, almost as if it’s “zooming in.” Unfortunately, this doesn’t show up in the video. Some of the text also looks distorted, which you can see in the video.
I suspect that something other than the capacitors may be causing these problems, but I’m running out of ideas about where to look next.
Has anyone experienced similar symptoms, or could you suggest what I should check next?
Thanks in advance!
That mostly looks good to me. The Vectrex is never perfect and screen wobble when displaying a lot of vectors, and imperfect alignment is normal.
However, you shouldn't have sound continuing to play when leaving the sound test. I notice the ROM checksum is for the "no-buzz" version of the Vectrex. I thought yours is a regularly buzzing Vectrex? Having the wrong ROM installed could cause issues.
However, you shouldn't have sound continuing to play when leaving the sound test. I notice the ROM checksum is for the "no-buzz" version of the Vectrex. I thought yours is a regularly buzzing Vectrex? Having the wrong ROM installed could cause issues.
Thanks for your reply! I just want my Vectrex to be perfect. 
The console was bought in the USA and originally ran on 120 V. I replaced the original transformer with a toroidal one with the appropriate specifications: 230 V, 50 Hz primary, and a 9–0–9 V centre-tapped secondary, rated at 50 W. I’ve even moved it outside the console to keep electromagnetic interference away from the circuitry.
Which ROM would you recommend, and where can I download it, so I can rule that out as a possible culprit too?
The console was bought in the USA and originally ran on 120 V. I replaced the original transformer with a toroidal one with the appropriate specifications: 230 V, 50 Hz primary, and a 9–0–9 V centre-tapped secondary, rated at 50 W. I’ve even moved it outside the console to keep electromagnetic interference away from the circuitry.
Which ROM would you recommend, and where can I download it, so I can rule that out as a possible culprit too?
Retro Marky
Newbie
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- 43CR
I think (it's been a while!) there are pots on the main pcb and the daughter board totalling 4?
I also remember having to undo the yoke on mine and fine tuning the image by physically moving it (careful of the voltages in there as well!)
I also remember having to undo the yoke on mine and fine tuning the image by physically moving it (careful of the voltages in there as well!)
That looks like the regular "buzzing" Vectrex board, so you have the wrong ROM installed, I think.
The ROM won't be the cause of the screen zooming issue, though. That sounds like an issue with the deflection board or possibly the neck board. A dry joint, maybe?
Have you ever removed the large black heatsink for any reason? Does it get really hot?
The ROM won't be the cause of the screen zooming issue, though. That sounds like an issue with the deflection board or possibly the neck board. A dry joint, maybe?
Have you ever removed the large black heatsink for any reason? Does it get really hot?
Did you solder the LM379 in before fitting the heatsink? I made this mistake once. The correct way is to securely fit the LM379 to the heatsink first, before fitting and soldering.
If done wrong, the heatsink on the LM379 doesn't make contact with the large heatsink, causing it to overheat. This can cause odd vector faults.
backflipper
Active member
So what was causing the problem?
Thank you big10p and Georgian2 !!!
Your help has been amazing and really helped me pinpoint the problem. There are still some imperfections in the picture that I need to work on. I may ask for your advice again if I can’t manage to fix them.Тhis is my first experience working with a vector display system, and I’m finding it very interesting!