Thought I'd make a post in case anyone else ever faces this problem and wants a fix. I had originally found the info that led me to the fix on another forum however I'm unable to find it at all now.
TL;DR
Replace R111 with a 0.68 ohm 1w Resistor
On my wei-ya I always had issues with playing cv-1000 games on groovymame, as they were always vertically to large to fit on my monitor. I just put it down to maybe something weird with the emulation resolution and never really took it too seriously. I did some research and found a post floating around, that I can no longer find, suggesting to replace r111 on the chassis with a 1ohm 1w resistor. So I bought one to have around and then promptly forgot about it lol.
Recently I had picked up a Deathsmiles pcb and it showed the same behaviour as it did using groovymame, unable to completely fit the image and losing about 5cm of the vertical image when at the minimum adjustment on both the v-size and sub v-size adjustment pots. Horizontal size was perfectly fine. This was annoying me and I remembered I had the resistor so I gave the mod a shot.
It worked a little to well, it was now way to small at the maximum adjustment. I now had a 'widescreen' CRT
:
At the very least the mod DID work and it was stable. I noticed no issues while leaving it on in the background for about 6 hours while I 'worked' from home.
I decided to look at some of the schematics of rebadged chassis to see what they used, as i only seen some old posts talking about this overscan issue for original weiyas in random threads. For the rodotron I saw that instead of 0.56 ohm they instead used 0.82 ohm. The makvision m3129d seemed to use 0.68 ohm. I ordered a 0.68 ohm 1w 350v resistor as it was closer to the original 0.56ohm.
It worked Perfectly
:
Sub v-size pot is now at 50% and remote board v-size pot is probably about 15-25% from minimum, giving me plenty of wiggle room for other 15khz and 31khz games. I've tested a bunch of other 15khz games, a Naomi, and a 2x6 and they are all able to fit fine after adjustments.
Open to feedback from any experts but so far this seems like a perfect fix.
TL;DR
Replace R111 with a 0.68 ohm 1w Resistor
On my wei-ya I always had issues with playing cv-1000 games on groovymame, as they were always vertically to large to fit on my monitor. I just put it down to maybe something weird with the emulation resolution and never really took it too seriously. I did some research and found a post floating around, that I can no longer find, suggesting to replace r111 on the chassis with a 1ohm 1w resistor. So I bought one to have around and then promptly forgot about it lol.
Recently I had picked up a Deathsmiles pcb and it showed the same behaviour as it did using groovymame, unable to completely fit the image and losing about 5cm of the vertical image when at the minimum adjustment on both the v-size and sub v-size adjustment pots. Horizontal size was perfectly fine. This was annoying me and I remembered I had the resistor so I gave the mod a shot.
It worked a little to well, it was now way to small at the maximum adjustment. I now had a 'widescreen' CRT
:At the very least the mod DID work and it was stable. I noticed no issues while leaving it on in the background for about 6 hours while I 'worked' from home.
I decided to look at some of the schematics of rebadged chassis to see what they used, as i only seen some old posts talking about this overscan issue for original weiyas in random threads. For the rodotron I saw that instead of 0.56 ohm they instead used 0.82 ohm. The makvision m3129d seemed to use 0.68 ohm. I ordered a 0.68 ohm 1w 350v resistor as it was closer to the original 0.56ohm.
It worked Perfectly
:Sub v-size pot is now at 50% and remote board v-size pot is probably about 15-25% from minimum, giving me plenty of wiggle room for other 15khz and 31khz games. I've tested a bunch of other 15khz games, a Naomi, and a 2x6 and they are all able to fit fine after adjustments.
Open to feedback from any experts but so far this seems like a perfect fix.
