Nanao MS9 to Wei Ya 3129A Chassis Swap Guide

[mirkvid]

Edit: Here's what the picture looks like. I'm confident I've got the chassis wired up correctly, however there may be a grounding issue. I've tried both the NAC power cupply and the 3-prong power cable that came with the chassis.

[grantspain]

the focus is only affected by the flyback or the tube,do you have three pots on the flyback or two
some of these chassis use a dual focus flyback with one of the focus wires tied back

can you post a photo of the flyback

[mirkvid]

Here you go:

back of the flyback:



top - some green wires that aren't connected to the neckboard.:



where the green wires connect to the chassis.




The manual states that there are 3 other focus pots on the chassis, one for 15k, 24k, and 31k but reads that they are set from the factory and not to adjust them. I turned the 15k pot and it didnt help. all my games are older jamma titles. i don't have this hooked up to a pc or anything.

Thanks again!

[grantspain]

those 3 pots you mention are the b+,you should not touch them

unless your sub contrast is super high then i think your tube has had it

[mirkvid]

I'll check the sub contrast. I just pulled a sanwa chassis out of this and the tube was fine. Ill install the sanwa this weekend and check again .

[mirkvid]

Unfortunately it looks like my tube is bad. I installed another chassis and got the same result. Time to start hunting for a replacement.

Thanks again for your help, ill post some pictures of my cabs once i get this one sorted.

[Steur]

Hello,
sorry to bump this thread,
do you think it could work on a ms8 25 toshiba tube ?
Apparently the 3129A works also on ms8. My Madonna got an ms8 chassis from an astro city.
So it should work, isn't it ?

[nem]

Don't get a Wei-Ya. It's a terrible chassis that will inevitably fail.

MS8-25 and MS8-29 are more or less the same value. You could sell your MS8-29 and get a MS8-25 with that money. The Madonna has a MS8-25FAR originally, but you can replace it with any MS8-25. There's an US seller on eBay that has a ton of MS8-25 currently for sale. They're all untested, so most likely have issues. But it's not a hard chassis to fix. Send it to someone like Grant and he will fix it in an afternoon. I fixed half a dozen of these just by reflowing solder joints and putting new caps in.

[Steur]

Thank you for your answer
I just wanted to test 31khz on a Madonna but a dedicated candy cab should be better.

[nem]

I know what you mean. I regularly look at my Madonnas and wonder how awesome 31khz games would look on the 25" Tosh. However, I don't think there's any good way of achieving it.