How to adjust width on Wei Ya 825H Chassis

[Toonces]

I started a discussion in another thread when I received my replacement chassis from Alva Amusement (http://www.alvaamusement.com). In short, my Neo Geo 25" had some sort of Kortek monitor that would blow fuses. Not being able to find schematics, I didn't know where to start troubleshooting so I bought a replacement chassis from Alva. My tube is low impedance so I got the 825H. It's a nice chassis with full controls including pincushion. The cost of the chassis was $69 + shipping and came to a total of $76. Much cheaper than 8liners and video1963 on eBay and it's the same chassis (video1963 sells the 826HR that he gets from Alva. The 826HR has remote board for adjustments and the cost is the same as the 825H. Wish I had known that when ordering.). Anyways, When I hooked the chassis up, the picture came up and was beautiful, albeit too wide. The H width controls did very little to change that. The H Width coil uses a solid slug and is not really adjustable without removing it.

My first attempt to get more width adjustment was to replace the 5k H width pot with a 10K donor from another chassis. Not much difference at all. I put the original 5K pot back and looked for a way to adjust the width coil. I also emailed Alva and explained my problem.

My first response from Alva was to use the H width pot. I replied and told them that I had already done that.

In the meantime I started on figuring out how to adjust the width coil. I removed the coil and examined it closely. It is solid and glued in place. I also noticed that it is not meant to be turned as the inside of the tube has vertical ridges. Using a small screwdriver I gently pushed from the bottom and was able to get the slug to move up. I pushed it up far enough that I could grab the top of the slug (with the monitor OFF) and pull up more with a pair of pliers. After replacing the chassis and making several attempts at adjusting the width coil I was closer but the picture was still too wide. On the bottom of the neo geo screen it shows credit 00 for each player. On the left it now said edit 00 and the right said credit. I was getting closer but not enough.

After I had done that, I got another reply from Alva:

Erik:
To make it narrow you should change the cap C912

[AceTKK]

Glad you got it sorted out!  Thanks for the nice write up.

-Ace-