Wei-Ya CH-2620S width reduction?

Jeff F

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Any idea which capacitor I should change to reduce the width? I've looked around here and arcadecontrols.com and couldn't come up with the specific capacitor.

Using this schematic...
http://www.vidiotarcade.com/tech/manuals/Wei-Ya_C2620HR_schematic.jpg

I'm thinking it will probably be C909 but I'm not sure... and I'm also not sure what size I should try?

Any help would be appreciated. :beerchug:
 
Did you set the Narrow-Wide jumper to Narrow?

This never works with the Weiya. It goes from "omg wow thats way too wide" when on the "W" setting. On the "N" setting its about 1 inch too wide on both sides, even with all of the width pots turned down. This is a repeating story from every 825 chassis story I've saw. I too have the same issue with my Weiya.
 
Yep, the jumper was already on narrow so I tried switching it for giggles and it did get wider.

After reading some more I'm pretty sure C908 is the capacitor I should be focusing on... can anyone verify that? I'll try messing with it this week.
 
Cool. Thanks for the confirmation. :beerchug:

I just stopped by the local electronics store on my lunch break and came out with a .47uF, .05uF, and 0.1uF(all 630v). Figure I'll swap in the .47uF first to see what that does. Then I can use the .05uF and 0.1uF to fine tune either the .47uF or the .39uF(if I have to put that one back).
 
Only reason I'll be a hero is I posted the information for this chassis on a public forum. :) I'm sure this has been done 1,000s of times before.

OR... maybe I could be a hero for the ginormous fireball I create when I fail!!! :D Maybe I should be videoing this...
 
Just wanted to say that I made some progress and I'm 99% sure C908 is the correct capacitor. I ran into a problem with the first chassis I received so I had to wait for my Alva shipment to arrive. Popped one of these chassis in tonight and I have a perfectly stable picture to play with now. :)

With the POS chassis I swapped out the .39uF with a .47uF and the picture was indeed reduced. But not enough. So with this new chassis I'll swap in the .47uF and then add the 0.05uF in parallel. Ran out of time tonight, hopefully I can play around with this over the weekend.
 
Ok, took a half day off work to play around. :)

-C908 *IS* the capacitor.
-C908 is 0.39uF(250v) from the factory.
-Changing C908 to a 0.47uF(250v or higher) Mylar cap gets you close.
-Adding a 0.05uF(250v or higher) Mylar cap in parallel to the 0.47uF capacitor on the backside of the PCB makes the width damn near perfect.

All these observations were with a Joust that was modified for negative sync(see here for simple mod).

I ended up just using the 0.47uF capacitor on it's own and then I minimized the width with the width coil(it's at absolute minimum right now).

If I ever take the chassis out again, I'll add the 0.05uF capacitor back to the bottom side so I can have some adjustment back in the width coil. I took the chassis out sooo many times I just didn't feel like doing it one last time.

From now on, I will swap in these capacitors as soon as I receive a Wei-Ya chassis. :)
 
Just wanted to bump this to add that I've done four more chassis/TV tube monitors since I posted this and I haven't needed to change the width capacitors in any of these four. :dunno:

I'm betting the horizontal coil in this original tube was a little outside the range of the Wei-Ya chassis... or this chassis just sucked butt. ;)
 
Just wanted to throw out a HUUUUGE thanks to Jeff F for this thread. Picked up my first Wei Ya chassis, an 826HR to replace a WG7401 in a Class of 81 Ms. Pac Galaga. Happy enough with the chassis, but that width adjustment was a killer... and if you can't see your score or the ship in Galaga it's not much fun. ;)

This post helped a tremendous amount. For me, I needed to put in a 0.1uf and a 0.047uf to get the screen to an acceptable width, and that's with all other adjustments on the chassis completed. Could probably put in another 0.1 to be honest.

It's threads like this that make the hobby so awesome - problem is documented for people like me to work through it. Thanks Jeff F!!

Daniel
 
Necro bump... I picked up a bootleg Dynamo cab that had a 'factory' Wei-Ya 826HR 27" monitor. I have a Arpicade running in it and it was just too wide.

I found this thread and changed out the 0.39 uF with a 0.47uF. This chassis had the 0.1uF cap in parallel @ C908A that is in circuit when the "Normal" width pin is used, but it also had another 0.1uF cap already in parallel w/ C908, for 0.59uF total. With the 0.47uF subbed in it was 0.67uF and was still too wide.

I experimented with the original 0.39uF and a 0.22uF (the only other cap I had rated above 400V) added. The 0.22uF was just at the edge of being able to show the entire screen. With the 0.39uF I was able dial the screen to show everything but there was a pincushion effect on one side that when adjusted out keystoned the other side, so I went with the 0.22uF. So in total this width section is @ 0.89uF for my monitor when the schematics have it @ 0.39uF (less than half).
 
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