Help: new Wei Ya 825H1 chassis and picture is too wide

[Toonces]

I just replaced the chassis on my 25" unknown monitor (unknown Kortek Chassis. No numbers) with a Wei Ya 825H1 and the picture looks great but is too wide. The Horiz adjustment pot is all the way down and the jumper near the back of the chassis next to the flyback is on the N pin (I assume that is the Narrow pin as the other is labeled W (Wide?)). There is another jumper type pin near the Horiz Width Coil that has V & W pins but since I don't know what that does I didn't want to mess with it. The Horiz Widt Coil does not appear to be adjustable at all as the slug is solid and does not rotate down in any manner that I can see.  It's enough too wide to be pretty noticable, cutting off a big slice on both sides of a game. Other than that, the chassis seems to be very nice with pincusion adjustemnts and all.

Ken or anyone, any ideas???

Thanks!

Toonces

[Ken Layton]

Have you used your plastic TV Alignment tool to adjust the width coil?

[Toonces]

That's the problem, the width coil doesn't have a way to do that. The center slug is solid with no hole to use any adjustment tools. It also looks like it's glued in place.

Thanks!

Toonces

[Ken Layton]

I don't have schematics to those chassis. Perhaps an email to the seller will give you a capacitor location to change the value of to reduce picture width?

[Toonces]

Thanks Ken, I'll send an email to Alva and see if they can help. Hopefully the language barrier won't be too great They were easy to order from if you know what you want.

Best Regards,

Erik

[AlanS17]

Even if you had a wya to turn it, trying to turn it while it's glued would likely break it. Still if it's glued that means it's got to be holding it in place for some reason. That means you should be able to turn it, even if it's not readilly evident. If Ken's idea falls through, try finding a way to get that glue off. Maybe then it'll be easier to find a way to turn it. Is it hot glue or something firmer?

[Toonces]

It looks like either a black epoxy or some sort of black stuff with a clear gloss glue over it. kind of difficult to tell. I tried to scrape some away but it seems pretty solid and all I did was make some scratches in it. I was thinking, the adjustment for Horiz Size on the chasis (other than the width coil) is a 3 legged trimmer pot. Looks the same as all of the adjustment pots for everything else. What about removing that pot and replacing it with one of a higher value? I beleive that increasing the resistance is narrowing the width. I'm not sure what the value is until I remove it but I am thinking that putting a larger value pot withh give me enough to get it down within the monitor edges. Or is that a bad idea?

[AlanS17]

I'm not sure what the value is until I remove it but I am thinking that putting a larger value pot withh give me enough to get it down within the monitor edges. Or is that a bad idea?

I'm not knowledgable enough on the topic to give a definite answer. In theory, it sounds like a decent idea. I'll let the real experts weigh in, though.

[Toonces]

UNless I get some other info today I think I'll give it a try. Hopefully that won't turn out to be a bad thing

[Toonces]

Ok, I tried replacing the 5K pot with a 10K and it made only a very minor difference. I am beggining to wonder if I should have gotten the 826H chassis instead. Hopefully I will get an answer from them soon.

[wakerlet]

The problem is that everyone is trying to use these things with the yokes that came from other chassis.

I bet if you order the specific yoke from them that matches the chassis, there will not be a size issue.

[Ken Layton]

The problem is that everyone is trying to use these things with the yokes that came from other chassis.

I bet if you order the specific yoke from them that matches the chassis, there will not be a size issue.

[AndyWarne]

This is the kind of issue I have just been looking at.
Reason is: I have found a source of monitors which are the most fantastic monitors I have ever seen. They have OSD with memory, will handle 15, 25, 31, 38 Khz and have every OSD control possible, including rotation, all of which work. The holy grail of monitors. I am thinking about the practicalities of selling the chassis assemblies without CRT, as we don't have the space for CRTs and I certainly don't want to get into sending them around the world!
The problem is, this yoke compatibility issue is likely to rear its head with this plan.
I am wondering how many different yoke specs there are and is there any way of identifying the spec of the yoke?
I don't think swapping yokes on the CRT is a good idea as the convergence and purity would never be right.
I am going to look into this issue but any feedback welcome (Ken?)
Andy W

[AceTKK]

This is the kind of issue I have just been looking at.
Reason is: I have found a source of monitors which are the most fantastic monitors I have ever seen. They have OSD with memory, will handle 15, 25, 31, 38 Khz and have every OSD control possible, including rotation, all of which work. The holy grail of monitors. I am thinking about the practicalities of selling the chassis assemblies without CRT, as we don't have the space for CRTs and I certainly don't want to get into sending them around the world!
The problem is, this yoke compatibility issue is likely to rear its head with this plan.
I am wondering how many different yoke specs there are and is there any way of identifying the spec of the yoke?
I don't think swapping yokes on the CRT is a good idea as the convergence and purity would never be right.
I am going to look into this issue but any feedback welcome (Ken?)
Andy W

Where are people going to get the tubes?  Would a standard television/CGA mon. tube work with these, even though the chassis supports VGA resolutions?  Is the dot-pitch (is that the right term?) the same between a t.v. tube and a large VGA monitor?  RE: the yokes, I think you would have to do some testing to determine what range of horizontal and vertical resistance values would provide acceptable results.  If the pin-cushion and size controls are robust enough I would think that some degree of variation in the yokes could be compensated for. 

-Ace-

P.S. I have a 27" tube just waiting for a donor chassis; if you need a test subject I'd be happy to volunteer 

[Ken Layton]

I just saw a picture of the 826 chassis. The width coil is white. Is this the coil you are attempting to adjust?

Wells-Gardner likes to glue the width coil slug in place with their monitors. I hope Wei-ya has not taken to this practice also. A method to loosen/soften the glue is to blow the hot air from a hair dryer on the coil for a little while. Usually this will soften the glue enough to allow you to adjust it before it cools down and hardens again.

[Toonces]

I just saw a picture of the 826 chassis. The width coil is white. Is this the coil you are attempting to adjust?

Wells-Gardner likes to glue the width coil slug in place with their monitors. I hope Wei-ya has not taken to this practice also. A method to loosen/soften the glue is to blow the hot air from a hair dryer on the coil for a little while. Usually this will soften the glue enough to allow you to adjust it before it cools down and hardens again.

Yes, the slug appears to be solid though. I will give the hair dryer thing a try as it looks like there is glue over it as well. I figure if I can get it up some I should be able to get it narrow enough. I will post some pictures of the 825H chassis today. I would think the 826 is pretty similar.

Thanks,

Erik

[Toonces]

Here are picutres of the chassis.










And 1 of the screen. You can see that half of the M and the L are cut off.

[Ken Layton]

Yeh that white coil is the width coil master adjustment. This chassis does indeed need an isolation transformer.

Oh, looky this----what is this I see? Why it's a pincushion adjustment. 

Sometimes some manufacturers put a hole in the circuit board directly under the width coil so you can stick the adjustment tool into it in case you can't do it from the top of the board. If this chassis doesn't have that feature you can either use the hair dryer method to soften the glue on the coil or buy a replacement width coil for that model. Generally replacement coils do not come glued in place.

[Toonces]

Just got the following response from Alva:

To make it narrow you should change the cap C912  222K(2200 pf = 0.0022) , 2 Kvolts, you should change for a smaller capacity maybe 182K

So I may give that a try if I have one around or can get one locally. I also may try the hair dryer and even thought of removing the width coil and seeing if I can adjust it from the bottom.

[Toonces]

Ok, I pulled the chassis and did a little investigating tonight

first I returned the original 5K pot to the H width (I had replaced it with a 10K pot which proved to make very little difference).

Next I looked at C912 as Alva had instructed. It is the smaller chicklet style cap next to the flyback. After looking at where the cap was I think what they told me would only be valid if the Narrow/Wide jumper is in the Wide position.  In the Narrow position, C912 appears to be taken out of the circuit and in the wide it appears that C912 is placed in Parallel with C902. Since I already have the jumper in the Narrow position, C912 appears not to be used. I forgot to write down the value of C902 but if I recall correctly it is 1333K 13330pf .01333 (?) Anyways, it would appear that if I want to have an effect on the width by replacing a cap, it appears that C902 is the one to replace as it is always in the circuit.


Next I removed the width coil. The slug is solid on both sides and is as long as the coils windings. I proceeded to push the slug out from the bottom so it was sticking out of the top and gave me something to grab onto in order to adjust it. It is not meant to turn but rather just slide up and down. I replaced the width coil and installed the chassis. On powering it on I was greeted with a narrower screen but still not quite enough. I turned off the monitor and adjusted the slug up pulling it more out of the coil. Doing this several times showed me that there was a sweet spot for the slug before it started getting wide again. I thought it was strange since I was pulling it out that it would start widening again. I thought that if it was removed completely that it would be at it's narrowest. I never removed it all the way but had quite a bit sticking up the top.

So where I am at now is that it's almost there. In the screenshot below, if you look at the bottom you can now see Edit 00 on the left and Credit 0 on the right. Tomorrow I plan on getting the numbers off of C902 and getting a smaller cap. Any suggestions on how much smaller? 10%, 20%??

Thanks for reading through this and for any help or suggestions you can give. I am hoping by going through all this it will help others with the same chassis be able to be able to get around width problems.

Toonces

[castlesteve]

Bump..

So Toones, did you have to change C902 to end up fixing your width problem?

-s