Yoke Question

FrizzleFried

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I found a TV doner that was supposed to have the very same yoke on the tube as the one I broke (medium res). When I pulled the TV apart the yoke appears the same but is off by one number (the last number is -21 instead of -11). I also noted they used a tan/brown wire for the yoke in place of the green. So I put the monitor together thinking that if it didn't work I'd use the "-11" yoke I had handy.

The good news is I get a screen. It looks pretty good too. What I note:

(1) The image is stretched off the side of the screen by about 5-10%)... each side...

(2) The horizontal sync is on a HAIR trigger. If the screen goes too bright it loses sync...and won't go back...

(3) The vertical hold isn't working great. I can get it to hold... but again, when the screen goes bright, I lose sync and vhold...we're back to square one.

Can this be a yoke issue? I am doubting so as the image appears fine (aside from the stretching off the screen on each end)... I've not messed with the horizontal width as of yet..

The chassis has NOT been re-capped. I just want to make sure this isn't a yoke issue and then move on from there. I'm guessing a cap kit and replacement of the horizontal hold pot are the first order of business?
 
Were the inductance/resistance readings the same between yokes?

It's very possible that you may need to cap the monitor.
 
Were the inductance/resistance readings the same between yokes?

It's very possible that you may need to cap the monitor.

No idea frankly. What I did was that I googled the yoke number on the broken tube. I then determined that yoke was used on a specific model of TV (4 of them actually)... My broken tube had no markings other than TRINITRON so I knew it was a Sony. I assumed that if the yoke worked the tube should work so I looked for one of those 4 model TV's...

I found one a month or so ago and just got around to decasing it. What I found was a nice tube with the yoke that matched except the last 2 digits (-11 on the original yoke from the tube and -21 on the doner yoke/tube combo). The tube/yoke is perfectly converged so I don't want to yank off the yoke and drop the other one on that if I don't have to.

I don't have any idea how the monitor performed prior to the tube breaking... when I got the game the tube neck broke during transit so I never had the opportunity to see how well the chassis worked with the original tube/yoke.
 
The yoke just stretches the image to fit the screen. The problems you are describing sound like chassis problems.

Recap, check for cold solder joints, and report (helps with future searches). Also, if you can't reduce the picture size to fit the screen after the cap kit Bob Roberts has a write up on his page to adjust the horizontal width baseline by replacing a capacitor.
 
I was suspecting a chassis issue... or at the very least a pot issue (with the control board). I also found out the hard way that this monitor will NOT be a good replacement for my Golden Tee Complete / Silver Strike Bowling cab. It's an analog monitor, not a digital monitor... and each game has different syncs. If I get one looking good and I switch to the other, I'd have to manually adjust the sync every time. Not gunna happen. So this will just sit until I need it. So I'll likely not bother with the caps until I need the monitor. Why re-cap it just to sit (for what could be years)?
 
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