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Wells Gardner D9200 - Horizontal Collapse?

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Hi everyone! First time poster here.

I've recently acquired a Big Buck Hunter II: Sportsman's Paradise and it has seen some action. The guy I got it from said the machine would turn on, but the monitor wouldn't work and crackles, pops, and sparks would shoot out of the back. After a lot of research I learned I have a dreaded 27" Wells Gardner D9200 monitor. This is where the rabbit hole of woe and sorrow started. Apologies in advance for the long post.

I began by fixing some broken ground wire connections and fixing some solder joints. After that, the monitor would work, but still made crackling sounds every now and then, and the picture jittery at times. The common fix for these issues is to replace caps, so I replaced all 76 of the electrolytic capacitors (and made a list of every single cap if anyone wants it). That smartened up most of the issues. I could then see the monitor has some burn-in (not much I can do about that) and the image was rotated slightly counterclockwise. I adjusted VR101 to rotate the image, but it was already cranked as far as it would go so nothing could be gained there. I foolishly thought "I've manually fixed a rotation problem like this on a TV before, I'll just do that here". I didn't know at the time that the yoke is adhesive bonded to the tube's neck.

I could see there was hot glue all over the yoke, so I used a soldering iron to melt it away. I managed to get it to the point where I could wiggle the yoke, and I could twist it about 1 or 2 degrees, but it still offered resistance. This was enough to get the image straight though, so I just taped it in place temporarily while I adjusted other settings like color and gain, etc. I really wanted to get the colors better than they were, so I was attempted to hook up a laptop using a VGA cable so that I could run a CRT test pattern, but that darn chassis board would not play nice with my laptop. It might have been a resolution setting in the laptop, or it's something on the chassis board. I eventually gave up and put all the connections back to stock.

Shortly after this I wanted to see if I could copy the contents of the hard drive onto a CF card to use that for a boot drive because the original hard drive did not sound happy and I anticipated that any day now it would pack it in. That process is a whole nother story, but during the attempts to use the card is when the D9200 suddenly started making a horrible high screeching frequency noise and the image started experiencing what I think is horizontal collapse. When the machine boots up the text is all wobbly / jittery / zig-zaggy (see photo), but when the game is finally loaded, it actually looks like it's displaying "fine" but is just squished into 2" wide (see photo).

Here's the things I've checked so far:

Q412 - checks out fine
Q413 - checks out fine
Q414 - checks out fine
Q415 - checks out fine
Q425 - checks out fine
Q426 - checks out fine
Q427 - matches Q426
Q428 - had to remove it from the board, but checks out fine

D417 - checks out fine
D423 - checks out fine
D424 - checks out fine
D426 - checks out fine

VR402 - is good
VR101 - not good! Supposed to be 10k ohms but only got up to 4k. Likely the cause of my crooked image in the first place. I'll be replacing this one.

R312 - good
R314A, R314B - each read 0.4 ohms, but I didn't remove them from the board, but if I did I think they would read the expected 1.3 ohms
R318 - good
R415 - good
R418 - good
R424 - good...I think. It takes a while, but it eventually climbs up to 15k ohms.
R462 - good
R480, R479, R78 - each read 0.3 ohms, but I didn't remove them from the board, but if I did I think they would read the expected 1.5 ohms
R853 - good
R854 - good
R855 - good

Things I know I should check but haven't:
IC 404
IC 403
I don't have a way to test them powered up. The monitor is still in the cabinet and I have the chassis board on the workbench.

Some of those parts I de-soldered from the board to measure them individually, but some of them I tested still in the board. The only ones I removed were ones that were throwing out suspicious numbers. If it was close to the stated resistance value found on the schematics, I left it on the board to check.

I've done a lot of internet browsing for possible answers and spent a couple weekends attempting to fix this, but I'm still at a loss, so any insights you have would be greatly appreciated. Or should I just yeet this thing into the sun and find a 27" TV with S-video input and use that instead?

do you get full deflection with video signal disconnected?

Good question! I have not attempted to turn it on with no signal connected. If it displays the boot text normally with no signal, that would mean there's something wrong with the IC that does the resolution switching, yes?

the max res on these is svga, some of these chassis revisions only go vga as the components are not on the chassis - i wonder if you went past the max res and damaged something, i doubt it would be ic, maybe a fet or transistor but looks like you checked most of them. q418 checks ok?
see what happens with no signal

It seems like it should be a transistor to me too. I did take out Q418 and checked for resistance between pins, and it did give results. I have read other posts where these components were fine out of the board, but when they were on the board and powered up, they would start to overheat and mess up the values, thus not work properly. Maybe that's what's happening?

I should probably explain how I'm testing the parts. I'm not electronics expert, so I've just been googling these things.

For Mosfets I was putting the multimeter in diode mode, then measuring the center terminal to each outer terminal. I should see around 0.5V on one leg and nothing on the other.
I could also measure their resistance between outside terminals and get around 1.2 ohms.
I could also measure for continuity between the outside terminal. There should be none.

For Transistors, I'd use diode mode on the meter, measuring between the center leg and either outside leg. They should read around 0.6V

And because I'm not sure if any of that is correct, if I had the component off the board I tossed it in my transistor tester. It's a common gizmo that tests much more than just transistors (see pic).


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