19" Wells-Gardner k7000 issue

[shawnbo42]

Ok, I like to think I am halfway decent with repair of the beasts, but I recently ran into a problem I have never seen before, and I am wondering if maybe anyone here has any idea about this.

I've got a Lethal Enforcers conversion, 19" monitor, tube was a Wells 7302. Unfortunately, said 7302 is only 2 years old, but parts are no longer available, so it's basically junk. Yanked that tube out, and dropped in a k7000 out of a Joust that's been working fine for the last 3 years without so much as a blown cap.

Stick the 7000 into the Lethal Enforcers, and fire it up. No picture. I DO have high voltage, neck glow, all the usual. As a matter of fact, with the screen controls (black level, contrast) cranked all the way, you can see the border of the picture around the edge of the tube. But, no actual image. Now, the really weird part.

When I power OFF the machine, AS THE MONITOR POWERS DOWN, *poof*, there's the image. For about a half a second. Likewise, when you power ON the game, you get the image. For about half a second. In order to see this, you have to flip the game off and back on rather quickly, but it is most definitely there.

Now I thought this could be due to my sync wire in the wrong place, but on a k7000, IIRC, even with the sync wire removed, you'll still get an image, it'll just be scrambled.

So, to sum up.
Have High Voltage
Actually can SEE the screen borders
All 5 input wires are present
I can see a picture when I power on or off the machine, but it disappears very quickly
Monitor was known to be good upon removal from the previous cabinet.

Basically, I have no idea. Anyone else want to take a crack at it?

[XYXZYZ]

Are you sure the chassis and tube are compatible?

[shawnbo42]

Chassis and tube were removed together from a working game prior to the install in the Lethal Enforcers, and working fine.

[shawnbo42]

Thanks, I didn't consider the iso. I assumed that since it was ok with the previous 2 tubes, it would be ok for this one as well. It's worth a shot anyways. I suppose it's possible that my wall voltage is too high, but the monitor would go into shutdown if that was the case, I believe. Even though I can't see the actual image, I can see the borders of the screen (with my brightness controls turned up), so I am not getting an actual monitor shutdown, which is why I can't figure it. But I'll give both your suggestions a shot, and see where that gets me. Hopefully, a working game :)
Thanks again.

[Peale]

I doubt it's the iso xformer. I'd say it's some kind of incompatibility between the yoke and the chassis. Yes, it may have been working before, but going from a 19K7900 to a 19K7300...probably doesn't like it.

[shawnbo42]

Yoke and chassis haven't been mixed and matched. I took the entire monitor out (7302), as in tube, yoke,chassis,frame, everything.
I then replaced it with a complete, previously working k7000. Again, frame, chassis, tube, and yoke.
This is the part I don't get. The only 3 connections I plugged in were RGB/Ground/sync, AC power, and the frame ground, so pretty much the ONLY thing that changed was the monitor....And, if memory serves, it was originally a k7000 to start with. (That one died a long time ago, and the 7302 was put in place of it.)

[shawnbo42]

Ok, so I finally got around to working on this project again, and what a project it's turning out to be. Here's the long and short of it. I plugged another board into the L.E. cabinet (Great 1000 mile rally), comes up with a pic on screen, although out of sync, due to res. issue. BUT, the point is, I had a picture, fully working, no problem. I checked my line voltage previous to this test (119.9), and checked my video signal lines all the way back to the board (everything is fine, no broken wires, loose connections, etc.). So, I have HV to the tube, neck glow, my L.E. board gives me the white box screen just before the game, and BAM, the picture's gone.

So, I figure my video output on the board is bad. Plug the lethal enforcers in to my Neo Geo right next door, and it boots up perfect, flawless picture and everything. So, what I've got now is a Lethal Enforcers board, tested and working in another cab, a 2nd board in the Lethal Enforcers cabinet that shows a picture just fine, a monitor that is now doubly tested and known to be working, and all the wiring is proven to be good, as well as good line voltage, iso x-former, line filter,etc (due to the fact that the monitor displays a picture on a different board flawlessly). I am out of ideas completely at this point.What could the problem possibly be?