Another MK cab, another problem

[Malenko]

Bought this cab for $250, its an MK4 painted Black with Deer Hunter USA installed.  Screen has a white bar on the side that I cant get to go away via adjustments.


Any and all help is GREATLY appreciated.

[grantspain]

what monitor make/model is it?

[Malenko]

its tied to the factory wiring, and since its an MK cab, Im assuming a WG. No labels I can see, but I did snap this pic for ya

[grantspain]

u5000 or k7400 or u2000 by the looks of things
i would start at capacitors

[Malenko]

u5000 or k7400 or u2000 by the looks of things
i would start at capacitors

figured as much. Is this a common or even a known issue?

[grantspain]

remove the video signal plug and turn up the screen volts a bit so you get a white raster,post the photo here

[Malenko]

remove the video signal plug and turn up the screen volts a bit so you get a white raster,post the photo here

This good enough?


Didnt increase the volts but did remove the video source.

[grantspain]

hmm that is a strange fault,i have seen similar issues to that on hantarex polo and its caused by a resistor on the G2 circuit(on the neck card)

[twistedsymphony]

Here's a comparison guide I wrote for determining which WG chassis model you've got: http://forums.arcade-museum.com/showthread.php?t=267353

based on your pictures it's probably a k7400 (you can confirm based on the chassis code)

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IIRC these  monitors are notorious for burning up the traces on the neck board... it looks like your neckboard has never been touched, it couldn't hurt to reflow the joints there and do a cap kit just for a baseline

there are LOTS of people who repair these chassis so worst case it wont be hard to find someone to fix it if you can't.

[Malenko]

Here's a comparison guide I wrote for determining which WG chassis model you've got: http://forums.arcade-museum.com/showthread.php?t=267353

based on your pictures it's probably a k7400 (you can confirm based on the chassis code)

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IIRC these  monitors are notorious for burning up the traces on the neck board... it looks like your neckboard has never been touched, it couldn't hurt to reflow the joints there and do a cap kit just for a baseline

there are LOTS of people who repair these chassis so worst case it wont be hard to find someone to fix it if you can't.

Thanks, I'll try to reflow the neck tonight, I already emailed bob about cap kits. I'll update this thread if I make any progress.

[Malenko]

based on your pictures it's probably a k7400 (you can confirm based on the chassis code)

Frame said WG25K2193, took a picture of the stick just to be sure.  Neck board was cracked a little, I hacked it a bit with solder and wire, the white area is still there but I feel better about the neck now. I'll finish recapping it tonight and go from there.

appreciate all the advice so far, feel free to keep it coming.

[twistedsymphony]

I wouldn't trust any labels outside of the main chassis board itself. Who knows what a former owner might have swapped in/replaced, especially since most of those WG chassis are cross-compatible with the tubes and yokes from other monitors. Swapping a broken chassis for a different model working one would have been trivial.

look for the "P" number silkscreen on the chassis along the edge, it should identify it beyond any doubt you can look it up i that thread I posted earlier.

a "25K2193" which is a u2000 chassis will be "P717"
a k7400 will be "P763"

based on the location of your width coil I still think it's a k7400 and not a u2000 despite what the frame says.

I hope for your sake it's a k7400 as the u2000 is notorious for being a turd

(full disclosure I have a u2000 in my ki2 cab, and it's fine, but I did have to completely rebuild it)

[MK3FAN]

Factory MK4 cabs came with a K7400. As for your White area, I hate to say it but that looks a lot like a picture tube problem. If your chassis ends up being a K7400, you can install it on a K7000 tube and verify if your problem is a tube issue or a chassis issue. My money is on the tube.

[Malenko]

Factory MK4 cabs came with a K7400. As for your White area, I hate to say it but that looks a lot like a picture tube problem. If your chassis ends up being a K7400, you can install it on a K7000 tube and verify if your problem is a tube issue or a chassis issue. My money is on the tube.

Welp I see no markings on the board, and Im assuming the label is wrong and or the chassis was swapped onto this tube.

I pulled out the monitor and these are the best pix I can take of the chassis:

[MK3FAN]

Factory MK4 cabs came with a K7400. As for your White area, I hate to say it but that looks a lot like a picture tube problem. If your chassis ends up being a K7400, you can install it on a K7000 tube and verify if your problem is a tube issue or a chassis issue. My money is on the tube.

Welp I see no markings on the board, and Im assuming the label is wrong and or the chassis was swapped onto this tube.

I pulled out the monitor and these are the best pix I can take of the chassis:

054A7401 = K7400

The number on the tube indicates a K7000 was once installed, but it will support a K7400 as well so there's no issue there. Measure the yoke windings on your Polo tube (should be roughly the same) and install this chassis on the Polo tube to eliminate the chassis as your issue.

[Malenko]

I'll try that tonight.

[Malenko]

ok swap the chassis over, I guess the good news is its not the tube?

[twistedsymphony]

very good news if it's not the tube... tubes are hard to find since no one wants to ship them .... absolute worst case now is you buy a new chassis.