Gauntlet Legends K7500 Help

vipe155

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I am putting back together a project Gauntlet Legends, and I just got a WG K7500 27" for it. I hooked up the power & video wires, and when powered on the picture is diagonal. Color seems fine, but there are a couple of black diagonal bands with the game playing inbetween.

I have no pictures or documentation on how this monitor should be grounded, so it's not grounded anywhere but the power plug. All the game dip switches are set correctly.

What could be the issue with this?

Edit: After messing with the screen adjustment pots, this is as good as I was able to get it right now:

http://www.youtube.com/watch?v=7vXtKqn_Kw0

The colors are messed up, and it's bouncing horizontally enough to make you sick.

EDIT 8/12: UPDATE on 2nd Page.
 
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Just a little update/question about monitors.... I have no idea what I'm doing with these, except that they look extremely complicated and dangerous to me :)

Would adjusting the focus do anything with this? Is this a H. Hold issue, and why doesn't the remote board for one of these have a pot for H. Hold?
 
You can try adjusting your horizontal hold to see if it helps, and make sure you have the sync connected to the negative sync pins (GL is JAMMA right?).

You may need to cap this monitor...
 
You can try adjusting your horizontal hold to see if it helps, and make sure you have the sync connected to the negative sync pins (GL is JAMMA right?).

You may need to cap this monitor...

Ok. GL is Jamma, and could you describe a little bit where the negative sync pins are/where they go? I'm sorry for being so monitor stupid. This is the only arcade game I've actually done any work on.

Edit: I see in the schematics there is one wire for video-sync, but I don't see negative sync.
 
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mod, does it matter that all the sync pins on the K7500 say +/- by them? lol

must explain why I had that NBA Jam JAMMA harness in my supergun that I plugged into a U5000 and it worked on the other sync pin instead of pin #5.
 
Ok, I got the ground wire run from the marquee bracket, to the CPO to the monitor chassis.

Right now, the picture on the game is blurry, and it still jumps some back and forth like in the video. Also, I noticed that the game has white lines showing up through objects in the game. Would a monitor cause that, or is it a video card issue? The game isn't seeing the video card as bad during the test, but I don't know why the monitor would cause artifacts like that.
 
mod, does it matter that all the sync pins on the K7500 say +/- by them? lol

must explain why I had that NBA Jam JAMMA harness in my supergun that I plugged into a U5000 and it worked on the other sync pin instead of pin #5.

It shouldn't, but the other day I accidentally hooked up a positive separate sync game to a 7400 and has it on negative sync by accident. i got a picture, but it was bowed slightly and the horizontal hold was a little shaky. Moving it to positive gave me a better pic, even though the input is about the same as the 7500. It's something to check at least...
 
It shouldn't, but the other day I accidentally hooked up a positive separate sync game to a 7400 and has it on negative sync by accident. i got a picture, but it was bowed slightly and the horizontal hold was a little shaky. Moving it to positive gave me a better pic, even though the input is about the same as the 7500. It's something to check at least...

The game seems to use "Comp Sync" only, and it's connected to that currently. Going by the schematic, and the monitor information, the video input is correct.
 
That makes me a little nervous, not working around a monitor before. I guess I'll order one.

It's typically much cheaper and easier to have an existing one repaired by someone else.

I got hosed when I tried to do this very same thing on my GL cabinet but I think I'm the exception rather than the rule here.

If I could do it all over again I'd have sent my chassis to WG for repair.
 
It's typically much cheaper and easier to have an existing one repaired by someone else.

I got hosed when I tried to do this very same thing on my GL cabinet but I think I'm the exception rather than the rule here.

If I could do it all over again I'd have sent my chassis to WG for repair.

I mean, it's not that I can't do the board work. I've done alot of it on my pins. I'm just afraid of going through the whole discharge process, and any other complications. I'm not in the mood to injure myself....

What kind of issue did you have?
 
dude, the discharge process is kindergarten shit. clown shoes. I grab a flathead (preferably with a squared base for better grip), and alligator clip, and uh, I bring my hand to lift the suction cup part open, clip to the monitor frame, touch the screwdriver to the anode pins and uh... that's it. then you just pop it off. it's not going to blow you into the next world if you touch it either, I've been zapped by one of those fresh. you will have to repeat discharging, cause the static on the back of the tube creeps back in the anode hole. you might just get lucky and it'll mostly discharge itself if you leave it off long enough.

I do this seriously almost daily. and I've done it numerous times on those Midway cabs where you can't directly access the monitor cause there's a support wall in the way. heh
 
dude, the discharge process is kindergarten shit. clown shoes. I grab a flathead (preferably with a squared base for better grip), and alligator clip, and uh, I bring my hand to lift the suction cup part open, clip to the monitor frame, touch the screwdriver to the anode pins and uh... that's it. then you just pop it off. it's not going to blow you into the next world if you touch it either, I've been zapped by one of those fresh. you will have to repeat discharging, cause the static on the back of the tube creeps back in the anode hole. you might just get lucky and it'll mostly discharge itself if you leave it off long enough.

I do this seriously almost daily. and I've done it numerous times on those Midway cabs where you can't directly access the monitor cause there's a support wall in the way. heh

I understand it's simple to you, but exposed components and warning stickers may give a newbie pause. Even so, I'm sure I'll be fine.

Why do they say it could kill you if it doesn't? Everybody seems to have been shocked at one point.
 
I mean, it's not that I can't do the board work. I've done alot of it on my pins. I'm just afraid of going through the whole discharge process, and any other complications. I'm not in the mood to injure myself....

What kind of issue did you have?

Symptoms were drifting focus so it was likely a bad flyback.

Repair person identified and fixed several other issues including replacing the neckboard and some other components. When it came back to me the monitor was acting as if it were a 7502 instead of a 7501 and had horrendous uncorrectable pincushion issues that didn't exist before.

After spending a bunch of money to try to fix the new problems after spending a few hundred bucks fixing it initially, I threw in the towel and bought a new monitor because I was dying a death of 1000 cuts.

In retrospect I wish I'd just have sent it to WG in the first place for repair but I had no idea they did repairs.

Discharging the monitor isn't bad but is scary the first time you do it. After that it's very routine and no big deal, really.
 
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Okay, then rebuild the monitor if it hasn't been done already...

Alright, I rebuilt it using a k7500 cap kit, and this is as good as it gets:

http://www.youtube.com/watch?v=21AUuALriLA

Still jumps horizontally, I have to mess with the H. Hold pot a bunch just to get it this "good." On the bright side, the colors look better, and with some adjustment this would probably look good in that regard.

So, if everything is hooked up properly, voltages are good, and it's been capped, what's wrong with this?
 
Alright, I rebuilt it using a k7500 cap kit, and this is as good as it gets:

http://www.youtube.com/watch?v=21AUuALriLA

Still jumps horizontally, I have to mess with the H. Hold pot a bunch just to get it this "good." On the bright side, the colors look better, and with some adjustment this would probably look good in that regard.

So, if everything is hooked up properly, voltages are good, and it's been capped, what's wrong with this?

Possibly the flyback causing issues? Does the flyback have white or black adjustment knobs for the focus and screen? Also try unplugging the cabinet and running a continuity check on the ground throughout the cabinet....see if the monitor is truly earth grounded.

I suggest pulling it out also and checking for cracked solder joints. Reflow anything that looks bad or burnt because K7000s commonly have issues with the large resistors frying traces. (read from the sticky)

I'm no expert and have had very few experiences with repairing monitors, but I've been reading up on these things a lot here on the forums to get a general idea of what to look at in common situations, but its certainly not uncommon to encounter a picky piece of equipment.
 
Possibly the flyback causing issues? Does the flyback have white or black adjustment knobs for the focus and screen? Also try unplugging the cabinet and running a continuity check on the ground throughout the cabinet....see if the monitor is truly earth grounded.

I suggest pulling it out also and checking for cracked solder joints. Reflow anything that looks bad or burnt because K7000s commonly have issues with the large resistors frying traces. (read from the sticky)

I'm no expert and have had very few experiences with repairing monitors, but I've been reading up on these things a lot here on the forums to get a general idea of what to look at in common situations, but its certainly not uncommon to encounter a picky piece of equipment.

It has the black knobs, not the white. Where would I check on the machine/monitor to see if the whole thing is grounded properly? Right now the chassis is connected to the CPO hinge, and I have the tube ground wire going to the neckboard like it should.

I didn't remember seeing any obvious solder/trace issues when I had the chassis out, but I can check that if this other stuff goes nowhere. I was actually wondering if the Horizontal Hold pot is any good on the main board, or maybe the remote board is bad somewhere?
 
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