Gauntlet Legends K7500 Help

[rikitheshadow]

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?

Ya thats one thing I forgot to mention that in some semi rare cases the pots are bad and creating too much noise. I'd give that remote a good check with the multimeter.

On that continuity check on the grounding in the cabinet, just simply unplug it, hook one of the test leads to ground prong on the cord and another to the metal frame of the monitor. See if it checks out.

 

[vipe155]

Ya thats one thing I forgot to mention that in some semi rare cases the pots are bad and creating too much noise. I'd give that remote a good check with the multimeter.

On that continuity check on the grounding in the cabinet, just simply unplug it, hook one of the test leads to ground prong on the cord and another to the metal frame of the monitor. See if it checks out.

The ground seems to be good. What would I check for on the remote board?

 

[modessitt]

The 7500 doesn't have a horizontal hold pot on the remote board. it is located on the chassis in the back middle right...

http://www.wellsgardner.com/pdf/Board/K7500_25_27_inch.pdf

 

[vipe155]

The 7500 doesn't have a horizontal hold pot on the remote board. it is located on the chassis in the back middle right...

http://www.wellsgardner.com/pdf/Board/K7500_25_27_inch.pdf

Yeah, thats what I've been adjusting on this. The picture wants to go diagonal, and it seems like that pot needs to be in just the right spot to get a straight, even picture. I don't know if replacing it or any of the remote board pots would do anything for this.

 

[modessitt]

Try replacing Q700 and maybe D700. You may need to replace U701...

 

[vipe155]

Try replacing Q700 and maybe D700. You may need to replace U701...

That would be a 2N3904 on Q700, and a 1N914B on D700? I can get the Q700 part locally, so I guess I'll try that first. Failing that, I'll order the other stuff in. Thanks for the suggestions.

 

[gamefixer]

both videos look to me like the signal ground is bad or not connected. Unplug the signal cable from the monitor and use a multimeter to see if you get +4.0VDC or better between the sync pin (the white wire) and the ground pin (should be pin 4 of the connector). If you do then I guess those wires/signals are good. You could also check between GND and the color signals but those will only measure around half a volt to slightly above a volt.

Could also be a bad sync generator on the game board. Best way to tell would be to try another medium res signal on the monitor.

You might also be able to see if its the monitor by removing the signal cable and slightly turning up the screen control (the knob on the bottom of the flyback) until the screen is grey. If the raster seems to be jumping around as it does when the game is connected to the monitor then you have a monitor problem. If not you have a board/harness problem.

My vote is that SYNC isnt hooked up to the right pin or your video GND is bad/not hooked up to the right pin.

 

[vipe155]

both videos look to me like the signal ground is bad or not connected. Unplug the signal cable from the monitor and use a multimeter to see if you get +4.0VDC or better between the sync pin (the white wire) and the ground pin (should be pin 4 of the connector). If you do then I guess those wires/signals are good. You could also check between GND and the color signals but those will only measure around half a volt to slightly above a volt.

Could also be a bad sync generator on the game board. Best way to tell would be to try another medium res signal on the monitor.

You might also be able to see if its the monitor by removing the signal cable and slightly turning up the screen control (the knob on the bottom of the flyback) until the screen is grey. If the raster seems to be jumping around as it does when the game is connected to the monitor then you have a monitor problem. If not you have a board/harness problem.

My vote is that SYNC isnt hooked up to the right pin or your video GND is bad/not hooked up to the right pin.

I just tried what you suggested, and I get only .3V between pin 4(ground) and pin 6(sync). I get .5V to .7V from ground to the color pins.

What do I need to do to fix this if that is indeed the issue?

 

[gamefixer]

Not a rock solid check but see what you get between the video gnd pin and +5 from the power supply. It may be an isolated GND so you may get nothing but I'm not sure. You should also check continuity between the JAAMA video GND pin and the monitors video GND pin to make sure that the video GND wire is good.

You checked for those voltages with the meter on DC right?

 

[vipe155]

Not a rock solid check but see what you get between the video gnd pin and +5 from the power supply. It may be an isolated GND so you may get nothing but I'm not sure. You should also check continuity between the JAAMA video GND pin and the monitors video GND pin to make sure that the video GND wire is good.

You checked for those voltages with the meter on DC right?

Yeah, those where checked on DC. .3 between ground/sync, .7 up to 1 on the color wires. The video ground pin seems to be good, it reads 5V with the black lead on that ground pin and the red lead on a 5V wire on the PS.

 

[gamefixer]

Kinda sounds like the JAMMA I/O board is bad. OR, and this is a big OR. I suppose that the video card could be bad?? Maybe its not outputting the SYNC signal correctly.

 

[Buffett]

the gauntlet my friend has did kinda the same thing with the red. his video card was loose and was not making connection. after it was reseated every thing was fine.

try unpluging it clean the contacts and try it again.

Peace
Buffett

 

[vipe155]

Kinda sounds like the JAMMA I/O board is bad. OR, and this is a big OR. I suppose that the video card could be bad?? Maybe its not outputting the SYNC signal correctly.

I have a 2nd video card, and they both do the same thing, so that's not it. I don't know about the I/O board, but the game passes all tests when you turn it on, and the game plays perfectly fine behind the monitor issue.

I would think if the whole board was bad it wouldn't play the game correctly, but maybe I'm wrong. The Jamma harness was hacked up some, maybe it needs some work.

 

[demogo]

Vipe, if you have access to any other standard res monitor, flip the dip switches on the board to output a standard res monitor and test with it.

That'll give you some clues as to whether your problem is the monitor or boards.

 

[vipe155]

Vipe, if you have access to any other standard res monitor, flip the dip switches on the board to output a standard res monitor and test with it.

That'll give you some clues as to whether your problem is the monitor or boards.

I wish; this is the only arcade I own. I have nothing to compare anything to. It's not fun trying to figure out is it the game? Is it the monitor? WTH? etc.

 

[demogo]

I wish; this is the only arcade I own. I have nothing to compare anything to. It's not fun trying to figure out is it the game? Is it the monitor? WTH? etc.

Well, a solution to this test problem is very easy... you know what to do.

Another approach -- where exactly in Missouri are you? Perhaps there's some friendly KLOVers in your area that can come over with a spare standard res monitor and do said test.

 

[vipe155]

Well, we can officially close the book on this. I looked through a .pdf of the manual and went through both boards. I had bought this game without a monitor, and with everything kind of scattered around.

In looking at the manual, I found that the jumper was installed on the positive/negative sync pins (perhaps a different brand/type of monitor used to be installed in this, IDK), with positive being the default option and negative being the jumpered option. Take the jumper off, game fixed.

I guess I should feel pretty stupid about this. At least I capped the monitor (it looks great), and the game works. Thanks everyone.

 

[gamefixer]

Just goes to show you that the auto sensing function of newer monitors doesnt work as advertised. That K7500 is supposed to be able to sync to positive or negative sync on its own no matter where you have the sync wires connected.

Glad you got it working. Thats a pretty cool game.

 

[modessitt]

I believe he means he had it connected to the vertical and horizontal, and disconnected the vertical. I guess I wasn't clear way back in my first response in this thread (just checked and I wasn't) when I mentioned the sync needed to be connected to the negative, but I guess I assumed the connector was already configured for the WG and would only have one sync wire on pin 10.

This is a good example of why we should get people to post pics of their sync wiring when they have issues like this...

 

[vipe155]

I believe he means he had it connected to the vertical and horizontal, and disconnected the vertical. I guess I wasn't clear way back in my first response in this thread (just checked and I wasn't) when I mentioned the sync needed to be connected to the negative, but I guess I assumed the connector was already configured for the WG and would only have one sync wire on pin 10.

This is a good example of why we should get people to post pics of their sync wiring when they have issues like this...

I don't know that we are talking about the same thing. Here is a picture of the page in the manual. The only change I made was taking the jumper off J2 on the I/O board. It was installed, therefore on the "Negative Sync" setting.