Bought a 'dead' cab & trying to figure: is monitor bad or is it something else

[quarterback]

I just bought a non-working Kanomi cab with a Wells Gardner 19" monitor model number: 19K5401 manufactured in Sept 1987   It's a jamma machine and the jamma board looks very clean although the monitor and glass on the game is filthy.

When the machine is powered up, there is a visible glow in the corners of the monitor, but they fade and no picture ever comes up.  When powered off, a 'rectangle' of grey light fades out on the screen.

The marquee doesn't light, although it could be a burnt out fluorescent tube.  The coin returns have bulbs in them, but they don't light either.

My first thought was that the monitor is bad, but since NOTHING lights up, I'm wondering if it's a power supply (or some other) issue.  This is my first arcade machine, so I'm not sure where to start or how to test this.  Heck, I don't even know what everything inside the cab actually does.

I figure I'll buy a new fluorescent tube tomorrow and check that, but it seems like there are multiple reasons that any one of these things might not be powering up.  

I read through the last few months of posts here looking for tips, but the most relevant thing I've found is the suggestion to check out "Randy Fromm's Secret Technical Department" which I can't seem to access.

So I'm hoping somebody can advise me.  Does the momentary screen lighting at the corners mean anything?   Is there some specific voltage I can check at various points with my multi-meter that might help me troubleshoot?
Thanks

[Ken Layton]

http://randyfromm.com/amusements/techdept

That should get you into the tech dept.

I think your monitor is probably ok and you have a bad power supply.

Get a voltmeter and start checking voltages. Check for correct voltage going into the power supply. Then check for proper voltages coming out of the power supply.

[quarterback]

http://randyfromm.com/amusements/techdept

That should get you into the tech dept.

Yeah, for some reason the link to the 'secret tech dept' gives me a "The page cannot be displayed" error.  There is a disclaimer under the link that says "(seems to work with Internet Explorer only)" but even though I'm using IE, it still doesn't work for me.

I think your monitor is probably ok and you have a bad power supply.

I was hoping somebody might say that  but I won't start counting my chickens just yet.

Get a voltmeter and start checking voltages. Check for correct voltage going into the power supply. Then check for proper voltages coming out of the power supply.

Part of my problem here is that I'm not completely clear about what the three 'boxes' at the bottom of the cabinet are or how everything operates

Here's a picture of a cab like mine (not my pic, but the same cab)


(1) This has a piece of paper over it that says something like "warning 120v"
(2) Some kind of transformer?
(3) Black metal box that seems to have a "vol" dial on it.

I could pull off the paper at #1 and test the voltage there, or should I do it one one or the other side of #2? And what kind of readings should I be looking for at #2?  And what about #3?

#s 4, 5 & 6 are other issues.  #4 is a silver woven/braided 'cable.  I'm assuming it's a ground, but mine is connected to the wall of my cab, but NOT on the other end.  Should it be attached to the monitor frame?  The woven-wire has a hole in the unattached end and my guess is that it's just come off of something.

#5 there is a black insulated wire running around this area of my monitor.  It's been crudely twisted together (two pieces now attached with a bare twisted end poking up)  I'm afraid to touch it.

#6 This is the 'door switch' (I'm sure there's a real name for this) I figure I could test voltage here because this switch keeps the monitor from powering up.  Or would I even get voltage here?  It could be controlling a disconnect and not the monitor-power itself, I just don't have that knowledge.

Thanks again

[Ken Layton]

# 3 is the switching regulator power supply that runs the game board and coin door lights. You'll probably need to unfasten it from the bottom of the cabinet so that you can tip it up to where you can get at the terminal strip in order to put your voltmeter on it.

Try this other link for Randy Fromm:

http://slot-tech-ftp.serveftp.com:8080/

[quarterback]

# 3 is the switching regulator power supply that runs the game board and coin door lights. You'll probably need to unfasten it from the bottom of the cabinet so that you can tip it up to where you can get at the terminal strip in order to put your voltmeter on it.

Thanks.  I'll check that later today.

Try this other link for Randy Fromm:
http://slot-tech-ftp.serveftp.com:8080/

That's the link on that page that I'd been using and it wasn't working... but now it is.

So that's cool, that page and your replies make me think I may have been right by assuming "no lights" meant there might be some hope for the monitor.  

I'm still worried about the black wire that's just twisted together.  And I'm still not sure about where/what everything is inside my cab.  Is there a good 'cab innards' link I've not found?

Also, I went to the http://arcarc.xmission.com/PDF%20Monitors/ page but couldn't find a manual for my monitor.  Nor could I find any reference to the K5401 when I googled it and I'd like to have a better idea of what everything is.  Is the K5401 unheard of? Uncommon?  Or similar enough to another model that I could use a difft manual?

Thanks again

[Ken Layton]

Do you have a closer view of the monitor's main circuit board? It looks like a k7000 model. That #5 black wire is the picture tube ground wire going to the neckboard. It's been cut before which means someone had the circuit board out for service. This particular black wire must be cut in order to get the circuit board out. Naturally after the circuit board was replaced/repaired, that wire needed to be reconnected. So whoever did the work merely stripped the ends and twisted them together. When I repair these chassis I put a male & female quick disconnect terminals on this wire to make future repairs easy.

[quarterback]

Thanks for all your help on this Ken.

I'll take some close-up pics tonight or tomorrow.
Thanks

[fredster]

Stupid question, did you try playing the game blind?

That is, let it boot up and then drop quarters and listen to see if it's working?  Hit the start button, etc?

You could also put a volt meter on the output from the game and check for up to +5v DC from the red output to the video ground to see if you are getting a video signal.

[quarterback]

# 3 is the switching regulator power supply that runs the game board and coin door lights. You'll probably need to unfasten it from the bottom of the cabinet so that you can tip it up to where you can get at the terminal strip in order to put your voltmeter on it.

Okay, I finally got to this and it looks like that's at least part of the problem.  I took my voltmeter to it and got the following:

212v AC across the two terminals marked "AC"
4volts from the 12v terminal
~1.6volts from each of the +5v terminals.

This is wrong, no?  I should be getting 12v from the 12v and 5v from the 5volt terminals, right?

Also, I noticed that two (of the 4) coin-return lamps WERE lighting up... barely.  They were registering ~1.6volts.  

So, based on this info, should I assume that the switching power supply is bad?  Do I need to replace it?  Is there any way to repair it?

Stupid question, did you try playing the game blind?

I did, and I got nothing.   But it's not a stupid question, I only tried it after finding some other thread where somebody mentioned it.  I'm a total newb at this and have far more questions than answers, so I'll take any suggestions you've got.

BTW, is there a good link for info about the coin-mech?  How it works?  How to change it from quarters to tokens to whatever?  3 of the 4 take quarters and reject tokens.  The 4th one 'jams' with either and I'd like to fix that.

You could also put a volt meter on the output from the game and check for up to +5v DC from the red output to the video ground to see if you are getting a video signal.

I could try that but I'm not sure where that is.  Is the video ground part of the jamma connection or is it elsewhere on the board?  I'll go search and see if I can figure it out.

Thanks

[quarterback]

Okay, the update is: The monitor works.  

I replaced the cabinet's existing power supply with a PC power supply, the game booted up and I got an image on the monitor.

There's no burn in although the colors at the top might be a little off (hard to say, I'm not familiar with the game) and I think the whole thing looks a little washed out.   I'm guessing that the answer is: "cap kit"

For now it's fine with me, but I was wondering if anybody can confirm the model of the monitor.   Like I posted earlier, the tag says K5401  Here is a pic