Arcade Collecting > Miscellaneous Arcade Talk
How to start finding board and monitor problems?
APFelon:
--- Quote from: unclet on March 06, 2005, 07:41:50 pm ---I understand what you mean to test for 110Vac, but as to where to place the probes, I have not a clue. I am not sure where 110Vac should be going into a monitor or going into the filter. Actually, not sure what you mean by "leads into the power supply board" either. There is a molex connector with many wires going into the power supply board ..... do your mean test a couple of these wires or something different?
I do see the 3 Pots on my Power Supply board. The diagram in the PDF of the power supply board shows the Pots are -5V, +12V and +5V. Should I check for these positive and negative values, or should they all have 110vac? Basically, what is the difference between V an vac? Not real sure where to put the probe on the wires leading into the pots either ..... I will try to play around with it.
I just got back in from the garage trying to probe around loking for 110vac (before reading your latest reply), and I felt like a real idiot and having no idea where to put the probes. I gave up. I will retry again and see if I feel any smarter ...... :)
I feel bad about this, but I am also laughing a bit as well at how inept I am at even understanding what most of you consider trivial stuff. Hopefully you will continue to hang in there with me before going completely mad..... :P
--- End quote ---
Heh, we all have to start somewhere. Thank God you have a "screw around" machine to toy with. Well, let's start with the basics.
When I say "VAC", that stands for "Volts Alternating Current", or the stuff that comes out of your wall. An arcade machine power supply (or a computer power supply) takes that current and turns it into something that is OK for a circuit board, or "V" (volts, understood to be DC or "direct current").
There are a few things that use VAC in your cabinet. The monitor uses it and the marquee lights use it. Everything else is converted by the power supply (the circuit board, the coin lights, any motors the machine may have, etc). SO, you put 110 VAC into a power supply, and it spits out +5v, +12v, -5v, etc. (if working correctly).
So in essence, you need to get the 110 VAC to three things in order for the game to work as intended. The coin door switch that you have will kill the 110 to everything on the other side of the switch, so if it is "open", it'll look as though the game is completely dead-- no marquee, no monitor, no game. The wall voltage will stop at that switch, and no current will go anywhere.
To see how to measure for 110, go ahead and stick the leads in to the wall socket. It'll register as 110VAC. Next, plug in the game and follow the cord to the next "step" in the circuit, in this case the filter. Check the VAC on the other side of the filter. You should get 110 VAC there, too. If not, you may have a break in the wall cord. This can sometimes happen if the cord gets pulled or crushed, so it is a possibility.
Now follow the two wires to the next step in the chain (skip the isolation transformer, as I doubt that it is bad). It should be the door kill switch. Close the switch (you can probably pull the switch out so it says "on" while you have the door open) and check there. If you get no voltage there, the switch is probably bad.
Other places to check for AC- The monitor should have a thick black cord running up to the monitor that can be detached at a Molex plug. Detatch the Molex and stick the probes into it, and look for 110.
So, where do you put the probes? Well, I would take an alligator clipped wire and attach one end to the black probe of your multimeter, and the other end to the green wire lead on the right hand side of your filter. That is known as the "field ground" and it should be okay for your ground as long as your line cord has that third prong on it. The red probe is the "live" probe and you use that on places that should have juice.
Just remember, be careful when you are probing the 110. Once we get through this part and start looking at the 5v, 12v, etc, the shock hazard will be minimal. But 110 is the wall voltage, and if you take a zap, it'll sting.
I hope this helps and you find the problem (but I have a feeling that this is just the beginning). Just keep me updated and I'll help the best I can.
APf
unclet:
Thank you for your patience ..... :) Yes, part of the reason why I am giving this a try is because the cabinet was a FREE one. I would be scared to mess up a valued cabinet just to play around with...
Ok, I think my confusion is that I am misunderstanding your naming of the parts of my machine. I think I have now learned what you are referring to, but I want to make sure......
Is the silver box in this photo the "filter/silver thing" you referred to? The wires which come from the plug in the wall go into this little silver box thing. If so, then are you saying to place my black probe on the green wire there and then place the red probe on one of the remaining two wires going into this filter? Also, if that is a correct description of what you are saying then I guess you also are telling me to test the blue and brown wires coming out of the other end of the filter as well? If so, then assuming I keep my black probe on the green wire going in to the filter, then which of the two wires remaining (blue or brown) should register the 110Vac.
Also, in the picture below, is the round thing with all the wires coming from it represent the isolation transformer only?
Next, when you say the next step from the filter for the 110vac route is the switch on the backdoor ... to basically just follow the wires to it .... seems to be a problem since the blue and brown wires coming from the other side of the filter lead into the isolation transformer and a bunch of wires come out of it, thus making it hard to follow to the switch. Anyway, there are two wqires on the switch. Most likely a wire connected to "Normally Open" and one connected to the "Common" of the switch. Are you saying these two wires are going to have 110vac going through it.
Oh yeah, also, the switch which "kills" everything seems to be located against the "backdoor wood" panel. when I take off the back door wood panel, the switch button pops out. When the door is replaced, the button gets pushed in. I have no coin door or coin mechs at all, in this cabinet, so there are no switches related to a coin door.
Ok, enough talk, I am going to play around now ......
PS: I still feel stupid at this point, but hopefully that will change.
unclet:
and ..... is this complete board called to "Power Supply"
APFelon:
--- Quote from: unclet on March 06, 2005, 08:49:29 pm ---
Is the silver box in this photo the "filter/silver thing" you referred to? The wires which come from the plug in the wall go into this little silver box thing. If so, then are you saying to place my black probe on the green wire there and then place the red probe on one of the remaining two wires going into this filter? Also, if that is a correct description of what you are saying then I guess you also are telling me to test the blue and brown wires coming out of the other end of the filter as well? If so, then assuming I keep my black probe on the green wire going in to the filter, then which of the two wires remaining (blue or brown) should register the 110Vac.
--- End quote ---
I'm not too sure. I have been spoiled on the black/white/green color code of modern games, and my pre-JAMMA skills are a bit wanting, so I'm not too sure on how the wires are color coded. But that doesn't matter, you can find out for yourself. Test them both. One of them should give you 110, and then you know which color wire is "live" with 110 in your cabinet.
--- Quote ---Also, in the picture below, is the round thing with all the wires coming from it represent the isolation transformer only?
--- End quote ---
Yep, that's the monster.
--- Quote ---Next, when you say the next step from the filter for the 110vac route is the switch on the backdoor ... to basically just follow the wires to it .... seems to be a problem since the blue and brown wires coming from the other side of the filter lead into the isolation transformer and a bunch of wires come out of it, thus making it hard to follow to the switch.
--- End quote ---
That shouldn't matter, either. You know where the 110 is supposed to be, there should be no need to chase the wires coming out of your isolation transformer (unless there is a break, which is improbable).
Think of it this way. You tell a friend "Leave your home and meet me at the bar". You don't need to meet your friend at his home and follow him to the bar, you know he will meet you at the bar. Same thing with the voltage. If the 110 is coming from the filter, just go to the next place it should be (the kill switch).
Man, I hope that made sense.
--- Quote --- Anyway, there are two wires on the switch. Most likely a wire connected to "Normally Open" and one connected to the "Common" of the switch. Are you saying these two wires are going to have 110vac going through it.
--- End quote ---
Yes, it should. If it doesn't, that's where your problem is.
If this switch is like the ones found on other Midway games of that era (Pac Man et. al), the switch has three positions. "in", which is when the back door is closed, "out", which is when the back door is open, and "way out", which is when you pull on the switch. While you are doing your testing, give the switch a firm tug in order to close the circuit and check for voltage.
--- Quote ---Oh yeah, also, the switch which "kills" everything seems to be located against the "backdoor wood" panel. when I take off the back door wood panel, the switch button pops out. When the door is replaced, the button gets pushed in. I have no coin door or coin mechs at all, in this cabinet, so there are no switches related to a coin door.
--- End quote ---
The coin switches shouldn't matter. I know Paige mentioned that Sprint had issues of the coin switches were removed, but I have never heard of this on any 80s-era games. But who knows? It is possible. But since you aren't getting 110, we don't have to concern ourselves with that just yet.
--- Quote --- PS: I still feel stupid at this point, but hopefully that will change.
--- End quote ---
Don't. When it comes to technical issues, I am not exactly Mr. Clarity so your confusion is understood. Here is a labeled photo so we can be on the same page.
APf
unclet:
Ok ...... success has been made!
When I stuck the probes into a regular plug outlet, then my V-Ac reading was 125V-Ac.
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