Tech Help on Freddy Nightmare on Elm Street or any System 3 pins

Black Matrix

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Tech Help on Freddy Nightmare on Elm Street or any System 3 pins

Hey All,
I have a Freddy that I have thoroughly buggered up. But the issue I want to fix is very simple. On the A2 power supply board (the one that converts 12 volts unregulated DC to 5 volts DC), there is a very crappy 500 ohm adjustment pot. I was wondering if anyone had a source for an improved version of this very problematic pot. I have looked at Bob Roberts who has 2 or 3 different pots, but none fit the bill. So has anyone replaced this pot. If so, what did you go with. Do you have a part number and a source. Ideally, I would like to find a fine tune adjustment pot that can be dialed in to be very accurate. For those who don't know about this problem, the pot is crappy. The 5 volts creep low or high and the Pin resets for no reason or it never boots due to the 5 volts not being there. Here is a link that talked about it before:
http://forums.arcade-museum.com/showthread.php?t=118871&highlight=freddy

But so far, I haven't found anyone that has a good fix. But I'm still looking. Its off to Rec.games.pin next. Just thought someone on here may have encountered and bested this problem in the past.

For what its worth, the pots footprint is 3/16ths by 1/8th inch. Currently, it has a universal F-type pot bent and mounted in a vertical fashion with a thumb wheel adjustment.
Here's Bob Robert's page so you can see what I'm talking about.
http://www.therealbobroberts.net/pots.html

But he may have come up with the various types just to make ordering easier. Hope all that makes sense.
 
it looks like he doesnt have the f-type in 500 ohms. i would go with a d-type 500 ohms. same footprint but prob a little deeper because the wheel is a knob instead.
 
The D style pot would be the perfect choice, but its more or less reversed to the way it should be. If I used one of those, the adjustment would be pointed towards the heat sink and probably very difficult to adjust. A D type or G type would both fit the footprint, but the only G-type he has is the little blue one with the screw driver adjustment. It would work, but this board mounts pretty high in the back box, and knowing my luck, when I reached up to adjust it, my screwdriver would slip and blow up the power supply or a CPU board. Still hoping to find a better replacement.
 
i believe that you can mount any way you want. So just flip the d-type around. resistors are not directional so it should not matter if it was flipped around.
 
Supposedly, a tech friend has found me one. One thing he said he discovered was although the manual calls for a 1 watt 500 ohm trim pot, you can't find any pot that has a 1 watt rating that actually fits the packaging. So the pot is actually more like 1/2 or 1/4 watt.
 
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