Need picture of a Midway 80-904b power supply board

wolfeel

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Need picture of a Midway 80-904b power supply board

Could someone post a picture of a Midway 80-904b power supply board? I think my board is missing a part and I can't find a schematic.
 
What game is it in? Usually the PS schematics are in the game manual...
 
The game is Tornado Baseball. All that it shows on the schematics are the pin numbers/wire colors and corresponding inputs and outputs. The reason I am asking is I am trying to troubleshoot the game. I am not getting the +15V from the PWR supply to the game board. Checked continuity from board to PWR supply and all ok. When I look at the board the trace from the wire leads to nowhere. See attached pics.
 

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Well, all I can find is a layout of the 904D. Apparently they didn't feel the need to document it until that version...
 
IIRC, that game uses the same supply as Space Invaders (and all the many other "L-shaped" boardsets). The 15VDC line is used for audio....it won't effect game boot up, but you won't have any sound.

Got a complete picture of that supply....I'll know for sure if it's the same as Space Invaders (etc.)?

Edward
 
Here is a complete picture of the board I have. still looking to verify that it is not missing parts. I am thinking it is not but Looking at the traces on the back I am not sure where the 15V is coming from!???!
 

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OK, that's the early version that came in Sea Wolf and Gun Fight. The only difference in that one and the later version is the adjustment pots. Early version only has a 5VDC adjustment pot.....the later version added two more adjustment pots ( for 12VDC and -5VDC).

That voltage is unregulated....so it might not be exactly 15VDC. AC voltage leaves the transformer on the bottom of the cabinet. That juice enters the power supply board and goes through 4 diodes to become DC voltage. It then goes through another diode and a 1000uf cap. At that point, it leaves the power supply board and heads to the motherboard.

Check for DC voltage across the 1000uf cap. Black lead to negative side of cap, red lead to positive side of cap. If no voltage there...back track through the diodes.

Also, (I'm looking at Space Invaders schematics) there's a fuse on the AC line after it leaves the transformer. Make sure it's not blown.



Edward
 
Oh yeah, I forgot....It doesn't look like your board is missing any parts. I don't think that pin is where the 15VDC leaves. Follow the positive side of the 1000uf cap...that will be where the 15VDC exits.

Edward
 
Check for DC voltage across the 1000uf cap and got 19.14VDC. Followed the trace and it goes to a White/orange wire that goes to the logic board at pin 11 which the diagram says is "LED V."
 

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I am trying to diagnose a dead game and just trying to verify all the voltages are correct. All I get is white screen, when I coin up I get nothing. All fuses good, +12, +5V and -5V all good. I get zero volts at the blue wire. I then traced it back to the power supply board and found that it goes nowhere. Just dead ends.
 
If it's any help, attached a schematic I redid of the 80-904 P/S used in Sea Wolf. As stated previous, it does not look as though any parts are missing from the board.

The connector picture you posted, is the plug shot straight as it is connected to the P/S? The red lead on pin 1 is different than the one here.
 

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I got a picture from smpoponi who is selling a Tornado board set and has a power supply board as well. The boards look the same!??! I guess that the game does not use that blue wire. The picture angelcare included shows that the 15V is "16V option". Perhaps it is not used. Thanks everyone!
 

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I am trying to diagnose a dead game and just trying to verify all the voltages are correct. All I get is white screen, when I coin up I get nothing. All fuses good, +12, +5V and -5V all good. I get zero volts at the blue wire. I then traced it back to the power supply board and found that it goes nowhere. Just dead ends.

It sounds to me like your power supply is fine. I have no idea what LED V stands for.....but I can tell you that voltage is for the audio.

Edward
 
I don't have any pictures of a power supply with a 15v but you do see it as an option on some of the schematics like the one posted above by angelcare. Looks like it's a 10mf 25v cap, zener diode BZX61c16 , and a 220 ohm resistor. I used your image to guess where they went. That being said it doesn't sound like you really need it after all.
 

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It sounds to me like your power supply is fine. I have no idea what LED V stands for.....but I can tell you that voltage is for the audio.

Edward

Actually in this case the "led v" supplies power for the inferred LEDs in the opto-isolators. It looks like the sound board takes power directly off the transformer (16.5v) and rectifies it on the board.
 
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