(Topic ID: 238492)

Game goes dark! Almost...

By nworker

2 years ago


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  • 18 posts
  • 3 Pinsiders participating
  • Latest reply 2 years ago by nworker
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#1 2 years ago

I'm working on a MSF and the game hung up after a ball and did not respond to the ball launch switch. I powered the game off and on and now only the mode lights in the center of the field are on with a couple of other playfield lights.

I checked all the fuses including the main fuse above the powerswitch and found f9 on the PPB (5A slo) to be blown. I replaced the fuse and no change. I'm stumped. It is like the whole game is not getting power, but these lights are on and there is AC power inside the game. The game has a pinsound card and a pin2dmd installed.

All suggestions are welcome. I have to run out so I'll be responding to suggestions later today.

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#2 2 years ago

Your outlane kicker may have a cracked diode on it that allowed a back EMF spike to take out some other part of the system. Hopefully, not the CPU board - I don't see any LED activity lamps on the upper right corner of the CPU board in your picture operating.

You should get a DMM/Voltmeter and first check all your major power supply voltages. Check for +5VDC out of the power supply at the power supply connector in the pic below.

F1= 7a slo-blo for +5 vdc (regulator input 9 vac).
F2= 7a slo-blo for +5 vdc (regulator input 9 vac).
F3= Not present on most games.
F4= 8a slo-blo for 18 vdc switched illumination.
F5= 4a slo-blo for 32 vdc low-voltage solenoids, bumpers, slingshots.
F6= 5a slo-blo for 32 vdc for L/R Relay coils and flas

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#3 2 years ago

@wayout440 Thank you for the response. I checked the voltages on the PS board. The +12 and -12 checked out, but the +5 is in the mV range. I checked the voltages at CN5 and they are dead. Where does the 5 VDC at the test point come from?

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#4 2 years ago
Quoted from nworker:

@wayout440 Thank you for the response. I checked the voltages on the PS board. The +12 and -12 checked out, but the +5 is in the mV range. I checked the voltages at CN5 and they are dead. Where does the 5 VDC at the test point come from?
[quoted image][quoted image]

Check for 19VAC coming into bridge rectifier DB1 (you can get this across fuses F1 and F2 with meter set to AC, while checking those fuse clips and fuses) the rectified DC out of the bridge runs through the 5VDC regulator circuit that feeds the test point and the connector CN5. The test point itself is not shown on the schematics. Common failures are fuses, filter caps, bridge, TR5, and IC1.

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#5 2 years ago

@wayout440 Great. The schematic I found does show the test points.

I checked across F1 and F2 and got 10.74 VDC

I checked the headers of CN6x15

1: gnd
2: -13.8
3: 13.8
4: 175 mv
5: key
6: 13.8
7: 175 mV
8: 175 mV

How might I determine which component along the 5 VDC chain is FUBAR?

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#6 2 years ago

Whoops!, yes the test points are there, I accidentally cut them off on the right when I screenshot the schematics.

Quoted from nworker:

I checked across F1 and F2 and got 10.74 VDC

Hmmmm, that's not correct. You shouldn't have any DC there. Set the meter to AC setting. You should have around 19-20 volts AC. If you don't have that coming into the board, you won't get your +5VDC logic power so we'd be working our way backwards upstream. If you have the 19-20VAC coming in then proceed to the following:

At the edge of the board by the giant heatsink for the regulator transistor, you should see wire attachment points for the regulator transistor labeled E, B and C.

Set meter to DC, and measure from ground to "C". Should see about 11VDC there. If it isn't, then set the meter to AC and take the same measurement. You should see around 40mV or less. If you are measuring much higher - in AC volts instead of millivolts, then one or more filter caps are probably bad. If the DC voltage is not present, probably the bridge. I would then remove the board and take some rectifier measurements or cap measurements to confirm, since you really have to get to the back of the board to do this. Also, would check for cracked through-hole solder joints on the back.

The regulator transistor wire labeled "B" should be around 6.77VDC, the point E would be your pre-conditioned logic voltage - about 5.4VDC. You can use standard transistor testing with the game power off to check the transistor.

#7 2 years ago

gosh, you are right, I had the F1, F2 written down as 10.74 VAC on my notes. Guess there is a problem between the keyboard and chair...

I'll check the other points.

#8 2 years ago

@wayout440 Ground to:
C is 13.64 VDC
B is 152 mV
E is 87.7 mV

I took out the board to test the transistor. With the meter set to diode

Black to C Red to E .402
Black to E Red to C 1.02
Black to B Red to E 1.02
Black to E Red to B .562

#9 2 years ago
Quoted from nworker:

@wayout440 Ground to:
C is 13.64 VDC
B is 152 mV
E is 87.7 mV

These measurements show input voltage to transistor, no output. Transistor is suspect.

Quoted from nworker:

I took out the board to test the transistor. With the meter set to diode

Black to E Red to B .562

On an NPN transistor like this you should see "0" or over limit for this measurement. This also points to the transistor as being faulty.

#10 2 years ago

@wayout440 Looking at the schematic, that makes sense as the Collector has input voltage and virtually nothing on the output which feeds the 5VDC test point. I'll see about getting a new transistor.

The one on the board is labeled 2N6056 and the schematic shows 2N6057 which supports a higher collector current. Should I go for the 2N6057, if I can find it?

#11 2 years ago
Quoted from nworker:

Should I go for the 2N6057, if I can find it?

Yes, should be 2N6057. You shouldn't have any problem finding them. Marco and Action Pinball have them in stock.

#12 2 years ago

I ordered the 2N6057 from Action and it arrived in short order. After taking the transistor out, no soldering required, and getting the new one in the correct orientation, I reinstalled the board. No luck.

I decided to replace the board with NEW REPLACEMENT POWER SUPPLY, 520-5047-03 at K's Arcade.

https://ksarcade.net/new-replacement-power-supply-520-5047-03.html

The board arrived, I installed it, and Bingo, it works! I wish I had gotten the old board to work, but it would seem the next part is was to replace the MC1723C voltage regulator. I don't have any in my pile of parts so it is back to shipping and waiting...

#13 2 years ago
Quoted from nworker:

The board arrived, I installed it, and Bingo, it works! I wish I had gotten the old board to work, but it would seem the next part is was to replace the MC1723C voltage regulator. I don't have any in my pile of parts so it is back to shipping and waiting...

Happens. Sometimes multiple failures. You've got good reliable power to play now, with a little luck you might get the old board working, possibly to save it as a backup.

#14 2 years ago

@wayout440 Thank you for all your help. Yup sometimes it just isn't going to work. I'm really glad there are updated boards available. This game has been an absolute PIA. The display, then the sound, now the PS. I've never had such bad luck.

It is a beautiful game so it is worth the effort. And next time I get an order together, I plan on ordering the MC1723 to give it a try. There is always something to having a spare

#15 2 years ago

now for the big question. does the head turn? if so you are so lucky to have an operational one. very fun game.

#16 2 years ago

wugly Yep the head turns! The game is in great shape save all the board problems. It certainly is great the generic game parts are in the secondary market.

#17 2 years ago

waiting for pintastic so I can buy some mods for mine. going for plasma bumpers and color dmd.

#18 2 years ago

Yeah those plasma bumpers look nice, but $400 is a lot of cheese

I finished shopping out the game and it looks fabulous. With Pinsound and the color DMD it is pretty special.

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