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(Topic ID: 243504)

Dr. Who WPC no 5v power issue


By jag8511

1 year ago



Topic Stats

  • 29 posts
  • 10 Pinsiders participating
  • Latest reply 1 year ago by PinballManiac40
  • Topic is favorited by 2 Pinsiders

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#1 1 year ago

I was able to get a good deal on a Dr. Who pinball machine last weekend and couldn’t pass it up. Brought it home and the only issue it had, other than needing a good shop job, is that the left upper flipper was working when the game was going. It would fire in test mode but not during the game. Sometimes however, it would randomly start working (not sure what triggered it to work) and then would work as long as I didn’t power the machine off.

Then a couple days later I was playing and noticed that the captive ball popper would sometimes have issues not firing right away. I thought it might be a sensor that was going out or it wasn’t recognizing that the ball was there so the coil didn’t fire. All of a sudden the game turned on and then off. I immediately shut off the power. It turns out the plunger rod got stuck and wasn’t operating as it should because the spring was too weak. This game had been sitting for a couple years from what the guy said. I tried turning the game back on and there was only the topper lights and some random lights in the DMD that came back on.

I checked all the fuses and they checked fine. I noticed that the CPU lights were not on and I tested the 5v test point and got .19. Tested the 12v and got 12.03. Tested the 20v and couldn’t get a stable reading. If I moved my MM probe around on the test point it would give me random numbers between 8 and 19.

I’m new to pinball and trying to learn and understand the electronics side of things. Any advice would be helpful!

#2 1 year ago

Reseat all the ribbon cables, make sure no alkaline ( battery) leakage has occured. Did you pull the fuses out and check them.?

#3 1 year ago

Try re-seating J101 if you're not getting +5V at the +5V test point.

I'm sure Pinballmaniac40 will be here to help shortly.

#4 1 year ago

Unfortunately. None of that helped. Yes - I took the fuses out. I tested them both in the machine and out of the machine.

#5 1 year ago

You’ve got a shirt somewhere. Test points ok? Make sure the flipper has the appropriate voltage, and start checking wires

#6 1 year ago
Quoted from Rdoyle1978:

You’ve got a shirt somewhere. Test points ok? Make sure the flipper has the appropriate voltage, and start checking wires

Not sure what you mean by “test points ok?” I tested them and noted that in my original post.

Forgive me if I don’t fully understand. Where do I start for checking wires? I checked all the connections on the boards but didn’t notice anything suspicious. What wires specifically should I check? What am I checking for exactly? No burnt connectors or loose connections.

#7 1 year ago

If this is anything like other WPC games I've had this sounds like typical 5v power supply issues. Here is a whole troubleshooting guide. Mostly my issues always related to the bridge rectifiers and the capacitors. http://pinwiki.com/wiki/index.php?title=Williams_WPC#Game_resets

#8 1 year ago

Test BR2. Make sure the leads are continuous with the AC input and the diodes inside the bridge rectifier test good. That doesn't necessarily mean they're good but if they test bad then you have a place to start.

#9 1 year ago

The 20V is unregulated so it will jump All over the place- it should be around 20V though

The 5v sounds like your
Biggest issue. Try reseating the Ribbon cable between the MPU and the power board. That can get corroded and stop sending signals consistently

Doctor who needs a REALLY stable power situation because of the mini playfield. You may also consider changing out the 5v power regulator to a P5US which is a life saver and does not get hot at all

#10 1 year ago

I tried to reseat all the connection on all the boards. Same result. I’ll look over the wiki guide and try to work my way through what I understand. I’ll make sure and post the results.

Is it possible that the best solution is to just send the boards in to get serviced since they are old anyway?

#11 1 year ago
Quoted from jag8511:

Is it possible that the best solution is to just send the boards in to get serviced since they are old anyway?

I don't think I would, unless you narrow the problem down to one of them that you can't fix.

LTG : )

#12 1 year ago
Quoted from DumbAss:

Test BR2. Make sure the leads are continuous with the AC input and the diodes inside the bridge rectifier test good. That doesn't necessarily mean they're good but if they test bad then you have a place to start.

Very good place to start if the driver board 5v test point is basically zero volts.

#13 1 year ago

I was able to follow the wiki guide on testing BR2. I got a 8.01 V reading. Which according to the wiki page, it should be 9 or slightly above. Could this be my problem then? I will add that it looks like it has been replace before.

I will read more of the wiki and what to test. A lot of good information there but definitely appreciate the input.

#14 1 year ago

Unfortunately the wiki guide is more about when the game is resetting. So I’m not sure where to go from here. I took the board out to check for cold solder and couldn’t find any. It should be noted that BR2 and C5 looked to have been replaced at some point already. Any ideas on where to go from here to get the 5v power back?
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#15 1 year ago
Quoted from jag8511:

Any ideas on where to go from here to get the 5v power back?

Since C5 was messed with, you may have lost through board continuity on it's legs.

LTG : )

#16 1 year ago
Quoted from LTG:

Since C5 was messed with, you may have lost through board continuity on it's legs.
LTG : )

ltg How would I got about testing or fixing that?

#17 1 year ago
Quoted from jag8511:

How would I got about testing or fixing that?

The capacitor sits on top of things that need checking.

I'd remove it. Put a stitch in each hole. Put on a new capacitor.

LTG : )

#18 1 year ago

What needs to be “stitched”? It looks pretty clean.

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#19 1 year ago
Quoted from jag8511:

It looks pretty clean.

That side looks good. The other side looks good.

The damage may be in the channel/hole between the two. Can you see that ?

When the board is made, there is plating in that hole from one side to the other. When people remove components, especially capacitors. This through hole plating/continuity can be damaged.

I'd take a small bare wire. Run it through the hole, bend over on each side and solder to the pad each side. Then stick the capacitor in and solder it in place.

When the capacitor is flat to the board, it's impossible to check continuity from each leg to both sides of the board, away from the repair area.

LTG : )

#20 1 year ago

ltg I put in the stitches and now I got 4.77 v on the 5v test point and the 5v LED turns on! Making progress. I do also get the 5v light on the CPU but that is it. No GI / no game boot / random dots on DMD. Seems like I don't have a stable enough 5v for everything to work?
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#21 1 year ago

Any ideas on what to check to bring the 5volts back up to 5 volts?

#22 1 year ago

Your stitch may not be enough. I would be adding wire to another point on the paths for + and -

#23 1 year ago

BR2 to C5: two jumpers. Jumper the positive lead of bridge BR2 to the positive lead of C5. Repeat for the negative leads also.

BR1: ONE jumper. Jumper the AC lead of BR1 (just below the positive lead) to connector J101 pin 7.

C6/C7: jumper the two positive leads of capacitors C6 and C7 together (this also jumpers also helps BR1).

BR3: three jumpers. Jumper the lower AC lead of BR3 (just below the positive lead) to connector J104 pin 1. Jumper the other upper AC lead (to the left of the positive lead) to connector J104 pin 2. Jumper the positive lead of BR3 to the large solenoid fuse trace about 2" below the bridge (see picture below).

BR4: three jumpers: Jumper the negative lead of BR4 to the negative lead of C11. Jumper the AC lead of BR4 (just above the negative lead) to connector J102 pin 1. Jumper the other lower AC lead of BR4 (just below the positive lead) to connector J104 pin 4.

BR5 to C30: two jumpers: Jumper the positive lead of BR5 to the positive lead of C30. Repeat for the negative leads also.

#24 1 year ago

chad I was trying each jumper that you suggested, step by step and then testing the board. I got down to the BR3 jumpers and turned on the machine to test and saw a spark. Running the jumpers from the AC leads on BR3 to pin 1 and 2 on J104 is the last jumpers I tried. I tested BR3 and it tested ok. I took all the jumpers off BR3

2 months later
#25 1 year ago

Did you get this fixed up?

-3
#26 1 year ago

Maybe rob kahr’s daughter board for wpc Will help with the load on the 5v supply.

1 month later
#27 1 year ago

I took the machine to a local who works on pins and he reseated ALL ribbon cables and that fixed the issue. I did try kahr's daughter board but that didn't do the trick. Game runs great with or without the daughterboard now.

#28 1 year ago
Quoted from jag8511:

I took the machine to a local who works on pins and he reseated ALL ribbon cables and that fixed the issue. I did try kahr's daughter board but that didn't do the trick. Game runs great with or without the daughterboard now.

Ribbon cables don't carry the 5v. I am guessing he reseated all the cables, which most likely means your j101 plug needs the male pins and female connectors rebuilt.

#29 1 year ago
Quoted from dsuperbee:

Ribbon cables don't carry the 5v. I am guessing he reseated all the cables, which most likely means your j101 plug needs the male pins and female connectors rebuilt.

and or J114

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