(Topic ID: 252487)

No 50V WPC


By robm

1 year ago



Topic Stats

  • 9 posts
  • 5 Pinsiders participating
  • Latest reply 3 months ago by PinballManiac40
  • No one calls this topic a favorite

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#1 1 year ago

Hi All,

Picked up a WCS with no 50V. What i have done to date:

Tested (twice) fuse F112 out of circuit

Checked J102 - this is strange (but hopefully gives a hint as to the problem?) - when it is unplugged, there is 13VAC across the black/yellow wires, however when i plug this into the power driver board, it drops to 0.5VAC. This occurs, even when only J101, J102 and J104 are plugged into the board

Pulled out power driver board - it looks quite clean - replaced BR3 and C8, which as far as i can see are the only components in the 50V circuit, and still presents the same symptoms

I'm a bit stumped as to what to do now, any ideas?

#2 1 year ago

coin door switch.

#3 1 year ago
Quoted from robm:

Hi All,
Picked up a WCS with no 50V. What i have done to date:
Tested (twice) fuse F112 out of circuit
Checked J102 - this is strange (but hopefully gives a hint as to the problem?) - when it is unplugged, there is 13VAC across the black/yellow wires, however when i plug this into the power driver board, it drops to 0.5VAC. This occurs, even when only J101, J102 and J104 are plugged into the board
Pulled out power driver board - it looks quite clean - replaced BR3 and C8, which as far as i can see are the only components in the 50V circuit, and still presents the same symptoms
I'm a bit stumped as to what to do now, any ideas?

I was searching for 50v power on my driver board for a game I was working on and had nothing. The coin door had been removed and the bracket removed from the coin door so the switches were not being activated. Once I realized that, I found the bracket for my door in the coin box, reinstalled and everything works great. It may not be your exact problem, but I would double check connections at the coin door switches.

#4 1 year ago

Ha ha ha. I can't believe how stupid i am. Classic case of over thinking a problem - it was the coin door open. To give myself some of the benefit of the doubt, when i looked at the game a month ago, no coils were working (and i thought i had the door closed, but i could be wrong), so i straight away assumed a driver board problem.

Anyway, its got a nice new bridge and cap in it now!

#5 1 year ago
Quoted from robm:

Ha ha ha. I can't believe how stupid i am. Classic case of over thinking a problem - it was the coin door open. To give myself some of the benefit of the doubt, when i looked at the game a month ago, no coils were working (and i thought i had the door closed, but i could be wrong), so i straight away assumed a driver board problem.
Anyway, its got a nice new bridge and cap in it now!

A lot of the time it is the simplest thing that causes the problem. Glad you "got" it.

1 year later
#6 3 months ago

I only have 21v on my 50v test point. Swapped boards and it works, so problem is on board. Checked the AC coming in and it's fine. I see that C5 is a component I may want to replace, is there a BR3 on WPC95 boards?

#7 3 months ago
Quoted from Methos:

I only have 21v on my 50v test point. Swapped boards and it works, so problem is on board. Checked the AC coming in and it's fine. I see that C5 is a component I may want to replace, is there a BR3 on WPC95 boards?

Technically, it is better if you start a new thread. WPC95 driver boards have 4 separate diodes that essentially make up one bridge rectifier and there are quite a few diodes on the board.

Are you testing the voltage with the coin door closed? What test point are you testing at?

This should get you started. https://www.pinwiki.com/wiki/index.php?title=Williams_WPC#LEDs_and_test_points_on_WPC-95_Power.2FDriver_Boards

#8 3 months ago
Quoted from PinballManiac40:

Technically, it is better if you start a new thread. WPC95 driver boards have 4 separate diodes that essentially make up one bridge rectifier and there are quite a few diodes on the board.
Are you testing the voltage with the coin door closed? What test point are you testing at?
This should get you started. https://www.pinwiki.com/wiki/index.php?title=Williams_WPC#LEDs_and_test_points_on_WPC-95_Power.2FDriver_Boards

That is why I couldn't find a BR on that board. Coils stopped firing, then fired at reduced strength. Coin door was closed and I tested that switch.

There isn't any 50v on the board at all, it measures 21v throughout the entire line, but the AC looks to be coming in correctly. The board is out of the game now, so I was going to make the repairs.

#9 3 months ago
Quoted from Methos:

That is why I couldn't find a BR on that board. Coils stopped firing, then fired at reduced strength. Coin door was closed and I tested that switch.
There isn't any 50v on the board at all, it measures 21v throughout the entire line, but the AC looks to be coming in correctly. The board is out of the game now, so I was going to make the repairs.

Diode test the big diodes. You may have one bad, that is not shorted, but reading higher than it should. I say that because, if there was a shorted diode, it would blow a fuse. Then you would not have 50v at all.

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