Very strange WPC 95 flipper problem

Discussion:

(too old to reply)

Ron Kral

2021-04-15 00:31:47 UTC

I've got a Junkyard which was working perfectly last week.
Installed a color DMD. Now the flippers don't work
(likely not related to Color DMD installation IMHO).

1) ALL Switches register in diagnostic switch test including
door, both flipper buttons and flipper EOS.

2) ALL coils work in diagnostic mode (except flippers).

3) ALL flipper fuses are good

4) 74V at ALL flipper terminals

5) Both Flippers DO operate if alligator clip grounded from their respective
ground tabs to the side rail (both Strong and Hold, both left and right).

SO, CPU "sees" flipper buttons, all circuits are working....
CPU apparently is not grounding the coils to fire them???

What am I missing here???

Ron Kral
CARGPB #23

John Robertson

2021-04-15 03:00:29 UTC

Permalink

Post by Ron Kral
I've got a Junkyard which was working perfectly last week.
Installed a color DMD. Now the flippers don't work
(likely not related to Color DMD installation IMHO).
1) ALL Switches register in diagnostic switch test including
door, both flipper buttons and flipper EOS.
2) ALL coils work in diagnostic mode (except flippers).
3) ALL flipper fuses are good
4) 74V at ALL flipper terminals
5) Both Flippers DO operate if alligator clip grounded from their respective
ground tabs to the side rail (both Strong and Hold, both left and right).
SO, CPU "sees" flipper buttons, all circuits are working....
CPU apparently is not grounding the coils to fire them???
What am I missing here???
Ron Kral
CARGPB #23

What power source does the colour DMD use? If it is one of the game's
supplies, then unplug the new and put the old DMD back and see if the
problem goes away...

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Lloyd Olson

2021-04-15 17:18:49 UTC

Permalink

Post by John Robertson

What power source does the colour DMD use? If it is one of the game's
supplies, then unplug the new and put the old DMD back and see if the
problem goes away...
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

John is right. Easy test. Unplug the color DMD, and play a game blind. If it works, get a separate power source for the color DMD.
LTG : )

Ron Kral

2021-04-16 19:39:52 UTC

Permalink

Post by Lloyd Olson

Post by John Robertson

John is right. Easy test. Unplug the color DMD, and play a game blind. If it works, get a separate power source for the color DMD.
LTG : )

This was a good suggestion to remove the new Color DMD from the equation.

Sadly, it didn't work - even with the new color DMD disconnected, the flippers still don't work.
This just seems almost impossible. As I noted before, ALL flipper buttons register as working in
diagnostic mode, AND I can "manually" cause the flippers to work by shorting the flipper
tabs to ground. It's like the CPU "sees" the flipper button, and "tries" to close the circuit,
but something is preventing that from happening. Buttons work. Flippers work. All other
coils work. What's in the flipper circuit that's not in the other coil circuits?

John Robertson

2021-04-16 20:17:52 UTC

Permalink

Post by Ron Kral

Post by Lloyd Olson

Post by John Robertson

What power source does the colour DMD use? If it is one of the game's
supplies, then unplug the new and put the old DMD back and see if the
problem goes away...
John :-#)#

John is right. Easy test. Unplug the color DMD, and play a game blind. If it works, get a separate power source for the color DMD.
LTG : )

This was a good suggestion to remove the new Color DMD from the equation.
Sadly, it didn't work - even with the new color DMD disconnected, the flippers still don't work.
This just seems almost impossible. As I noted before, ALL flipper buttons register as working in
diagnostic mode, AND I can "manually" cause the flippers to work by shorting the flipper
tabs to ground. It's like the CPU "sees" the flipper button, and "tries" to close the circuit,
but something is preventing that from happening. Buttons work. Flippers work. All other
coils work. What's in the flipper circuit that's not in the other coil circuits?

OK, you have power at the flipper coil lugs, did you check that you have
the flipper power at the driver transistors on the Fliptronic Board? You
need to have the 74V at the tabs of the respective driver transistors -
Power (Q90 & Q87) and Hold (Q92 & Q89) for each coil.

If you have power at the transistor tabs, does its respective flipper
coil fire when you ground the corresponding tab? Remember that the hold
coil will barely move the flipper - if at all, so lift the flipper bat
and check that the coil starts tugging about 1/2 way up...

Hope this helps!

John :-#)#

LexingtonVAPin

2021-04-17 21:31:27 UTC

Permalink

Ron, have you checked the ribbon cables? There is a ribbon cable that
goes from the CPU to the Fliptronics 2 board, then to the audio board
and onto the DMD board. Any chance you jostled that ribbon cable? It
connects to J903. If you are off a column at any one of those boards,
it could mess things up, but you likely would lose sound and display, too.

The flipper buttons and EOS come into the Fliptronics board and through
that ribbon cable to the CPU. Since the CPU 'sees' those buttons, the
ribbon cable connection is likely good.

Since you have power to the coils, the power supply is OK. The coil
power is generated on the Fliptronics 2 board and connects to the AC via
the power driver board. Since you get power to the coils, that
connection is likely fine.

But it still gets +5 V and +12 V from the Power Driver board via J904.
That is likely OK, since I doubt the circuitry would detect the flipper
and EOS switches via the CPU without those voltages.

The coils get the power from J907 so that is good. But activation
occurs via J902, so look at that one.

Next to check would be U2 with a digital probe, I would think.

--
http://orcalcoast.com/

Ron Kral

2021-05-04 14:09:58 UTC

Permalink

Ron, have you checked the ribbon cables? There is a ribbon cable that
goes from the CPU to the Fliptronics 2 board, then to the audio board
and onto the DMD board. Any chance you jostled that ribbon cable? It
connects to J903. If you are off a column at any one of those boards,
it could mess things up, but you likely would lose sound and display, too.
The flipper buttons and EOS come into the Fliptronics board and through
that ribbon cable to the CPU. Since the CPU 'sees' those buttons, the
ribbon cable connection is likely good.
Since you have power to the coils, the power supply is OK. The coil
power is generated on the Fliptronics 2 board and connects to the AC via
the power driver board. Since you get power to the coils, that
connection is likely fine.
But it still gets +5 V and +12 V from the Power Driver board via J904.
That is likely OK, since I doubt the circuitry would detect the flipper
and EOS switches via the CPU without those voltages.
The coils get the power from J907 so that is good. But activation
occurs via J902, so look at that one.
Next to check would be U2 with a digital probe, I would think.
--
http://orcalcoast.com/

Just to bring closure to this...
I pulled the MPU board to install a remote battery holder...
While out, I carefully straightened all the pins (they really
didn't seem to need it, but just in case)...
Upon re-installation, the flippers magically started working
again.. Not sure just where the bad connection was (I had
already tried removing and resetting all the MPU plugs)
but there you go. It's working now and I ain't touching it!
THANK YOU ALL FOR YOUR HELP AND SUGGESTIONS.
Ron Kral