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FIXED - Party Zone - WPC Fliptronics help - Rows shorted

Andy B

Andy B

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1 10 Years
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Oct 6, 2014
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Location
Hull. England.
Probably a dumb question but - Party Zone:

Machine boots up but won't start a game.

After testing is complete (head rotates to right as you look at it but then does not rotate back around) comes up with message "Grnd. Short Row 1 is stuck closed".

Test report shows:

"Grnd. Short Row 1"
"Grnd. Short Row 3"
"Grnd. Short Row 4"
"Head Malfunction Use Head Test"

I followed Pinball Repair Guide instructions on how to test the switch rows (attached clip to J207 pin 1 then used other end (with diode attached) to touch J209 pins 1 to 9 in turn).

Each time I touch a J209 pin I am getting a message that the corresponding switch row has a Grnd. Short.

My questions is, does this mean that the chips are gone (LM339 at U18 and U19) (I suspect it does since as there are so many rows shorted) or something in the wiring to the playfield - I'll be honest, I don't really understand the comment in the guide "If a particular row does not display as closed or is closed without any test lead connection...".

Couple of other things which might be relevant I guess:

  1. Coin door interlock switch has been removed (wires to it were just hanging loose so I twisted them together so it acts like the switch is there and closed)
  2. Not storing anything in memory despite new batteries installed - keeps factory resetting every time switched on (old batteries had started to rust but no leakage to speak of).

Thanks in advance for any guidance...and no laughing please :)

Andy
 
Further update:

Pinball Repair Guide Section "Switch Matrix Short: Is It The CPU Board or The Playfield" advises you to "Remove all four switch matrix playfield plugs. If error goes away there is a playfield short.". So I entered test mode (you have to do this before removing all 4 connectors obviously since as one of them connects the coin door switches!), switch levels, disconnected plugs. No error. Replaced one plug at a time. Got error messages. So this means playfield shorts right? But is on two different plugs so multiple shorts - isn't that weird?
 
So presumably that also means a diode(a) has probably gone on one of the switches allowing the power to go down the switch lines?
 
Hello, Andy,

I think Party Zone is a bit early to have a power interlock/safety switch on the front door, just the matrixed switch (2,2) showing the Cpu that the door's closed. If the wires are connected together, it's no problem switching wise, but I doubt you'd be able to get into the bookkeeping or test routines. I nobbled a Funhouse once, where the location had a key (and were prone to tampering with the settings), by wiring another switch in parallel so they simply got the display "Open Door to use buttons". Leaving it 'Open' is no problem for most early wpc games

If the previous battery had rusted, is the holder still any good? I've seen some where contacts had fallen out, causing an open circuit in the battery pack

It's quite likely that the problem is the Column driver chip, as Pick Holder says, despite the messages about Row short circuits. It seems to serve a sacrificial role regarding the switch matrix and solenoid power. See another recent thread about the subject from 'parisno' about "Terminator 2 Gnd Short"
 
Thanks both. Couple of new chips ordered.

Am I right that I will still need to do some downstream diagnostics to see what fried the chip?

Will fit remote battery holder I think.
 
You do have a door switch - its the 'memory' switch.

PZ does not have a switch that turns off the higher voltages to playfield.

A lot of people change GI lamps with the game on. If a holder touches a switch then it will blow out the uln2803a.

Todd at TNT calls it the fuse chip because it stops serious damage to the rest of the board.

In most cases, these are socketed - if it is not - then I would recommend that be done :)
 
Pick Holder said:
You do have a door switch - its the 'memory' switch.

PZ does not have a switch that turns off the higher voltages to playfield.

A lot of people change GI lamps with the game on. If a holder touches a switch then it will blow out the uln2803a.

Todd at TNT calls it the fuse chip because it stops serious damage to the rest of the board.

In most cases, these are socketed - if it is not - then I would recommend that be done :)
Click to expand...
Luckily it’s socketed so couple of new ones ordered (the 339s are not socketed though so hope it’s not them that are buggered!).
 
Update 21-12-2020:

Replaced the uln 2803a chip on cpu board (cheers Pick Holder!) and that solved all the switch grounding errors. Only error in test report after that was date and time not set.

Took an emery board to the battery holder contacts and that sorted the memory issues. I soldered some wires to the battery holder terminals ready to fit a remote battery holder (ordered). I set the date and time and set it to freeplay.

I played a few games.

Then I switched it off and moved on to the GI - there were quite a few bulbs out - that turned out to be a blown fuse. So I replaced that.

Tried to start a new game but start button not working. Checked fuses again and F115 (12v switch matrix) needed replacing. Done that.

Start button still not working.

Tried all the usual:

Checked all fuses
Checked ball trough switches
Checked switches in same column and same row (in fact checked every switch and start is the only one not working)
Checked micro switch was working properly (even swapped it out for a new one because the old one was ugly :-))
Checked continuity in wiring - the wiring goes from the switch to an under playfield PCB and then to the backbox board. Continuity from switch to under playfield board. Continuity from under playfield board to back-box board. No continuity from the two under playfield board connectors where the wires from switch come in and go out but diode in between so that's correct right?
(Briefly) touched the switch wires together
Reflowed solder on pins on under playfield board

Absolutely nothing doing.

I am totally out of ideas. Surely it can't be that uln 2803a chip again? If that was fried then I would have whole rows/columns out again, not this one individual switch right?
 
If you’ve seen previous posts by me you’ll know that’s not a silly question Chris 😊

Yep - setting to free play was first thing I did after setting date and time.

If I press the service credit button on inside of door it says Freeplay too.

Start button blinking away also.
 
And now it's not working again!

I noticed the old microswitch did not have a diode on so when I swapped it out I didn't put a diode on the new one but then, once I got it working again, I thought "Don't all switches have to have a diode and maybe the lack of a diode was what messed it up last time so I'd better fit one."

So searched it up as to which way the diode needed to be soldered on and also checked start button on my Elvis Presley. Connected as such:

Green/Brown wire to N/O
White/Orange wire to N/C
Unbanded end of diode to N/C (with white/orange wire)
Banded end of diode to COM

Nothing's happening again.

Connected up a new microswitch without a diode

Green/Brown to N/O
White/Orange to N/C

Nada.

Then I also remembered that the thing would not start when I briefly touched the two wires together so it can't have been me wiring the button up wrong.

Now I am totally stumped!
 
It no use looking at a Stern to see how the PZ button should be wired.

Go into switch test (using the 4 door switches)

You could have a duff start button. Or also check the PCB in the left of the coin door - the IDC connections can work loose. This playfield has the diode on it for the start switch.....

Better still - I will give you £800 for it :) (the Party Zone not the start button) :)
 
Hah :)

Not mine mate - someone has been crazy enough to let me try and fix it for them!

The Start button light has also gone now - swapped the bulb out and still dead.
 
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