Check the LM339 on the opto board on the bottom of the pf. Swap it out with the one in your JM and test, I'm not sure they're the same though.

Edit: looks like they're different

IIRC...there are 3 of them on that board. On mine it was the left chip that was locked up.

Disconnect J212 as well, the Gun-trigger and Slam-tilt are here on row1.

Still have row1 short ?, then inspect cpu-board.

Zaza to the rescue...ur da man Z. I guess by the cpu you mean he should inspect U20 right?

No, when all matrix connectors are disconnected, U20 does not have any influence on the rows.
I'm more on U18 now or battery corrosion on traces above U18/19
Row 1 CPU89.jpg

You can perform some tests with machine powered-up if you want.

It could be powerdriverboard with problems on U7 and U8 opto-coupler. Boot the machine without the small ribbon-cable between CPU- and PDB and go into switch-test. Still GND-SHORT ROW 1 ?

And you can measure the voltages on input and output of the lm339.
remove all switch matrix ROW cables from CPU (J208, J209, J212)
power up machine and measure -> red voltages
2nd time with row 1 jumpered to GND -> blue voltages.

row1.jpg

Multimeter set to Vdc, range 20V or autorange
BLACK pen to GND, could be a screw where CPU-board is mounted.

1. RED pen to R51. Both sides of resistor should give 12Volt
2. RED pen to U18 pin13. ( "pink 1" in picture ) should give 5Volt. U13 pin11 should have same value.

attach a wire from GND to J209-1 (lower right on board) and measure same points again:
1. RED pen on R51 should give now 0.8Volt
2. RED pen to U18 pin 13 should give now 0.1 Volt

It seems that some place the signal is already LOW where it shouldn't.

That means that lm339 works as it should.

Did you measure U13-11 as well? same value as U18-13 ?
or with machine OFF there should be continuity between those 2 pins.

To be sure that data DO is ok on the cpu-board, can you do a test, for example activate lamp #1 in 'single lamp-test'.
And a continuity test from U12-8 to U13-9 (purple line)
And in switch test T.1 , verify only ROW1 is shorted.

U cpu.png

If all have continuity, data D0 is working then U13 is most likely the problem.
After these measurements and checks, a logic probe won't give more information.

Any battery corrosion that could have eaten a trace ?

you can solder a jumper from U12-8 to U13-9 and check the switch matrix in game.

A jumper will do so you can leave the chip in place.

an extra check for continuity for data-DO on other chips (purple line) to be sure and it should be ready to play.

I will check tomorrow for updates

Wait with the jumper, this is WPC-s and has different layout.

will have a look at it deeper tomorrow

edit:
for now, re-seat the security-chip U22 and test the switch matrix again.

Gathered some interesting points where you can use the logic probe.
These are pulsing data signals communicating around the security chip.

probe U.jpg

Nothing connected to the switch-matrix connectors = J209-1 HIGH, a jumper to J209-1 = LOW
5 out of 6 have a lit red+green led and only R0 has only green led lit when J209-1 is High

Maybe this gives some new information but the communication around security is very different from older WPC.

You can use C31 to hook up probe. careful not to touch other conducting traces/solder spots.
Also interesting to know is whether or not COLUMN 1 is working in the switch test. Activate any switch in column 1.

ok, only if the logic probe show different signals, it might give clues.

That is correct, one time a HIGH 12V (pull-up) and the other time a LOW (jumper GND to J209-1)

How about the R0 signal at U13-9 ( = U22-18 and U14-9 ) ? see picture post #23 magenta legs
And A0 signal at U22-10 ( = U24-18 and U23-2 ) cyan legs

If there is a problem with one of the IC's, it is difficult to determine which one is the problem because in each case 3 ic's are connected to the same data line. Possible need test software to find out.

That is always possible but you got still the "GND-SHORT" message when it was disconnected, correct ?
If GND-SHORT disappears when opto-board got disconnected, then we can stop looking at the CPU-board.

Well, I'm actually glad it is not the CPU.

since only ROW1 has a problem I would say that U1 pin13 stays LOW all the time on the 10-opto board.
You can measure with voltmeter J3 pin12 (everything connected, machine ON) and should find about 10Volt pulsing.
If it is about 0 Volt, U1 is blown.

10 opto R1.jpg

try to find out why row1 is blown. Could be a short between lamp/coil...

I think it is best to take the 10-opto-board out the machine and measure with multimeter set to 'diode'.
U1-13 and U3-14 with black pen and keep red pen on GND:

10-opto U1 U3.jpg

Both should be around 600mV

ZAZA, please accept this as a "helpful hint" - I certainly appreciate your excellent drawings and fantastic knowledge of the electronics involved and I'm sure many others do as well - that is not in doubt for a second.

We call the 'pens' as you call them, PROBES, when they are used with a meter.

I only mention it because I usually have to read your posts twice before I realise what you mean.

Keep up the good work!!!

: ) Thank you Mike,

I thought both were used to name the things at the end of the red and black leads. I'm still learning every day....and forgetting the double. From now on I will call it probes.

Wait. It's normally closed? That doesn't sound right. According to the Switch Matrix it should be open?

Shadow Matrix (resized).jpg

Do U18 pins 13,14,1,2 and U19 pins 13,14,1,2 all have the same voltage?

And do U20 pins 18,17,16,15,14,13,12,11 all have the same voltage?

ok, something is pulling U18p13 down from what's connected to the CPU-board
The 2 R1 outputs of both lm339 seem ok when powered OFF.

If you can put 12Volt (adapter) on the 10-optoboard when it is outside the machine, it is possible to test the R1 exits and see if they are 'high' or 'low'. All rows should be 'high' on J3 when only 12V power is supplied to J3-1 (GND) and J3-2 (+)

Ok so to clarify it in my head, with power off and you measurure resistance across the switch you have an open(infinite resistance) and when you press the target brick wall drop down target it measures a short(0 to a couple of ohms). Is that correct? If it is, did you replace U1 and U3 on the opto board?

Also, whenever replacing the lm339 I put a socket in. You could also see how the opto board works when you engage a different "working switch" to see how the output changes from 3v to a low.

Sorry, I can't visualize this. Can you take a pic maybe? Also, you could use another switch as a comparison such as the "battle drop down" switch? Measure that the same way as the other switch. Do they measure the same way?

Let's skip this one, the exits are floating when not active and 'low' when active. It would take a setup with pull-up resistor to check it this way.

A final check for the 10-opto board is with only J3 connected in the machine and into testmenu T.1

I think I had a similar problem to this in my shadow and it was one of transistors on the fliptronics board. I haven't read the posts in this thread so take this with a grain of salt.

7 year ache .... did you get it fixed?