If you say the displays are good, try replacing U20 (CD4502).
That is the chip which selects which display to show the data at the appropriate time.
It's only a 50 cent part....

Check the 43V fuse.
Or the J4 connector on the MPU.
To board may just be missing the 43V to boot.

You said you did repinning...
Also A4J1?
Check for a short between J1-10 and J1-11.
Otherwise I'm out of ideas...
Maybe Quench can help.

Have you tried unplugging all of the displays and then plug one in at a time.

Can you please try this for me:
Disconnect connectors J2 and J3 from the MPU board - these are playfield and cabinet switch harnesses respectively.
Disconnect connector J4 from the lamp driver board.

Do P1 and P2 displays still mirror the credit/match display?

The game switches and lamps share the same signals with the display select signals so disconnecting those connectors I mentioned isolates them from the display circuits.

see if any of the latch strobes are shorted together. can do some resistance comparisons from the working MPU to the one acting up. If the latch strobe is happening at the wrong time the displays will read/display data intended for a different display.

Untitled (resized).png

try swapping the U10/U11 PIA chips that drive the displays to see if the problem follows a PIA chip

Pk98 Good day! Did you ever get the display mirroring resolved? I have the same on my flash gordon. I did what Quench said above (2 connectors off MPU and J4 off lamp boar) and problem persisted for me. I have not replace U20 but was going to.

Which displays are showing as mirrored on your game?

Quench Howdy! Credit and player 3 share data and player 1 and 3 share score (see pics). First one is before a game start, second is in a game trying to show the duplicative scoring.
Looks like there is shifting also, like positions are off

pasted_image (resized).pngpasted_image (resized).png

What happens when you swap the player 3 with player 4 display? Does the problem follow the display or stay as it was?

Quench when I switch 3 and 4 it stays the same. Part of credit is on player 3 and it mirrors the score of player 1 but off by one digit on player 3. I know I need to go through the displays and fix digits out and normal refurb. Does the fact it did not move point to the MPU (U20 or some other IC)?

Hmm, there are no other issues with the game? Lamps all lighting when they should and switches operating correctly?
Got another Bally MPU board to hookup temporarily? - no need to change ROMs just plug it in and disconnect J4 from the solenoid driver board so solenoids don't incorrectly activate.

Otherwise grab your multi-meter and set it to resistance mode. If it's not an auto-ranging meter put it on the 200k ohms resistance scale. With one meter probe on pin 2 of MPU U20 and the other meter probe on the third displays pin 1 of the U1 chip you should measure around 20k ohms. If horribly out you have a connection problem on that display select signal. If it's in resistance range then try swapping U20 on the MPU board.

Thank you @quench! I got no reading so will work on connection, check headers for cold joints and refurb the displays. Then I can retest and see if I need do U20. Will go ahead and order one just in case.

The credit / ball in play display is the last written to in the display refresh sequence.
An open circuit on the 3rd display select signal could result in that display accepting all data written to any displays and since the credit / ball in play is last, those details will stick the most.

First thing simply wiggle the J1 connector on the MPU board and the display connector to see if it's a connection issue on either end.

Quench Well I retested all my U20 connections to all 4 displays (J1 pins 20 to 24) + credit and got 20k on each respective pin (from display U1 pin 1 back to U20 respective pins). Parts came in from Marco so I swapped out U20. No real change. Then I replaced the U11 PIA. No real change.

I consider the digits
7, 6, 5, 4, 3, 2, 1 when you look at the display

So Initial start:
P1= 7 to 3 on ones and 00 on digits 7 and 6
P2=0 on 6 digit and 00 on ones and tens
Credit shows 300 (digits 6, 5, 4) and 0 on ones
P3=300 on hundreds/tens/ones
P4=shows 4 0 in thousands, hundreds, tens, ones

When it switches to high score:
P1: flashes all digits and you can see the high score something like 105600 but hard to make out with the flicker
P2: flickers all but the 6th digit when showing 105600
Credit=shows 5600 starting from the digit 6, 5, 4, 3 digit 2 off and digit one =1
P3:flashes all digits and you can see the high score something like 105600 but hard to make out with the flicker
P4:flashes all digits and you can see the high score something like 105600 but hard to make out with the flicker

Start a game:
P1=00 and scores
P2=1 in digit 6
Credit= looks correct digit 6 and 5 show 38 and ones = 1
P3= starting from hundreds it shows 38. Will mirror the scoring from P1 for thousands and hundreds on P3 digit 6 and 5
P4 blank

In test:
P1= cycles correctly except tens and ones dont always show, it flickers but counts correctly when you can see it
P2=cycles correctly
Credit=cycles correctly
P3=cycles correctly
P4cycles correctly

In a game after first few switches it keeps scoring (P1 and P3 displays) then stops. I checked all the switches up there and they seem good. If I put it in switch test and leave it there for a while or bang on the playfield I dont get any switch errors (with ball out). Not sure if that is related to displays or not.

Where do you think I should go from here? Could U8 be bad and screw up the info sent to displays?
pasted_image (resized).png

U8 is a possibility, *especially* if someones installed a Chinese counterfeit part in the last few years. Can you post a real clear picture of it so I can see if it's real or not?

Quench Here is the pic. Good news it is socketed and I believe I have some 5101's in my Bally box. Can swap it and see tonight.

pasted_image (resized).png

pasted_image (resized).png

Ami Brand 6810... That Brand has a higher failure rate than others.

Success!!!!!! Changed the 5101 and the display issue is resolved as is then weird scoring issue. Quench thank you so much for your guidance! I learned so much more about the Bally displays through this.

IMG_5317 (resized).jpeg

Great!
Your 5101 is an original "Synertek 5101L-3". Can you do me a favor and post a picture of the back of the chip?

A few year back when good Philips 5101 were cheap and plentiful from China I bought 100pcs. To my horror I received remarked chips of various unknown brands. The worst part was the very high failure rate and from memory did see various display issues with some.
A rear picture of yours may help me brand cross reference some of these remarks.

Anyhow great to see you fixed it

here are a few from my chip graveyard.

20231129_204224 (resized).jpg

20231129_204312 (resized).jpg

Thanks!

Below is a sample of the junk 5101 remarks I got - doesn't look like yours match any:
The very bottom picture is real Philips chips which is what I was expecting.

PCD5101P_Fakes.jpg

Real Philips PCD5101P chips:

PCD5101P_Real.jpg

Some more.

20231129_232439 (resized).jpg

20231129_232649 (resized).jpg

That's a fair collection!

I used to fix a lot of bally and WMS MPU boards. Dead 5101s was pretty common. I've got a nice 6810 collection too as I would always convert 6808s to 6802s in the sake of one less socket.

So many different brands back in the late 70s to early 80s.

Quench Here is mine...

pasted_image (resized).png

Thanks fellas, the original marks on the bottom of my remarks don't seem to match any in these pictures. Oh well.

I've found a few too....

5101_chips.jpg

I've found a few more that may interest you....

5101_chips_2.jpg

5101_chips_3.jpg

Quench after fixing the displays the max credits no longer registers (when I set the dips to max 40). Both dip 25 and 26 are clearly on and none of the components in line test messed up. from one side of 25 and 26 to the other it measures connected.

Also the single drop target will still do run away scoring but not everytime. Picture A was how it was wired which looked wrong to me so I changed it to picture B. Either way I still get run away scoring from time to time on that switch.

Trying to understand the single drop....Game start, press the shooter lane switch (close to the shooter rod), first 3 shooter lane rollovers dont score, once you get past them the single drop target comes up and the the 3 shooter lane rollovers score. Is that normal? Then does the single drop target increase in value or is it 10000 each time you hit it?

pasted_image (resized).png

all those switches under the playfield are wired the same.

just look at the next switch in the daisy chain.

i believe pic B has the diode with correct orientation but i can't make out how the wires are soldered to the leaf blades.

also the blades don't look like they are correctly aligned/set up.

do the 3 non scoring rollover switches show in switch test?

Rikoshay yes the switches work in test. I think it is a “feature” of the game but didn’t see anything written about it. Will work on the blades and the drop mech

Cheers, where did you buy the remarked Philips 5101?

What is max credits registering up to?

Picture A looks right to me based on what I can see of the leafs in the stack.
These games are designed to ignore closed stuck switches to prevent runaway scoring. You more likely have a switch gapped too closely that's touching with playfield vibration.

Looks normal to me.

Playfield says that drop target is 10,000 points and doesn't say it increases.

Is there a flag in the fg code to prevent duplicate scoring? Maybe the switch is dirty/bouncing causing multiple activations.

A quick check in PinMAME says there's no 'down flag' for that drop target. So playfield vibrations can cause multiple activations due to poor switch conditions.

I do not remember buying them.
Mostly they are pulls because of the replacement with nvrams.
I think they came with a batch of parts buy.
I hardly need any 5101 chips.

Quench the max credit reads zero. The only way I get credits on there is if I manually add them. It will remember the amount I add when powered off.

Agree on the drop and rollovers working as designed. I watched Bowen's PAPA tutorial and seems to work that way (even though I could not see scoreboard). The rollovers score in switch test and the whole collect bonus thing works in the shooter lane.

I did clean that single drop switch and found with the gap. It is much better. All the switches on this one are gunky and wonky gaps so will be a process but at least it is playable now.

I think you're misunderstanding the purpose of the max credit switches. It is the maximum allowed number of credits, not a fixed number of credits.
So if you keep pressing a coin switch you will never be able to go beyond 40 credits. i.e. the game can have anywhere between 0 and 40 credits as you've set them.
The stock factory ROMs do not have any freeplay mode via the max credit switches. However many modified ROMs provide freeplay when both of those dip switches are on.

Operators liked setting those max credit switches to 5 or 10 limiting the number of backup replays players could get.

Quench I guess I was expecting it to act like my Eight Ball did. When I set those 2 dips then every time I turned it on I got 40 credits (effectively freeplay up to 40). I guess it had freeplay set roms on it. So if there is a ROM dependency on FG too then I need to update the ROM.

On a Strikes and Spares I did the replay set really low (like 6k) to add credits but that causes the knocker to go off....so was not as slick a solution.

If you have access to an EPROM programmer, there are freeplay ROMs out there for Flash Gordon and Strikes and Spares.

Quench I do, so I got the VPFforum U6 freeplay one which worked for freeplay but dip settings for 31 and 32 were either 2 ball or 4 ball. 3 and 5 ball will not work no matter the combo.

Then I tried pinball4you's process to create a custom U6 with Freeplay but it is not working. I guess I can be happy with freeplay and 4 ball til I figure out a better ROM for U6.