I am repairing a Williams Taxi.
The last thing I need to fix is the display showing wroung "things".
The top main display is working perfectly.
However the bottom display is acting strangely.
The regular text is showing correctly in this display, but the jackpot value and the status display behind the backglass is also showing in the bottom display.
It does not show as regular numbers (a-b-c-d-e-f-g segments), but as the center segments (h-j-k-m-n-p-r).
The regular text is simply written over the other lit segments.
The status display shows the correct information all the time.
The jackpot value during game over and the bonus value during play.
You can see the segments change in the bottom display as the value changes in the status display.

Things I've done are:
On the cpu board I replaced the segment decoder U44 (74154) due to minor battery damage.
Checked the connections and cleared the (minor) battery damage.
Also replaced the PIA at U41 and U42 trying to see if these were the problem (they weren't the problem).
I've used a display from Jokerz, but it shows the same result.

Here is an image and a video too.

Taxi_1 (resized).jpg

The extra chip and connector on the display board I am aware of.
That should not be a problem when testing with an other display board.
The main problem is the jackpot and bonus text coming thru on the bottom display.

Do you have more information about the changes needed to make on the display board?
I do have an original Police Force board, but it looks the same as the board I'm testing with.
Only J4 is used for the extra 7-digit display.
Just to be clear, the Taxi and Police Force display boards are the same type (D-12232-2)

After comparing the boards I found a difference between the D-12232-1 and D-12232-2 boards.
The D-12232-1 has resistors R53 thru R68 all mounted.
The D-12232-2 has resistors R54, R56, R57, R60, R62, R64, R65, R67 removed.
I am going to remove those resistors and post my findings here.

Yes, I was correct in my assumptions.
The removal of the resistors makes the lower display a numeric display.
The removed resistor signals are indeed used for the extra display.
All is working correct now after removing these resistors.
One jumper is added for the comma in the jackpot display.
The other jumper is added to ty the two center (g' & m') segments together for the lower main display.

Just to be clear, this information goes for using a D-12232-1 display in Taxi or Police Force needing a D-12232-2 display.

Thank you #DumbAss for helping me.

D-12232-1_1 (resized).jpg

D-12232-1_2 (resized).jpg

D-12232-1_3 (resized).jpg

D-12232-2_1 (resized).jpg

D-12232-2_2 (resized).jpg

D-12232-2_3 (resized).jpg

A former owner wanted to replace the display, but did not complete the correct changes.
He did add the J4 connector and the U3, resistors R10, 11, 12, 13, 15, 16, 17, 18.
The resistors R54, 56, 57, 60, 62, 64, 65, 67 were forgotten to remove, leaving me to search for the correct answer.

I've added this information to www.pinwiki.com
https://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#System_11B_.28Taxi_and_Police_Force.29

There I found that you could also use a display board from Riverboat Gambler.
This would be a D-12232-3 with all the parts added to support two external displays.