Hi,
a friend just got a bunch of these Italian origin displays, that have a 7 digit glass mounted on a 6 digit board, with an add-on presumably to handle the additional digit.
Does anyone have info on these? Do they work with the usual 7-digit ROMs, and if so, what changes need to be done to the wiring harness between CPU and display?
7dig_addon (resized).jpgHas your friend traced the extra circuit and how it's wired to the PCB?
That should answer some of the questions.
Like the factory, a lot of dealers were caught with large stocks of 6-digit panels when the changeover to 7-digits occurred. The mod shown is very similar to how the new 7-digit display was prototyped . Molding the board from 6 to 7 is not difficult for an experienced tech. It only requires a few spare parts and a tiny circuit board as shown. I would rather just move the working glass to an original 7-digit board but these days if you want to keep the game running with PG panels you do what you can.
Trying to make some sense of the connections.
Is it so that looking at the front, rightmost pin on 6-digit glass is pin 2 (as labelled on PCB), but on 7-digit glass it is pin 1? The 6-digit board has a 7-digit glass installed and some foils at J2 cut open.
Quoted from Tuukka:Is it so that looking at the front, rightmost pin on 6-digit glass is pin 2 (as labelled on PCB), but on 7-digit glass it is pin 1?
Yes it's been a while since I looked but I did notice a pin number mismatch between the PCB and schematic when trying to repair some displays a few years ago.
You made me pull out a 6-digit Bally display (AS-2518-21 ~ same as yours pictured above) and I just noticed errors in the PCB silkscreen overlay that has caused components to be installed in the wrong positions!
The schematic amendments below show how the boards are actually incorrectly wired. There must be hundreds of thousands of boards with these errors!
There is a wire jumper next to resistor R25. R25 should be where the jumper is and the jumper should be where R25 is.
Same situation with R23 and the jumper next to it.
Thanks! I have been trying to resolve the add-on board connections by comparing schematics of 6-digit Dolly Parton and 7-digit Flash Gordon. Looks like the add-on board just duplicates the digit drivers for the 7th digit, making the modified board compatible with a 7-digit display. Needs some verification still.
Quoted from Tuukka:Looks like the add-on board just duplicates the digit drivers for the 7th digit, making the modified board compatible with a 7-digit display. Needs some verification still.
make sense. The only difference with the connector between the 6digit and the 7digit display is the additional 'D7' signal on Pin12.
So I would assume that the additional circuit is connected to pin12 and just adds the missing driver for the 7'digit.
I understand why these existed back in the day but for today in most cases, it’s a lot easier to change the roms to the divide by 10 hack… (unless they don’t exist for the game where you want to use them). “7 digit numeric” glass is really expensive now too. Or, just use a 7-digit led solution.
All of the Bally 6 digit games can be updated to the /10.
https://www.pinball4you.ch/okaegi/pro_soft.html
Any Stern games that would be requested that don't have it already (Trident and Hot Hand def. have it although I don't know if they ever made it into the wild) can be easily updated to do so.
The way the games are written make it [relatively] easy to update. They all add score by loading the X register with the value to be added, so 10 points is 0010, 100 points is 0100, 1000 is 1000. So /10 just shifts these values over. For games that actually add 10k at a time they often do it by adding it 1k at a time 10 times in a loop (and usually use the 'extra' chime to do it). This is because of replay level checking occurring at the 1k levels only.
The match has to be adjusted as well, but that's also relatively easy.
If anyone wants early stern games modded to /10 LMK.
Quoted from slochar:Any Stern games that would be requested that don't have it already (Trident and Hot Hand def. have it although I don't know if they ever made it into the wild) can be easily updated to do so.
The Trident update I released makes /10 redundant. I have a Hot Hand and it'll get the same treatment but that's probably some time off.
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