The bonus display at a Stern Lightning 1981 does not show the units, tens and hundreds.
This bonus display is placed in the playfield. Its a 6 digit, (only 5 digits from the right are visible), connected to the BTI-100 interface.
See attached schematic.
All the signals at that connector are connected to the credit display - only pin 3 comes from the solenoid board, solenoid 18.
The hundreds and thousand are used from the credit display, because they are not in use.
They work fine. Bonus counts etc... The 1, 10 and 100 must be generated somewhere.
I checked the cables conncetions 3 times, all are good. Sure because they all (except pin 3, Sol 18) go to the credit display and that works fine.
But where come the "zeros" for 1, 10 and 100 from?
example how the bonus looks like: X39000
The onehundred digit (X) is not in use, (not visible, only the right 5 ones). The other 1, 10 and 100 should be always "0"
- In diagnostics the 3 digits do not work
- Tried other displays, directly at the connector with and without the BTI-100 interface, they all do not show the 0, 10, 100.
I'm not wondering about that, because its the same like credit display and that does not show that digits. See schematic.
- I replaced Q1, then U2, nothing changed.
- Checked connector pins & cables at the solder pins, twice, all have good contact
- I checked Sol 18 Transistor and cable connection, looks good.
- I detached the connector from the credit display - nothing changed. Credit Display does not make this issue.
Now however my question is:
- what does Solenoid 18 do?
- how are the zeros at 1, 10 and 100 generated?
Then I think I can find a solution.
Nothing can be found in the internet about that bonus display or a similar issue.