Well, I thought it would be cool to own a tabletop pinball machine, and I was wrong.
I bought it as working, but has intermittent sound and needs a display.
So firstly, the "working" part :-
You can coin it up and start a game, all coils, lamps and flashes seem to work fine.
If you press the flipper button firmly then it works fine, as soon as you tap a flipper button quickly (like when you get a little spark on the flipper button) then the game resets
1) Disconnected the reset board - still the same
2) Replaced the diodes on the flipper coils - still the same
3) Cut all ground connectors off the transformer frame and directly mounted all the ground wires to the transformer frame through the bolt holes - still the same
4) Replace the bridge rectifier and filter capacitors for the 12v (to 5v) circuit - still the same
5) Added direct ground wires soldered onto every board and then attached to the ground strap - still the same
6) Removed the ROM daughtercard and re-soldered it all, replaced all the pins and re-soldered to the CPU board. Replaced all the sockets with new turned pin sockets - still the same
7) Re-flowed everything on the 5v power supply, put new pins on and replaced the pot with a fixed value resistor - still the same
8) Soldered wires from the +5v out of the power supply and soldered them onto both the CPU board and driver board - still the same
9) Added additional filter capacitors directly on the CPU and driver boards where the +5v sources are - still the same
10) Cleaned up all the edge connectors and re-pinned all the important connectors - still the same
Nothing has made any difference at all. What next?
So the soundboard was not intermittent - it was dead. I put it on the test bench and managed to repair it so that I could manually trigger the sounds by grounding the data lines, and that seemed to be fully working.
Put the sound board in the cab and the LED does not flash, it just either stays on or off and you get static sounds.
Put the sound board back on the bench and it it working fine.
Back in the cab still nothing.
Checked all the sound board voltages as fine.
Put the CPU board back on the bench and tested the RIOT chips using the Leon test ROM, all outputs seemed to be fine.
Checked every IC on the driver board and checked every transistors
Then there is the displays. I have a display-board (untested - but I can see the glass is good) but I get nothing out of them at all.
Checked the voltages are fine in the game.
Checked the RIOT was working, found 2 dead 74LS175 and a dead 74LS04 next to the display connector on the CPU board and replaced them all.
Re-pinned the connectors at the display and CPU board end - still nothing out of the displays.
The next step will be to check for activity on all the datalines on the display board itself with the game running.
To make matters worse, working inside the tabletop is twice as hard as working in a normal pinball backbox, you have to really lean over the top to get in at the boards, everything is hard to get to, there is no slack in the wiring and everything is upside-down.
The system 80 design is a nightmare!
So after many hours of work, the only thing I have made any difference to is that I have a sound board that will work fine on the bench, and technically I have fixed all the crappy ground and power problems that Gotlieb are plagued with, but it didn't make any real difference.
Any ideas on the resets?
I bought it as working, but has intermittent sound and needs a display.
So firstly, the "working" part :-
You can coin it up and start a game, all coils, lamps and flashes seem to work fine.
If you press the flipper button firmly then it works fine, as soon as you tap a flipper button quickly (like when you get a little spark on the flipper button) then the game resets
1) Disconnected the reset board - still the same
2) Replaced the diodes on the flipper coils - still the same
3) Cut all ground connectors off the transformer frame and directly mounted all the ground wires to the transformer frame through the bolt holes - still the same
4) Replace the bridge rectifier and filter capacitors for the 12v (to 5v) circuit - still the same
5) Added direct ground wires soldered onto every board and then attached to the ground strap - still the same
6) Removed the ROM daughtercard and re-soldered it all, replaced all the pins and re-soldered to the CPU board. Replaced all the sockets with new turned pin sockets - still the same
7) Re-flowed everything on the 5v power supply, put new pins on and replaced the pot with a fixed value resistor - still the same
8) Soldered wires from the +5v out of the power supply and soldered them onto both the CPU board and driver board - still the same
9) Added additional filter capacitors directly on the CPU and driver boards where the +5v sources are - still the same
10) Cleaned up all the edge connectors and re-pinned all the important connectors - still the same
Nothing has made any difference at all. What next?
So the soundboard was not intermittent - it was dead. I put it on the test bench and managed to repair it so that I could manually trigger the sounds by grounding the data lines, and that seemed to be fully working.
Put the sound board in the cab and the LED does not flash, it just either stays on or off and you get static sounds.
Put the sound board back on the bench and it it working fine.
Back in the cab still nothing.
Checked all the sound board voltages as fine.
Put the CPU board back on the bench and tested the RIOT chips using the Leon test ROM, all outputs seemed to be fine.
Checked every IC on the driver board and checked every transistors
Then there is the displays. I have a display-board (untested - but I can see the glass is good) but I get nothing out of them at all.
Checked the voltages are fine in the game.
Checked the RIOT was working, found 2 dead 74LS175 and a dead 74LS04 next to the display connector on the CPU board and replaced them all.
Re-pinned the connectors at the display and CPU board end - still nothing out of the displays.
The next step will be to check for activity on all the datalines on the display board itself with the game running.
To make matters worse, working inside the tabletop is twice as hard as working in a normal pinball backbox, you have to really lean over the top to get in at the boards, everything is hard to get to, there is no slack in the wiring and everything is upside-down.
The system 80 design is a nightmare!
So after many hours of work, the only thing I have made any difference to is that I have a sound board that will work fine on the bench, and technically I have fixed all the crappy ground and power problems that Gotlieb are plagued with, but it didn't make any real difference.
Any ideas on the resets?
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