Midway clowns.

[Lurch666]

Just been working on a midway clowns pcb. It's a standard 8080 invaders PCB with a clowns daughterbord with shifter,sounds and controls.

It's been a standard space invaders fix so far apart from it crashing if the dips are set for 2 coins per credit which took a while for me to notice. Putting it on one coin per credit lets the game coin up normally.

I'm now wondering if anyone has this boardset because I was having issues with the player one controls. Player two was working but the pin on the connector that handles the player one controls appears to go to a resistor then the resistor is connected to nothing.
Here's where I found the pinout:https://arcarc.xmission.com/archive/Web Archives/ionpool.net (Dec-31-2020)/arcade/pinouts/Clowns.txt



Looking at the player two connections I found it needed to be connected to pins 6/7 of the 555 timer that produced the control pulses. There is no sign of any track that might have been burned off or otherwise removed so I'm puzzled in that in it's original state it appears that the player one controls would never work.
Anyone got any insights to this. A lack of schematics for this daughterboard certainly makes things more difficult.

 

[kingtreelo]

thought this was a diss on people who worked at Midway when i saw the title in the sidebar

 

[Lurch666]

thought this was a diss on people who worked at Midway when i saw the title in the sidebar

Looks to me like some clown made a mistake on this PCB alright.
Just not sure if it isn't me.

 

[philmurr]

Just been working on a midway clowns pcb. It's a standard 8080 invaders PCB with a clowns daughterbord with shifter,sounds and controls.

It's been a standard space invaders fix so far apart from it crashing if the dips are set for 2 coins per credit which took a while for me to notice. Putting it on one coin per credit lets the game coin up normally.

I'm now wondering if anyone has this boardset because I was having issues with the player one controls. Player two was working but the pin on the connector that handles the player one controls appears to go to a resistor then the resistor is connected to nothing.
Here's where I found the pinout:https://arcarc.xmission.com/archive/Web Archives/ionpool.net (Dec-31-2020)/arcade/pinouts/Clowns.txt



Looking at the player two connections I found it needed to be connected to pins 6/7 of the 555 timer that produced the control pulses. There is no sign of any track that might have been burned off or otherwise removed so I'm puzzled in that in it's original state it appears that the player one controls would never work.
Anyone got any insights to this. A lack of schematics for this daughterboard certainly makes things more difficult.

I did a test ROM for Clowns and sure I have schematics for the daughterboard.

I'll check tomorrow and send you the info if I find it

 

[Lurch666]

Yes I found that clowns has some sort of watchdog on the daughterboard.
It passes the ram tests on the space invaders test rom but not the shifter because when I grounded to pin required to get the shifter to work that also appears to kick the watchdog in and the space invaders test rom wouldn't run.

 

[Lurch666]

@philmurr Kindly provided me with schematics which showed I was correct in my assumption that the resistor (R6) is supposed to be connected to pins 6 and 7 of the 555 at C1:


I was just taking pictures to show where the missing track was and I spotted something:

It was tricky to get a picture as my phone camera wouldn't focus properly but in the red circle you can just see a track going under the resistor and that connects to the track passing under the resistor that comes from the blue capacitor. The blue circle shows where it goes to pins 6 and 7 of the 555. There's a break along here which was causing the issue so it looks like there are no clowns at Midway.