Saturday, August 13, 2005

 

There's Meaning To The Madness

Today the manual and schematics finally arrived at my friends place in Boston, US. He will scan them and e-mail me the crucial parts so I have something to work with. First thing I got was the reset sequence which is:
  1. Credit unit reset coil is energized by switch on reset relay, thru score motor index cam switch A, credit button, zero switch on credit unit, and switch on game-over relay or coin unit last position break switch.

  2. End-of-stroke switch on credit unit reset coil will energize coin relay.

  3. Switches on coin relay will run score motor, trip game-over relay, and energize reset relay.

  4. Switches on reset relay will open circuits to playfield switches and outhole relay, run score motor, energize reset coils on coin unit-ball count unit-player unit and game-over relay, pulse no. 1, no. 2 and no. 3 reset relays, and reset left & right bonus units to zero.

  5. Switches on no. 1, no. 2 and no. 3 reset relays, will pulse the (20) scoring drum units until they reach zero.

  6. When reset delay drops out, outhole relay is energized thru zero switch on left bonus unit, switch on alternator relay, outhole switch, delay relay and index cam switch ‘C’

  7. Switches on outhole relay will run score motor, pulse both bonus unit S.U. Coils, and pulse ball release coil to propel ball toward plunger.
I got some inspiering answers to my previous post about the matter (thanks Norm, Billg and Grojohn), so today I went to work with new glow.

First, i unplugged everything from the main board (backbox, coin door, playfield, power-switch and chimes). Then powered up and manually tripped the Reset Relay. What happened was:
So far so good, this should indicate that the problem is not with the main board, right? It also fits with the reset sequence from the manual. I also tried tripping the coin relay, which is one step before the reset relay in the sequence, and same thing happenes.

Then I connected the playfield. Still everything fits with the sequence in the manual, bonus steppers are reset and the motor stops by itself, BUT, one thing that doesn' happen is the point where the reset relay de-energizes and the outhole relay is energized, causing a new ball to be pushed to the plunger (6) Tripping the outhole relay manually does exactly as the manual says (7), so somewhere between the reset relay de-energizing, and the outhole relay firering there is an error.

I will name this "The Outhole Problem" for now :) Maybe this happens because the backbox is not connected? I'm not to sure where the "switch on alternator relay" is. Is it on the Altenator Unit (main board), or on the Alternating Relay (playfield)? And the "outhole switch"? All I can see is an Outhole Relay. I guess the " index cam switch ‘C’." is on the score motor, but it's hard to tell where as I don't have the manual pages for that part yet.

Anyways, I momentarily gave up after checking the obvious stuff, and connect the backbox. Now I got the old problem with the reset relays firering in the backbox, causing all score wheels to 000000, but no motor stop. So, the old problem, "Score Reels From Hell", is probably in the back box? I try to force the reset relay to de-energize and that stops the motor, but also leaves a wheel coil in the back box energized.

I will try to clean every single one of those darn score wheels tomorrow and see if that makes any difference. But one thing puzzles me. One of the reset switches on each and every score wheel is always "connected", or, at least it beeps when I put my multimeter to it. This is the top switch in the picture below. Is this correct? This is also present on the Alternator Unit on the main board, which switches a switch on and of with every fire of the coil. Though the switch beeps in both positions. A short somewhere, or expected behavior?



Thanks to anyone who bothered to read this far! If you have any idea why all of this is happening, please let me know with a comment! :)

RGP post here

Comments:
Hi,
I recently acquired this Grand prix game. I haven't been able to get the 4th player to work. 1,2,&3 work fine with the 4th not being able to activate.
Any ideas?

tduffy1770@comcast.net
 
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