Evel Knievel solenoids pull when in test mode..but not during game

Bullwinkle

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Evel Knievel solenoids pull when in test mode..but not during game

I've just put a new (to me) MPU -35 into an Evel Knievel I'm working on (originally MPU -17). The 35 was tested working as a playboy mpu prior to this use. I'm using 2732 eproms, so I did the jumpers listed on pinrepair for using 2732s:

e4 to e13a
e12 to GND
e7 to e8
e10 to e11
e31 to e32
e16a to e29
e33 to e35

I removed all other jumpers. The board itself gives the 7 flashes and then boots up with displays. I can also cycle through the lights test, display tests and solenoids test.

The problem I'm having is, during test mode, it will cycle through all solenoid tests successfully (pop bumpers pop and slingshot bumpers kick). But when I fire up a game, the pops and slingshots are dead as well as a few other items on the playfield. flippers work as do the targets and the sol that resets them. I've checked the transistors on the driver board with a DMM and they all show as good (check with power off, negative to the tab, positive to each leg, DMM in diode mode, middle giving 0 and outer legs giving approximately 5.5)

I'm pretty sure I need to do some work on the solenoid driver board's HV section as the displays tend to become garbled, followed by a hum and then a click, then they display proper digits for another minute or so and the hum/click cycle continues. Not sure if this would affect the solenoids though.

Just curious as to why they would function in test mode but not game play. Any help or suggestions are appreciated. I'll be doing all the suggested upgrades to the solenoid driver board.

Thanks,

Tom
 
maybe because the machine isnt powering other items during the solenoid test? this is an odd issue, it worked before the new MPU board? or not at all before the MPU?
 
How about switch test?

First time with a Bally, didn't realize the 4th press of the test switch brought up a switch test. Will check it out after I correct the power issues on the driver board. Thanks Ken.

Also, I have another driver board, but it's a Stern SDU-100 instead of a Bally A3 Sol Driver Board (AS-2518-16)... they look identical, are these interchangeable?
 
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First time with a Bally, didn't realize the 4th press of the test switch brought up a switch test. Will check it out after I correct the power issues on the driver board. Thanks Ken.

Also, I have another driver board, but it's a Stern SDU-100 instead of a Bally A3 Sol Driver Board (AS-2518-16)... they look identical, are these interchangeable?

Those two are interchangeable but be careful when swapping Bally and Stern regulator/driver boards because the later Bally boards had the high voltage fuse on the board but the early Bally and Stern boards didn't (it's external). That means that putting a board with no fuse on the board into a game intended to have a fuse on the board will eliminated the high voltage fuse all together (potentially not good).
 
The problem I'm having is, during test mode, it will cycle through all solenoid tests successfully (pop bumpers pop and slingshot bumpers kick). But when I fire up a game, the pops and slingshots are dead as well as a few other items on the playfield. flippers work as do the targets and the sol that resets them.

I agree with Ken. I would look at the switches first. Take a brief look at the switch matrix schematic to see if the problematic locations are on the same row or column of the matrix. If they are you know you've probably got a connector problem at the MPU or a daisy-chain wire off somewhere. I would check each switch individually in switch test and trace the problems one by one if there is no obvious problem associated with all of them.

I've checked the transistors on the driver board with a DMM and they all show as good (check with power off, negative to the tab, positive to each leg, DMM in diode mode, middle giving 0 and outer legs giving approximately 5.5)

You already know the transistors are good because the solenoids work in test mode.

I'm pretty sure I need to do some work on the solenoid driver board's HV section as the displays tend to become garbled, followed by a hum and then a click, then they display proper digits for another minute or so and the hum/click cycle continues. Not sure if this would affect the solenoids though.

That's definitely strange. I would test the displays one at a time in the same location letting each one run for maybe 10 minutes. Then put them back in their original positions one at a time and see if there is a problem with any one display or position. Bad displays can do weird things.

Just curious as to why they would function in test mode but not game play. Any help or suggestions are appreciated.

The obvious thing to check first are the switches, though that's not the only possibility. If the game is never told to energize the solenoids they won't work during game play and the switches tell the MPU to energize the solenoids. The fact that they work in test tells you that the MPU is able to control all of the solenoids. It's just not doing it when you want it to.
 
Thanks Lindsey, I appreciate the breakdown. Didn't even think about the matrix and it being a column or row issue. Will work through the switch test this evening and see what I get.
 
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