Bally Strikes and Spares (Bally, 1978) Coil not firing

[Sonora70]

Just picked up my first solid state to try to fix up. All seems to be working except the right slingshot coil is not firing. I have done the following,
The machine finds the switch in test mode, operates as it should.
The coil fires when I jump from the ground wire to Q11
During the self test, the slingshot coil does not fire.


Another problem is that the #10 tone coil comes and goes. Works sometimes and doesn't other times, however points are still given when the target is hit and the tone does not work.

I'm finally getting to the point of understanding some logic on the EM schematics, however I can't follow the schematics on this solid state at all. Any help much appreciated....Thanks.

 

[Coil_Smoke]

Look for a pulse at the base of Q11 during during coil test . Maybe that transistor is toasted open.

 

[Sonora70]

Look for a pulse at the base of Q11 during during coil test . Maybe that transistor is toasted open.

Do I do this by using my ohm meter set to volts and placing the black to the ribbon and the red to Q11? Just to be sure.

 

[pinballdaveh]

it looks like the 10 point chime works off of Q1. the chime coil should fire every time you ground out Q1,s tab. since the r sling and the chime coil use different driver chips on the driver board it may not be a board problem. i would first check the MPU to sol driver board solenoid data lines. on the solenoid driver board its J4 (right side bottom connector) pins 3-7. the MPU board its J4 (left side bottom connector) pins 1-8. this female connector on the MPU is the usual problem because of battery corrosion that works it way up and into the connector. corrosion on these male and female pins can cause coils not to work , or the wrong coils to fire because of the bad connections. re-pinning of the female pins may be needed.

 

[Sonora70]

it looks like the 10 point chime works off of Q1. the chime coil should fire every time you ground out Q1,s tab. since the r sling and the chime coil use different driver chips on the driver board it may not be a board problem. i would first check the MPU to sol driver board solenoid data lines. on the solenoid driver board its J4 (right side bottom connector) pins 3-7. the MPU board its J4 (left side bottom connector) pins 1-8. this female connector on the MPU is the usual problem because of battery corrosion that works it way up and into the connector. corrosion on these male and female pins can cause coils not to work , or the wrong coils to fire because of the bad connections. re-pinning of the female pins may be needed.

Yes, the chime and the r sling both fire every time I ground them out. I checked continuity between the two connectors while one was partially plugged in...to clarify, I would stick one of my DMM leads into the female portion of one connector then to the male pin of the other board with the connector partially plugged in. I did this to both sides. I got continuity across the board. After "messing" with the connectors I did get the rsling and the chime to work, however they both quit during a game. This happened a couple times and I cannot get it to repeat. Frustrating.

One observation is that it looks as thought the transistors for both the rsling and the chime have previously been replaced. They are a different color than the others and I can tell they have been resoldered on the back of the board. I did some continuity spot checking and they seem to be connected cleanly.

The battery mentioned it a bit corroded on the sides. I'm sure that is something I need to replace as I have read that it should be done. Thanks for any other tips you can offer.

 

[pinballdaveh]

a DMM test might not be a true test in this case. an intermit. or bad female pin only might show good some of the time. you said that messing with the connectors briefly made these work. individual inspection of the female pins still should be done. solder connections under these jacks should be checked for cracks , but rarely go bad.

 

[Sonora70]

a DMM test might not be a true test in this case. an intermit. or bad female pin only might show good some of the time. you said that messing with the connectors briefly made these work. individual inspection of the female pins still should be done. solder connections under these jacks should be checked for cracks , but rarely go bad.

Well.....frustration grows. The machine is not going through a full start when I turn it on. The coils are not coming on, no tone is playing at start up to indicate the machine is ready for play.

 

[pinballdaveh]

count the MPU led flashes. it should be 1 pause then 6 more flashes to complete start up

 

[Sonora70]

count the MPU led flashes. it should be 1 pause then 6 more flashes to complete start up

That is still happening.

 

[Sonora70]

New development....after plugging/unplugging the 2 connectors on the right side of the solenoid driver board the coils activated at startup. The odd part is that I have done this multiple times with no change until now. I assume I have a connector problem? When the game booted I started a game to see the results and the rsling worked but only momentarily. The chime continued to work as it should.

 

[Sonora70]

I am still not able to get the rt slingshot to fire on this pin. I have put new connectors on the .156 headers, resoldered all .156 header pins, checked and repined the .100 connectors (J4 connectors on mpu and sol boards) and after leaving the J4 connectors on both the mpu and the solenoid boards I turned them over and did a continuity check from different points on the back of the board to the other board. All traces check out. I also checked R31 and it reads the same as R27(left slingshot). The pin is completely working now except the rt slingshot. What is my next step? Is there a chip on one of the boards that is bad? Is there a way to test them?

 

[pinballdaveh]

you can use your dmm to take resistance readinge of Q11 both forward and reverse polarity on its 3 legs and compare the readings to the transistor next to it. grounding out the tab does not check the driver transistor , it checks the wiring,jacks,coil,diode, and circuit traces back to the driver transistor. so Q11 still might be bad. parts you might want to change are Q11 , CR11 , and U3 last. check resistance values of R31,R32,and R70 , replace parts if needed.

 

[Sonora70]

results of tests......still no sling

you can use your dmm to take resistance readinge of Q11 both forward and reverse polarity on its 3 legs and compare the readings to the transistor next to it. grounding out the tab does not check the driver transistor , it checks the wiring,jacks,coil,diode, and circuit traces back to the driver transistor. so Q11 still might be bad. parts you might want to change are Q11 , CR11 , and U3 last. check resistance values of R31,R32,and R70 , replace parts if needed.

Tested the resistance of Q11, matches the transistor beside it. CR 11 tested the same as CR10, CR9, and CR8. R31 tested the same as R27, and R25. R32 tested the same as R30 and R22. R70 tested the same as R69 and R71. Not sure if U3 can be tested, however when I set my DMM to diodes and put my black lead on the ground at TP8 and measured each pin on both sides measured the same as U1. Is that a correct way to test this chip?

As a second test I took the board out of my Vector machine and put it in the Strikes and Spares and everything worked correctly so I know it must be something on this board.

One observation is that sometimes when I first turn the machine on after it has been off the coil will fire but only a couple of times. Rarely getting through a ball of play. Is there something else that needs to be inspected?

 

[pinballdaveh]

most intermit. problems are connector or connections related i would reflow the solder connections on U3 and U2 and test in machine. does the chime coil work 100% now or is it still intermit.? your U3 test seems to be correct. an in machine test of U3 a logic probe may be needed to see the pulse coming out of U2 to R70. some DMM's on a low dc volt range might not see this pulse. U2 is what the chime coil and the sling have in common. U2 is a 74154 decoder availible from marco $4.95 and a 24 pin socket should be installed to save the chip from solder heat.

 

[Sonora70]

most intermit. problems are connector or connections related i would reflow the solder connections on U3 and U2 and test in machine. does the chime coil work 100% now or is it still intermit.? your U3 test seems to be correct. an in machine test of U3 a logic probe may be needed to see the pulse coming out of U2 to R70. some DMM's on a low dc volt range might not see this pulse. U2 is what the chime coil and the sling have in common. U2 is a 74154 decoder availible from marco $4.95 and a 24 pin socket should be installed to save the chip from solder heat.

The chime coil is working 100%, I assume it was a cracked solder I found and reflowed. Not knowledgeable of the process to check for a "pulse" between U2 and R70. I will reflow the connections on U3 and U2.