What's new
By:
Pinball info

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Solenoids not firing on Bally Harlem Globetrotters

K

kamalackarie

Site Supporter
Joined
Jun 1, 2023
Messages
71
Location
London
Evening All

Do while trying to fix an issue with my sound card- i managed to mess up the Solenoids. What i did was pull one of the connectors from "I think " the lamp board or maybe it was the MPU - was a month back - anyways i did this with power on to the machine - which i have since discovered is not a good thing to do.

-All Voltages on the Board are correct
-when i test between the common and any given soienoid i get 5vDC - so power is getting through
-on a self test only 2( knocker) 11( coin door lock out) and 12 (K1 relay- flipper enable) work
- the fuse under the playfield is good

to make matters worse whilst trying to solve this issue it was suggested i replace U4 on the Board, which i did. in the process i lost the pad on pin4. on close inspection looking to see what to jumper to, there are no traces connecting to pin 4 - so its not used??
The schematic suggests otherwise i atatch a screen shot. U4P4 - PB2 to U2P21C some is this correct also while i am here what is "PB2" dont know the annotation and how can a chip have a pin which uses letters - i apologise fpor may idocy on y part ahead of this. U4 is in the top left hand corner on the Schematic

The solenoids not firing happened before i replaced U4

hope someone can make sense of the abve
 

Attachments

Are you getting +43V DC to the coils under the playfield? - measure from coil lug to any ground point e.g. the earth braid in the bottom of the cab.
 
AlanJ said:
What you are seeing as U4 top left of the schematic IS NOT U4 it is J4 !!!!!
Click to expand...
Dear God - i am such an idiot i never even questioned it. I just took it as part of the overall bad print on the LHS of the Schematic - time for an eye test perhaps.

So now. that thats cleared up I checked voltages on R1 to R4. They all have around 5V either side except R2 that has 5v one side and 0v the other. I will swap it out and see what happens
 
Depending on what the MPU is doing - you could well see the other side of any of R1-R4 low. that's how to MPU selects a solenoid to fire! So I wouldn't bother changing R2

Let's look at this in a bit more detail:
1. You have said the playfield solenoids are not working.
2. You have said that the only 3 coils that fire in a solenoid self-test are the 3 that are not on the playfield (coin lockout, knocker and flipper enable relay).
The fact that these 3 work tells me that the SDB board is probably working ok and is correctly interpreting signals to correctly fire the 3 solenoids.
3. Do the playfield flippers work when you start a game? If not then I suspect you have no 43V going to the playfield. if they do work then I suspect you have 43v to the playfield, but not to the solenoids.
The only difference between the flippers and the other playfield solenoids, is that the fuse on the underside of the playfield. Double check it is ok. Also check the fuse holder is making good contact (Ive had that issue several times on games).
Also check the 43v wiring is all present - has a wire dropped off a coil somewhere????

The sure fire way to test if you have power to the solenoids is to measure the Positive lug (the lug with the banded side of the diode) and ensure 43v is present at that coil lug.
As mentioned above - test the DC voltage from a coil lug to a ground point in the game.

Another test you can do is momentarily ground the metal tab of each of the power transistors on the SDB, that should fire the coil connected to the transistor.
It is very unlikely you have blown all the circuits to the playfield coils. If grounding their transistors doesn't fire any of the playfield coils, then again I would suspect the fuse or the 43v supply wiring.
 
AlanJ said:
Are you getting +43V DC to the coils under the playfield? - measure from coil lug to any ground point e.g. the earth braid in the bottom of the cab.
Click to expand...
Hey Alan, No, I am getting 5V DC to the coils under the playfield - tested both slingshots and the 3 bumpers
 
AlanJ said:
Depending on what the MPU is doing - you could well see the other side of any of R1-R4 low. that's how to MPU selects a solenoid to fire! So I wouldn't bother changing R2

Let's look at this in a bit more detail:
1. You have said the playfield solenoids are not working.
2. You have said that the only 3 coils that fire in a solenoid self-test are the 3 that are not on the playfield (coin lockout, knocker and flipper enable relay).
The fact that these 3 work tells me that the SDB board is probably working ok and is correctly interpreting signals to correctly fire the 3 solenoids.
3. Do the playfield flippers work when you start a game? If not then I suspect you have no 43V going to the playfield. if they do work then I suspect you have 43v to the playfield, but not to the solenoids.
The only difference between the flippers and the other playfield solenoids, is that the fuse on the underside of the playfield. Double check it is ok. Also check the fuse holder is making good contact (Ive had that issue several times on games).
Also check the 43v wiring is all present - has a wire dropped off a coil somewhere????

The sure fire way to test if you have power to the solenoids is to measure the Positive lug (the lug with the banded side of the diode) and ensure 43v is present at that coil lug.
As mentioned above - test the DC voltage from a coil lug to a ground point in the game.

Another test you can do is momentarily ground the metal tab of each of the power transistors on the SDB, that should fire the coil connected to the transistor.
It is very unlikely you have blown all the circuits to the playfield coils. If grounding their transistors doesn't fire any of the playfield coils, then again I would suspect the fuse or the 43v supply wiring.
Click to expand...
Hey Alan - Problem solved thanks to you pointing me in the right directon.

I grounded the transistors and got nothing ( bar the solenoid in the door).
I went back and looked at the 43v supply out of the power board - J1-6 supplies the 43v to the solenoid bus. Pulled the connector out and checked 6 and it was loose - gave it a wiggle and BOOM i have solenoids - i will re crimp it now.

do you fancy tackling a sound issue?
 
You must log in or register to reply here.
Back
Top Bottom