(Topic ID: 97874)

TECH: NBAFB HELP! ShotClock/Defender Situation.

By PinJer

5 years ago

Topic Stats

  • 17 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by Poopiehead
  • No one calls this topic a favorite


Linked Games

#1 5 years ago

My defender and shock clock seem to be connected to one another. I had just finished a game, in which both the shot clock and defender had not moved, then for about 5 seconds both the defender was moving AND the shot clock was working in "attract" mode. It then all quit working yet again and have not had either of them budge ever since… Is this a shortage or a bad solder job on the board? Any NBA owners left out there that could help?

#2 5 years ago

I have a customer's game that we have yet to figure this out on.

WPC95 driver boards have 4 additional outputs for controlling 2 motors at connector J110. These outputs weren't present on the earlier driver boards.

This is used in NBAFB for the shot clock and defender motor. Believe they are used in MM for the drawbridge, and in MB for the drac and frank motors etc, some pins don't use these.

Tried replacing the ULN2803 chip at U3 and the 74ls374 at U4 on the driver board and this didn't fix it. About to swap the board from a TOTAN into the NBA since the TOTAN does not use any of these drives.

#3 5 years ago

PinJer - could you swap the driver board from your other NBAFB to the malfunctioning one and see if the problem is resolved?

#4 5 years ago

westofrome- i definitely would but i only have one. i just noticed it says i have two. lol i apologize. kbliznick - keep me posted my good man. its as if they both flicker randomly and quit?

#5 5 years ago

I had this exact issue - I replaced everything thinking it was this or that… It ended up being an issue on the Driver board itself. I found this out when I put a new driver board in to resolve something else.

#6 5 years ago

i thought i spotted a questionable weak solder this morning on what i think is the driver board (just to the right of the motor/swingarm?) that looked like it could use some a quick fix? Do they still make these driver boards?
I appreciate all the feedback gentleman, its good knowing the machines werent all broken down and sold for parts... lol

#7 5 years ago

I just purchased a new board from the australian parts site and it could be one of the best under $40 pinball purchase I have made in a while.... but we'll see if that will fix it.

#8 5 years ago

The driver board we are talking about is the very large one in the lower right corner inside the backbox. These are around $300+

#9 5 years ago


#10 5 years ago

Yeah - I got the other part from Australia as well did not fix the issue. If it's the driver board fixing can be done - my tech could not do it becaue it was a mail thing and he did not have the game to see if it was working or not.

#11 5 years ago

I have learned so much from this machine and it has added a couple gray hairs too, but hoping it is nothing too crazy. $309 from Australia for a board is a bit much for a clock and defender issue. Is there a specific area I should be looking at when I get home and start sifting through the board? Can I plug into the J110 extra outputs or look for a bad solder? Like I said, it worked for 5 seconds this morning and then both died on me again? I am hoping its just a loose wire or a connection issue and not a fried chip or diode. My rookie skills cant handle much more. lol

#12 5 years ago

All I can say is this was my learning game as well - I spent way to much money trying to get it working perfectly. I should have done a better job on repairing and not replacing parts. I ended up going with a new driver board when the one I had probably could have been fixed. So this is my way of saying I can't help, but i can tell you what worked for me.

#13 5 years ago

Haha I appreciate all of the great insight you shared. I thank you again. I attempted to check everything tonight, it is all good and but I noticed when I play a game, the right loop diverter hums and continues to power and stay up much longer than before. Almost to the point of annoying. You can feel the power it is over bearing but I shot the ball in a test game up at it, the power let loose and the shot clock and defender turned on! As well as the magnet.Problem was, when I was finished with in the paint mode, it all quit again...

I am becoming almost irritated at this game. It takes up way too much of my time trying to fix this problem.

#14 5 years ago

Game Clock and Defender are still not responding. The diverter under the launch ramp always is humming… Just seeing if anyone else may have a suggestion before I buy a $300 board. :/

#15 5 years ago

Some more info

Power to the motor driver board and shot clock come from the unregulated 12V circuit at J139 pin 2. This is the same power that runs to the optos in the game. Verify the connector is on there. If the optos are working odds are the 12V unregulated power is OK. Check to make sure that 12V connector is good at the motor and clock boards.

3 years later
#16 1 year ago

I’m having a similar problem. Just got the machine, and it had no power to the shot clock or defender. Reseated everything, pulled all the fuses, no change. Finally bought and installed a new rottendog driver board, and still
The same problem. (Incendentally, I guess i’ve got a working WPC 95 board for sale now). I’m not sure where else I should be looking. PinJer, did you ever fix this? Any other advice? I’m stumped.

#17 1 year ago

Just an update: we pulled out and replaced (temporarily, with a working one) all of the boards, and even the shot clock assembly itself. No luck yet.

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