Bally 5000 Plus hopper payout not working -- SOLVED

[thefixitworkshop]

Hello-
I am working on this 1989 5000+ that has all functions working except for the hopper payout.  on a win or self-test 04, the system is quiet for about 10 seconds, i hear the hopper motor twitch, on the hopper piggy-back board the LED1 (right) flashes once red and LED2 (left) illuminates amber for about 10 seconds. 32 displays in PAID window. putting a meter on the hopper motor during a self test does not show 24vdc. manually activating the coin payout switch 10 times during self test 04 satisfies system with no errors.  here's what i've done:

- regreased hopper motor gear case, cleaned behind coin wheel, and adjusted coin guides. spits out quarters fast with 24vdc applied to motor on the bench and draws about 1 amp.
- rebuilt the hopper piggy-back board with all new semi-conductors and caps, except for one IC MC74HC32AN using exact replacements.
- recapped the back plane, and 2 insert boards, cleaned edge connectors, inspected for burned traces. replaced 3.6v battery on board
- new power supply RQ-85D

all reel logic, coin comparator, lights, switches are functional.  i really thought rebuilding the hopper piggy-back board would solve my issue but we are not getting 24v to the hopper motor during payout.  ideas?

-dan

[thefixitworkshop]

since this photo, i've replaced each semiconduction except the one with the 'Inspected' sticker on it.  one thing i noticed is that looking at a photo of another AS-3356-13, they have 4 BUZ11A MOSFETs and i have 3 of them plus a TIP120 Darlington transistor. didn't look like it had been replaced by a tech in the past. might change that to a BUZ11A for the heck of it.

-dan

[Badbaud]

Is the 24V output working from the power supply?

[thefixitworkshop]

it is, just measured it at the backplane PS connector.  also changed the TIP120 Darlington for a BUZ11A MOSFET to no effect.

-dan

[thefixitworkshop]

reseated all ICs on all boards along with a dribble of DeOxit in the sockets.  no change.  just as a point of data, 24v is not present at the 8amp at any point during the 04 test.

-dan

[thefixitworkshop]

well, i finally solved the puzzle and beat this machine.  100% working now.  checking voltages on the hopper piggy back board, there was not 5v present on pins 2 and 3 of the 555 timer, U3, as shown was needed in a diagnostic flow chart.  looking at the 5000+ schematic shows that U3 is supplied a hopper forward signal from U29 on the motherboard.  this is a R6522P VIA chip and had to source one on eBay.  replaced that today and BOOM! the hopper works correctly and the entire machine is 100% functional with all lights, buttons, payout, and logic working correctly! 

-dan