WEAK VUK FIX - Copied from the world wide web
The vertical up kicker (V.U.K.) used on Haunted House that kicks the ball from the lower playfield back to the main playfield tends to be weak and unreliable. To correct this problem, it is advisable to install a (modified) pop bumper driver board to give good reliable action. A weak upkicker can be a major problem with Haunted House, and much less of a problem with Black Hole. On Black Hole, if the playfield mounted 2N5879 transistors were modified with the 4.7k pull up resistors (as described above), this modification is not needed. But I would highly recommend this modification for a Haunted House!
The correct coil for the Upkicker on Black Hole and Haunted House is coil number A-4893 (535 turns of 22 gauge wire). This is mis-printed in some manuals.
There are several reasons the up kicker gets weak on Haunted House. One reason is because the normally open tungsten switch will pit with use. This pitting will cause resistance, and make the up kicker coil it connects thru weaker. Also if this switch is mis-adjusted, the coil can easily lock on and burn. I've seen this switch get RED hot while trying to kick the ball to the upper playfield unsuccessfully.
Another problem is that the four ounce steel pinball lands right on top of the up kicker's coil sleeve before it is launched vertically to the main playfield. This can cause the coil sleeve to break and/or mushroom. This causes the coil plunger to have resistance, and not operate at full strength.
Installing a Pop Bumper Driver board to replace the relay driven switch (and the coil relay that drives it) will solve the first problem mentioned. The CPU board will send a pulse to the Pop Bumper Driver board, which in turns connects the solenoid to ground for the proper amount of time. Coil burns are avoided because if the ball sensing switch gets stuck, the Pop Bumper Driver board only sends one pulse to the up kicker coil.
The next two points apply to the Haunted House upkicker, regardless if the upkicker modification is done or not.
Check where the upkicker plunger hits the ball when it's resting in the upkicker lower playfield hole. To do this, turn the game off. Put the ball in the lower playfield's upkicker hole. Manually move the upkicker plunger up, and notice where it hits the ball. It should hit it dead center. If not, adjust the upkicker mounting bracket from under the playfield till it hits the center of the ball. If the plunger hits the ball off-center, the ball will bounce off the sides of the clear plastic upkicker tube, and may not make the main playfield reliably.
Always replace the upkicker coil sleeve with a new, double flanged nylon coil sleeve. The top edge of this coil sleeve can get easily damaged from the pinball hitting it. This can cause resistance for the coil plunger.
Adjust the clear plastic upkicker ball tube. This tube must be perfectly over the upkicker ball hole in the lower playfield. If it's off-center, the ball will bounce off the sides of the tube on the way up, and may not make the main playfield reliably. Also sometimes when lowering the main playfield the tube gets mis-aligned and bends out of position. Keep an eye on this tube as lowering the main playfield! Notice the metal bracket on the lower playfield behind the upkicker ball hole. It has a half circle cut-out, and elongated screw holes for adjustment. The clear plastic upkicker ball tube should rest against this bracket in the half circle cut-out. This is done with a spring that is connected to the clear plastic upkicker ball tube.
The bracket is adjustable; if the ball is not making it to the main playfield reliably, try moving this bracket a bit. This will change the centering of the clear plastic upkicker ball tube. Also make sure the clear plastic upkicker ball tube's spring is in place with decent tension.
If one has done the above three points, and the upkicker is still not working reliably, do the following upkicker modification. This modification for Haunted House will connect the ball kicker solenoid ground lead (non-banded solenoid diode lead) to pin 1 of the pop bumper driver board. Pin 4 is connected to the normally open relay switch of the ball kicker relay coil. Pin 2 is connected to the solenoid ground. Pin 5 is connected to +5, pin 6 is connected to logic ground.
Haunted House Upgrade Parts Needed:
(1) Pop Bumper Driver Board. If an original Gottlieb board is not available, buy a new "Tom Callahan" from Pinball Resource or Pinball Lizard's upgraded pop bumper driver board from www.pbliz.com (http://www.pbliz.com/id26.htm). Both have the same pinout, and are plug and play.
(1) 6 pin female .156" Molex connector housing (for the above).
(5) Connector pins for above, Molex part number 08-52-0072 (same pins used for single sided connectors, described earlier).
(1) 4.7mfd 10v electrolytic capacitor.
(1) Male round .093" molex pin, Molex part number 02-09-2118 (optional, but recommended).
(1) Female round .093" molex pin, Molex part number 02-09-1119 (optional, but recommended).
(1) Radio Shacks' .093" pin extractor tool, part number 274-223 (optional, but good to have).
(1) Double flanged coil sleeve.
(1) A-4893 Gottlieb coil (if needed).
Procedure:
Install the Gottlieb A-4893 coil with a new double flanged coil sleeve. In a pinch, use a Williams 22-550 coil, but it won't fit real well in the existing Gottlieb coil frame. Make sure there is a diode on the coil leads with the band side of the diode going to the power lead.
If not already done, modify your Gottlieb Pop Bumper Driver board as explained previously in the section titled Pop Bumper Driver Board Fix (file:///C:/Users/Jeff/Documents/pinrepair/PinballHQ.com/sys80/index2.htm#popbump) (this reverses the polarity of capacitor C3, replaces diode CR1 with a jumper wire, and replaces capacitor C4, among other things). This modification is not required if you are installing a new "Tom Callahan" or Pinball Lizard pop bumper driver board.
On the solder side of the Pop Bumper Driver board, install the 4.7mfd 10v capacitor. Solder the minus (-) leg of the cap to pin 4 of the molex connector pin (the "input" line). Solder the positive (+) leg of the cap to pin 5 (the +5 volt line). This is a very important step! Without this filter cap, the input line running from the CPU to this new Pop Bumper Driver board can pick up noise. Every time the flippers are pressed, the upkicker can fire without this cap. Here are the pin numbers in reference to the "key" pin (the missing pin that would normally be pin 3): 6 5 4 key 2 1. This capacitor is not required if installing a new "Tom Callahan" or Pinball Lizard pop bumper driver board.
The Added 4.7mfd electrolytic capacitor on the Pop Bumper Driver Board.
Install the new Pop Bumper Driver board underneath the lower playfield. Mount it next to the relay coil that drives the upkicker coil.
On the lower playfield, remove the white-orange-blue wire from the switch on the upkicker relay coil. Remove the remaining wire connected to the other lead of this switch (and that connects to the fuse for the upkicker coil). Connect these two wires together. The switch should now have no wires connected to it. This provides power to the coil.
Note the orientation of the 6 pin molex plug on the Pop Bumper Driver board. Here are the pin numbers in reference to the "key" pin (the missing pin that would normally be pin 3): 6 5 4 key 2 1. Note pin 6 is closest to the capacitor just above the power transistor.
Remove the white-black-brown wire from the lower playfield relay coil (non-banded diode side).
Connect this wire to pin 4 of the Pop Bumper Driver board. This is the "trigger" wire for the PBDB. Before this modification, the driver board completed this wire to ground to energize the relay (which in turn energized the upkicker). Now the driver board will ground this wire, triggering the PBDB. Often this wire will need to be lengthened, depending on where the PBDB was mounted. Note the relay coil will now have only one lead with wires going to it.
Remove the two green ground wires connected to the lower playfield upkicker coil (non-banded diode side). These two wires must stay connected together. Splice two more 6 inch wires into these ground wires. Now the original two ground wires which are connected together, are connected to the two new wires. Connect these two new wires to pins 2 and 6 (ground) of the Pop Bumper Driver board.
Connect pin 1 of the Pop Bumper Driver board to the non-banded diode side of the upkicker coil. Note the two green wires were removed from this terminal in the previous step. This completes the path to ground for the coil, when the PBDB is triggered.
Connect pin 5 of the Pop Bumper Driver board to +5 vdc. To do this, route a wire along the wiring harness and to the bottom of the main playfield. Splice into pin 5 of an existing Pop Bumper Driver board located there. Optionally, to do this step cleanly, use the empty pin on plugs A9-P2/J2. Install male (#02-09-1118) and female (#02-09-1119) round .093" molex pins into the empty holes in plugs A9-P2 and A9-J2. This way the lower playfield can be easily unplugged and removed.
Summary of the Pop Bumper Driver board Pinout.
Pin 1: Switched Ground (goes to device being driven by the PBDB, to complete the device's circuit to ground)
Pin 2: Ground
Pin 3: KEY (not used)
Pin 4: Switch input (this pin gets grounded to turn the PBDB on)
Pin 5: +5 volts
Pin 6: Ground