Just donate it to papa as they need a 4th for pinburgh

I dont have a high hand but when working on the reals in the bottom I general put the PF in the most upright position (bottom slid as far back as possible) and I hold the PF in place with some rope (to keep it from falling on my head). Can be a PITA so curious how others do it.

I would remove the whole playfield and lift it out of the cab. Makes access that much easier, especially if you're working on the stepper in the back right of the cabinet.

Not sure if you've looked at the pinballninja website but Clay has a pretty nice video where he details some repairs on High Hand.

I'd start by cleaning and/or adjusting the Bonus Unit. In particular, the contacts and snow shoes that slide over them. Everything should be shiny and the snow shoes should slide easily in and out of their sleeves. The snow shoes should also land in the center of the contacts each time Bonus Unit stepper advances.

The High Hand bonus count is a terrific design. If you're really curious how it works, read on.

The bonus count starts when the ball drops into the hole or rolls over either outlane and closes a switch which fires the H/Hole relay:
High Hand Hole relay (resized).jpg
The H/Hole relay starts the Score Motor turning and holds itself active through its own holder or lock in switch (labeled H). Initially the H/Hole relay is held active until the end of the 1st Score Motor cycle when the Score Motor 2B switch opens. By then however the Bonus Unit has taken a step and the Bonus Unit Runout switch has closed to keep the H/Hole relay active until the bonus count has completed.

Just above the H/Hole relay on the schematic is the Add Bonus Unit solenoid. As we'll see in a minute, the Bonus Unit takes several steps as the bonus is being counted. The pulses for those steps come through the H relay switch in series with the Score Motor 1B and 1A switches.

So at this point the Bonus Unit is in position 0, H/Hole relay is active and the Score Motor has just started turning. To figure out how the points are added we need to look at this part of the schematic:
High Hand Bonus Score relay (resized).jpg
If you look at this schematic you can see that it is broken into four sections and that the Bonus Unit connects to the switches of one drop target in each section at a time. When the Bonus Unit is in position 0 (as drawn) it is connected to the switches of all four Diamonds drop targets. Each section also has a Score Motor switch connected to it in a red box. Those four Score Motor switches close at different times as the Score Motor turns.

So in the first Score Motor cycle of counting the bonus the Score Motor 1D switch closes first (as shown in the Motor Sequence Chart). If the Ace of Diamonds drop target is down (and its switch is closed), the circuit completes through the Bonus Unit, the Score Motor 1D switch, a switch on the H/Hole relay (which is closed because we're counting the bonus) to fire the Q/Bonus Score relay (which is an uncommon 6.3 volt relay).

As the Score Motor continues to turn the next switch to close is the 2C switch which looks at the King of Diamonds drop target switch. If the King of Diamonds target is down the Q/Bonus Score relay fires again. The Score Motor then closes the 3B and 1B switches to look at the Queen and Jack of Diamonds, firing the Q/Bonus Count relay each time if the target is down.

When the 1B switch closes to look at the Jack target, another 1B switch also closes (in the earlier schematic) which advances the Bonus Unit from position 0 to position 1.

At this point the Score Motor has run nearly a full cycle (or 1/3 of a turn) and the Q/Bonus Score relay has fired up to four times based on the number of Diamonds drop targets that are down and the Bonus Unit has stepped to position 1. The Score Motor 2B switch that is keeping the H/Hole relay active will open at the very end of the Score Motor sequence but since the Bonus Unit is now in position 1, the Bonus Unit Runout switch will be closed to keep the H/Hole relay active (and the Score Motor running) for a few more cycles.

As the Score Motor starts its second cycle (or 1/3 of a turn) the Bonus Unit is in position 1 which swaps out the four Diamonds drop target switches for four Spades drop target switches. The Q/Bonus Score relay will fire based on how many Spade targets are down. In the next two Score Motor cycles the Bonus Unit will step to positions 2 and 3 to examine the Hearts and finally the Clubs targets.

The result is that the Q/Bonus Score relay will fire up to 16 times over four Score Motor cycles based on how many targets are down.

Whether a target awards 100 or 1000 points is determined by this part of the schematic:
High Hand 1000s relay (resized).jpg
Each time the Q/Bonus Score relay fires it closes a switch that allows a pulse from the Score Motor 1A switch to get through towards the L/1000 point and M/100 point relays. The pulse gets to the Bonus Unit which uses the same four positions to determine which suit of targets we're looking at. In position 0 it's looking at the Diamonds targets so a Make/Break switch on the B/Diamond Sequence Completed relay determines whether the pulse gets sent to the M/100 point or to the L/1000 point relay based on whether all the Diamonds targets are down. That process is repeated for the other three suits.

So to summarize
- the Bonus Unit looks at one suit at a time.
- the Score Motor generates pulses to fire the relays and to advance the Bonus Unit
- the drop target switches are used to trigger the Q/Bonus Score relay
- the B,C,D,E/Sequence Completed relays decide whether the targets for a suit get 100 or 1000 points
- the H/Hole relay stays active until all the targets have been checked.

Any questions? Extra credit to anyone still reading...

/Mark

I love having the workings of these bonus units explained in a clear way....thanks Mark! I think this helps everybody.

Watch the Q relay carefully as the Bonus is counting. It needs to fire for every downed target. When it misses one target in a suit does it always miss the same target? You'll need to listen carefully for the repeating pattern determined by the four Score Motor switches. If it always misses the same target(s) that would point to the target switches. If it can miss multiple targets in a given suit that might point more toward the Bonus Unit stepper.

Or, you could jumper across a suspected drop target switch to see if that makes it more reliable. If it does that would implicate the drop target switch.