Snow Derby - Repair/Restore log

Talk about electro-mechanical pinball machines
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Snow Derby - Repair/Restore log

Postby trueno92 » Tue Jul 04, 2017 2:19 pm

ok I got about 20 hours into this now so I figure I should log what it is that I am fixing, breaking, fixing as I learn what happens in an EM/electro mechanical Pinball machine.

I picked this up from a seller close by on Kijiji. Really nice people and honoured the listed price of $150 - many people called and quite a few threw more money trying to snake this from the seller. Been in extremely light Home use for the last 28 years and as a result, Its a strong 7/10 with some light playfield wear, some touch-ups done but otherwise there are only 24872 plays on this and it shows, the BG is overall good, light flaking but been retouched, and all the switches and relays inside are in great shape, without any abuse, hacks, or general messing around - if something went out of adjustment, they just played it less.

That pattern also ends up making a game that is well overdue with an accumulation of adjustments and things that need to be fixed... so my log begins:

Problem: Cannot credit up game, or credits don’t count down, or up. Games can start but not consistently.
Diagnosis Credit Stepper motor – Aligned incorrectly, Reel was taken off housing and installed incorrectly, did not line up,
Solution: Set free play by bending credit switch and re-aligning max credit pin back to factory,

Problem: Missed scoring, scores going to the wrong player, player 2 when only 1 player, player 2 sometimes turns on. Game gets confused with how many balls left between players, or just p1.
Diagnosis: Listen for 4 clear ratchet noises from the player unit between players. If 2 player, it snaps from P1 to P2 in 1 and then 3 more after alternating back for P2 to P1. There is a 4 pulse snap as the wheel turns and the contacts on the back need to line up. However, lining up doesn’t matter if the limits are off on the unit solenoid as the resulting ratchet teeth are not going to ratchet consistently.
Solution: Player unit – Cleaned, realigned bakelite disc, checked switch stack gaps, rebuilt and adjusted solenoid for stepper, adjusted ratchet gear cluster and reset linkage limits for ratchet travel. NOTE: ratchet gear needs overthrow for about ½ tooth to not overstep when cycling through players. Ran for 10 plays and then recentered bakelite disc based ON BALL IN PLAY LIGHT INDICATOR ON APRON.

Problem, ball falls into kick out hole and does not kick back out, scoring keeps going infinitely until machine needs to be turned off.
Kick out hole switch adjustment.
Diagnosis: Regapped switch, problem returned after a few plays. Switch looked to be replaced, but ½ bakelite spacer on the back of the switch is missing. Switch tends to go out of gap alignment – re-adjusted, but went out of alignment again - switch needs to be backed with something to prevent it from folding over and going out of alignment. Cut a spacer and replaced – appears to work fine after multiple plays.

Problem, Lights indicators for bonus advance track (every 10 pts), don’t turn on/alternate, when they should on each 10 pt shot score.
Diagnosis: Identified AS relay (match stepper, mini stepper, mini advance relay, advance stepper, f relay) and contact pads were out of alignment on rotating contact plate.
Solution: Adjusted wafer board for plate to center on each advance. Readjusted and gapped relay, adjusted spring for correct return on relay engagement.

Problem, lights for End of play bonus ladder not lighting when it should,
Diagnosis, thought it was a ground circuit that was not tied down. Traced the issue to the Bonus stepper motor under the playfield. Bakelite not aligned,
Solution: Realigned bakelite disc on first advance – so engage the first advance lap, align disc for the lap indicator to light on lap 1,

Problem: Light inidicator is working, but always starts lap on one indicator behind the start line, light indicator is one light off on each advance, bonus counter works but its one position (-1) to where it should be.
Diagnosis: Identified AS relay (match stepper, mini stepper, mini advance relay, advance stepper, f relay) opposite side to lap bonus counter, is another stepper wafer board, contacts are burned at position (-1) just before position 0, appears wafer board looks for continuity across all positions on the dial except position 0 where there is no wire soldered to that lug on the board.
Solution: dropped solder directly on the wafter board and rebuilt contact pad at burned areas and ensured position (0) to be out of continuity. Looks like this tells the motor to keep triggering or sweeping until no continuity, and now when it gets to position (0) it stops correctly.

General tuning, regapped spinners, flippers, adjusted EOS, checked pop bumpers for switch gaps, rubbers, bulbs, and sling adjustments for sensitivity and scoring.
Recentered plunger and recreated a double sided example of the Ball-in-Count card. that the light can shine thru.

Going to leave the cab beige but will re-stencil over it.

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Re: Snow Derby - Repair/Restore log

Postby trueno92 » Mon Jul 10, 2017 9:44 am

another thing:

Scoring bonus changes on 4th and 5th ball which is normal. SOmetimes 5th ball scoring bonus would happen on 4th ball and carry over to 5th ball. Bonus outholes would be lit on 4th ball and bonus scoring on 4th outhole would happen even if not lit.

Sometimes the 5th ball scoring relay would not reset correctly, remain held down on previous game

Inspected 5th ball scoring relay,
Relay can reset, but the relay plate would sometimes slip slightly and not complete the reset. Moved relay spring 2 coils closer to tighen the tension on the plate.

Seems to work fine after 20 consecutive games (reset cycles),

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Re: Snow Derby - Repair/Restore log

Postby trueno92 » Mon Jul 10, 2017 9:49 am

outstanding issue, if anyone can help

AS MINI STEPPER is operating fine, however reset on balls 2-5 trigger the AS mini to go to home zero position. When passing position 9 to position 0, the lap counter triggers on reset and this adds 1 lap to the bonus ladder, Result is ball 2-5 starts with 1 lap bonus instead of 0. Lap bonus only scored on drain, so there is not score when the light triggers.

Operation is normal if ball in play, but don't know why this is being triggered on reset.

ITS THE ONLY LAST NIGGLING PROBLEM!~! the game works great, but if I could have this figured out, it would help!

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Re: Snow Derby - Repair/Restore log

Postby trueno92 » Tue Sep 12, 2017 3:12 pm

updating this:

the mini stepper was actually incorrect for this game.

a fellow on pinside graciously shipped me the exact unit I needed FOR FREE, and with some adjustment, and a quick transplant of parts from my super low mileage Match Stepper, I had a perfectly working and adjusted unit.

It played good, but i i noticed some things not making sense.
1. score reel on 10's would sometimes skip ahead on bonus countdown.
2. on ball 1-3 the spot advance would sometimes continue advancing on bonus countdown.

step 1 would be an easy fix but a lot of diagnosis.. as I didn't think of looking at the reels first. i cleaned it, and made sure it moved freely, checked the 10pt relay etc. it turns out all that it needed was the decagon spring to be slightly bent to stop the wheel from bouncing ahead on recoil.

after a few plays, it looked good and started to accurately keep score again

step 2, the spot advance had my pulling my hair out and I eventually gave up thinking it was just too old or something that I don't know was out of adjustment and I could not understand how to repair it.

Turned out I eneded up breaking a brass tongue on the credit unit and it controlled a switch stack that 1, counts score, 2 advances the player unit between balls played and 3. advances the Spot advance.

I didn't understand how this worked, and didn't realize that it connects more than just a single circuit but a series of them. I bent some metal to fix the tongue and regapped the switch stack. This got things going again and the scores on the 50pt wouldn't score.

I regapped the 50pt switches and checked the 10's relay as the 50pt must cross into the 10pt to ring out the 10pt relay 5x.
After that, and an hour of play, the game OPERATES PERFECTLY.

its scoring properly, its bonus countdown is correctly triggering now, as it was missing the occasional bonus step up. I think that switch stack mentioned earlier has to be open for the lap bonus to work correctly.

Oh and finally, the spot advance HOLDS on the bonus countdown for balls 1-3. It works better than any of the existing video examples on youtube!!

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