Just a bit of useless trivia: I have no stereoscopic vision as I'm nearsighted in one eye (born that way) which might be why I tend to lean towards games with 2 flippers rather than 3 or 4. Its easier for me to make the spinner shot as that can be reached with the lower left flipper, whereas the left shot requires the top right flipper to make it which is difficult for me to line up most of the time.

Something I have noticed anyway.

Posts: What I was using, Bally Xenon and steel post.

Measured where elastic sits .423, .364 and .250 inch.

I added a smaller elastic and the Bally posts, its a little better but still get the odd brick even with plenty of space behind the target.

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Quench

If I'm looking for a mpu lock up condition, what voltages should I be looking at? Mpu locked up during a game again.

Unfortunately the Weebly MPU board has no test loops and I may have to solder leads on.

Symptoms: On three occasions MPU board has crashed, twice with Bally SDB and once with Alltek SDB. On two of those occasions, the flippers continued to operate but everything else was dead including displays aside from GI. The last time it happened, I opened the back and noted the MPU LED was off and hit the reset button which returned it to life.

I suspect its the 11.9v line which is shared with SB-300 and MPU but its just a hunch. I had the volume up to max on the board and I think this is causing excessive draw on the circuit. The question is will a dip in the 11.9V to the MPU cause a lock up? Looking at schematic its part of valid power detection circuit but I can find little else in the way of explanation. The 5V circuit is covered in some depth but not the 11.9v unregulated.

I'll be checking all three on Sunday and see if I can replicate the problem again, its only done it three times out of a few dozen games. I have turned the volume down to a whisper and it has not locked up since but no guarantee as it seldom happens.

Can't play and hold the test leads on. I was going to clip on a meter and play while a camera records the voltages. 3 meters actually.

Excellent! It can be reduced as a possibility then.

Yes.

All flipper coils brand new as are the poppers, diodes present. The issue happens at random. One time it was on the first game inside a minute, another time an hour or two later. I have detected no pattern, but its only happened three times.

Running a 6 ohm, which meters out around 7.

Thank you! Already considering the second playfield "module" a Bally which will be considerably more ambitious.

It wont be Flash Gordon which I'm already well along as a stand alone but in that timeframe. I'm still considering dumping the cabinet and making FG a drop in but we will cross that bridge after the playfield is completed.

Odd, post went missing. Think I hit preview instead of post.

Won't take long and I'm a little ahead of the curve time wise. Can't hurt to have some additional data.

From Pinwiki:

"With the exception of the first four Stern M-100 games, which shipped with a 4-bar chime box, all others use a speaker. And most of them have the speaker mounted on a board, aimed at the coin door. The speaker is a 6-1/2", low wattage speaker, but has an odd impedance of 6.4 ohms. "

The 7 measured ohm is not far off from 8 ohms and at worse will just make the amp circuits work a touch harder in my experience.

I don't think I have checked since doing the initial cab wiring and rectifier testing, I'll get some numbers tonight.

Well I think that might be in my skill set to do =)

Well this will certainly help on the next one.

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Curious and disheartening.

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Played 2 five ball games with my wife and here are the results.

5.0v at the MPU and MPU ground test points pretty much never ever moved. On boot was at 4.99v and quickly went to 5.0 volts and stayed there.

MPU has no 11.9v test point, clipped meter two onto the SB300 connector. Voltage stayed between 15 and 16 volts the whole time.

Last meter was at the 21V test point on the MPU.

EDIT: Reviewing the video, the lowest voltage spotted here was 20.2v, the majority of the time was at 22v range. Dipped into the 20's 3 times with 20.2 being the lowest, 20.9 being the highest.

Edit II: Moved my fastest meter onto the 21V test point and while playing my wife watched the meter. A few times in dipped down into the 19 volt range with the lowest noted reading being 19.6 volts. I'm *assuming* this would be the solenoid voltage dropping down to 39.2 volts.

How far can the voltage drop before the MPU defaults? Will low voltage here cause a default? Inquiring minds want to know!

I'm assuming it can since you explained the MPU used zero crossing for timing purposes.

Solinoid voltage at A2 board, gray wire to zero crossing on MPU at idle.

While the ball was up in the poppers, monkey hammered the flippers which drove the voltage down to 35.2 volts. Not enough for it to trip out but seems low to me.

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The 5 volt line was rock solid, it didn't even twitch.

The MPU was definitely crashed, nothing responded aside from flippers, till I hit the mpu reset button on the board.

I'm going to reroute the 5v and ground on general principle, hasn't crashed in awhile.

Considering pulling the socketed IC and re-seating.

The 2 grounds and 2 five volt lines for the MPU have been removed from the main harness and routed by themselves at the top of the shielded area.

Finally broke a million, had EVERYTHING lit.

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Hope to be printing out light shields in the next few days. Assembled the printer tonight.

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Not sleeping has its advantages

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Two down, two to go.

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Lexan rocks!

Made 3 plastic protectors

Relocated prop rod hole so better angle on PF when up.
Shimmed 3 bank so when drops are down level with PF.

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We be printing!

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38% there

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I'm rather excited!

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Time to design the rest.

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59%

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Work tonight.

Printing out light shields.

Swapped out lamp driver board with one I had already did resistors

Closed gap on upper right playfield. For some reason Stern left the top right open under the plastic and had a spacer. I took the back wood playfield rail piece I replaced due to damage, cut it down and installed it here. Now that light is even and the plastic has proper support.

Only reason I can think they didn't run the rail all the way back is because a single mounting foot for the loop, but I only had to clearance the piece slightly.

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Problem.

The ball has been chattering in the shooter lane 50% of the time. I think I fix it and it returns! What I think is happening is the ball is hitting the steel edge of the metal form and it bounces it into the opposite wall. Because of the spring loaded gate the ball is ALWAYS forced to the right.

If I hold the gate manually open to the left, the ball shoots straight and true every single time, no chatter. I'm either going to countersink the metal form into the wood or file a bevel into the metal.

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Yes it's from Cliffy, it's not that stiff.

Too-do list update 10/27/21

Install driver board with resistors for LED operation *DONE*
Bricking on Stern 3 bank drops, try and tweak. *DONE*
Lexan protection for certain plastics. *ONE TO GO*
3D print light shields *DONE*

Finish aluminum cab/leg protectors.
Tweak left slingshot, still shotgunning once in awhile. still.
Ball chatter out of shooter lane, figure out how to minimize.
Test out blue LEDs for inner loop area. (waiting on package)
Swap speaker.
Spinner graphics.
Cabinet graphics.

Waiting on some Titan Elastics to arrive, fixed another lamp socket, fixed "missing rail" and lamp shields done.

Rest in Peace brother, may we meet again.

Irked the hell out of me the light wasn't even on the top right (extended to the plastic end and cab wall) and the plastic was unsupported.

All to save a few pennies.

Tried blue led in the inner loop, no liking and going to change back to white.

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Lets talk Stern drop targets! I think I have this problem licked. Stern made several changes over the years so no doubt some of this is old territory.

Springs were installed at (B) location. Tried increasing spring tension but this causes drop to "bow" when struck increasing bricking!

Studying the assembly it occurred to me if the lower spring mount was moved inward (A) this would reduce the horizontal spring force exerted on the drop and have it coming at a more optimal angle for pulling the drop downward.

This was successful.

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Having way to much fun with 3D printer... first piece with support.

The purpose? Glad you asked!

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