After eight long years of being folded up and buried in the garage, I finally got to set up Earthshaker and begin renovations. I purchased it long ago and only had a short time with it before personal, family and work matters led to long term storage.
100_8640 (resized).JPG
Mostly in good condition, it plays 100%. Backglass is perfect.
Playfield has a few small worn areas that previous owner left for me:
100_8643 (resized).JPG
Looks like the interconnect board needs replacing or major GI repairs:
100_8629 (resized).JPG
I took out the processor board for cleaning and installation of Frank's coin battery board:
100_8634 (resized).JPG
I had removed the batteries before storage, and the board looks perfect. I can see that several transistors were replaced previously.
My family really likes Earthshaker and kids enjoy playing. Probably a keeper.

Previous owner made this mess, but it does work. I plan to remove the interconnect board and see what, if anything, can be done to fix this.

I decided to start ES renovations on the shaker motor. That way the game can still be played by the grandkids while the motor is out.
Original shaker motor does work but always seemed weak especially compared to other games we played over the years. Here is my original:
100_8647 (resized).JPG
removes easily, one wire connector and 4 mounting screws. Easy to disassemble into parts. Lots of dirty black motor dust:
100_8657 (resized).JPG
The two carbon brush holders snap into the motor and pull straight out for removal, no fasteners. My red side brush was almost twice as long as the white side brush. The white side brush fell out of the holder, the braided wire was broken off. Certainly contributed to poor motor performance:
100_8654 (resized).JPG
100_8656 (resized).JPG
The metal mounting brackets cleaned and painted:
100_8665 (resized).JPG
Original Johnson HC970 series motor:
100_8664 (resized).JPG
Quick internet search shows this Johnson motor is very popular with RC model boat and car builders. Comes in several shaft configurations, and sizes. I bought two NOS single shaft motors on EBay ($36 total), primarily for the brushes and plastic holders. I also found 5mm by 7mm brushes on Amazon for less than $4 each and bought four to try out.
Still working on the set screws in the offset weights.

It appears to me that loctite was used on the setscrews, three came out without much of a fight, the fourth twisted the allen wrench then popped loose. the set screws have a deep socket so the allen wrench contacts a large surface area inside.
100_8670 (resized).JPG
100_8671 (resized).JPG
I had soaked the setscrews with penetrating oil for two days before attempting removal. They are 8-32 by 7/16" long.
I usually scrub the metal parts clean with comet powder, hot water, and a green scrub pad to remove all the crud. Then rinse and dry thoroughly and set in the sun for an hour to ensure things are completely dry. The paint I have taken a liking to is Rustoleum Metallic Titanium Silver. I think it really looks good on clean parts. Around $6 a can, I get it from the local Ace hardware store.
100_8669 (resized).JPG
100_8672 (resized).JPG
The brushes and motors I ordered should be here in 3 days, then I will reassemble and reinstall.
Good luck with your set screws, I did not use the torch to heat the weights, but I did look over at it and seriously think about it!

And I always clean and paint anything I take apart, even if it will be hidden later. I want to make sure anything I do stays done (correctly) for a loooong time.

Success on the shaker motor renovation. Assembled and ready to install:
100_8681 (resized).JPG
Installed, tested ok and working. It does feel a tiny amount "shakier" than before:
100_8687 (resized).JPG
The motor brushes were borrowed from the new motors and were exactly identical. I used blue loctite on the 4 weight setscrews.
It scared the grandkids the first time it activated during a game!

Question: the promo flyer shows no center post between the flippers and two of the metal rails directly behind the flippers:
100_8691 (resized).JPG
My game does have a center post and no holes drilled in the playfield for metal rails:
100_8690 (resized).JPG
I searched the forums for some info but nothing came up. The playfield parts list in the game manual shows the center post, so I assume it was added to all games during production.

my shaker motor is set at ARCADE in the menu. It does create quite a racket after a couple of seconds.

shaker motor weights are both pointing straight down when not rotating. This is mine before I put in new motor brushes, that helped greatly:
100_8650 (resized).JPG
after cleaning and painting:
100_8681 (resized).JPG
also put loctite on the weight setscrews.