How to Mod the Green CHM

[vic7767]

I agree also, they've had over 7 years to do so.

[mfortuna]

It would seem the cost of replacing CHMs is less than the cost of sealed bearings. The bean counters are in control.

[sageman]

sun dog "found this forum when searching for the correct lubricant to use (lithium grease)"

lol how i found it aswell

[vic7767]

lol how i found it aswell

Yea ! This is a great site !!

[soviet911]

Just finsihed the mod, and fixed the broken bumper sensor. it works great, for those who want to do the mod if it doesnt work right away make sure your bearins are parelle to the gearbox so they are not inserted at an angle. And also make sure to put on that piece of tape otherwise it might not work right away!

[Nitrowing]

I rebuilt the gearbox this time using a dab of copper grease instead of the slightly thicker grease I had been using.

Please remove all traces of copper grease ASAP!
It is an anti-seize compound NOT a lubricant and will wear all mating surfaces.

[vic7767]

White Lithium grease is not that hard to find. In the future after that copper anti seizing product is removed per the suggestion by Nitrowing, Lithium grease should be used sparingly.

[beerorkid]

I get paid tomorrow and will be placing an order for 2 sets of the bearings from ya vic7767.

I was wondering if you could list off the sizes of the holes you used the step drill to make. I stopped by a hardware store and they wanted $37 for a step drill bit. Looked on amazon and found this 3 piece set for cheap. I figure that will have enough sizes to get the job done.

[vic7767]

The hole sizes are just about the same size as the ball bearings. I'll mention them again here but they are also mentioned on the first page.

(1) 6X10X3 mm - Brush motor shaft
(1) 10X15X4mm - Rubber brush gear
(1) 15X21X4mm - Large brush gear

[beerorkid]

Gotcha.
Was more referring to the standard sizes on the step bit though. I am sure it will be pretty easy to figure out. Thanks for sharing your method. I know it is not going to be a piece of cake, but am used to messing with stuff. I just started working on my own pinball boards and love it. I do have a dremmel, but I would guess a step bit would work better.

Hoping your 500 series DVD will assist me with some other issues. Expect a paypal tomorrow.

[vic7767]

I don't use those particular stepper bits you referenced. Here is a picture of the bits I use for the Green and Red CHMs. I use different bits for the Black one. The picture on the left is of a 3 piece stepless bit set and I only use the middle one to make the opening for the rubber beater brush bearing. The one on the far right is the one I use for the brush motor bearing and the large brush bearing.

[beerorkid]

Cool. Thanks a bunch.

http://www.amazon.com/Irwin-10234-Unibi ... B00004THZ0

[CleanMe]

How are the bearings held in place? Is it a force-fit, or is something like super glue used to anchor them?

Thanks.

[mfortuna]

Friction fit unless you make the holes too big or shave too much off the gears. A little super glue or silicone adhesive will work.

[beerorkid]

Vic, Thanks very much for posting the process and pictures! Question, is the process (or parts) different for modifying a red/blue CHM?

The unknown factors when deciding to install a Sealed ball bearing into a CHM that has been used and has some wear and possible heat damage are present diameter of the brush gear and the present diameter of the brush gear housing. If the CHM has not been used then the same size bearings that are installed into the Green CHM can be utilized and the process is the same.

I have a red and a green. The red has a bit of warping from heat. Should I avoid trying to mod it? I feel confident I can work around the warping on the big gear and still get it to fit.

[vic7767]

Visible damage to a CHM and a choice to perform the ball bearing modification becomes an individual owner choice. The mod may work fine or not depending on the amount of damage.

[speedy]

Has anyone tried the 17 x 26 x 5 mm size in any CHM or the 15 x 21 x 4 mm is the recommended size to use?

Regards

[vic7767]

Those sizes are used but it depends on the CHM model. The Red and Green CHMs should have the 15x21x4mm bearing while the Black CHM should have the 15x24x5mm bearing. The 17x26x5 has been installed in the Black CHM but much less plastic is removed from the brush gear case if the 15x24x5 bearing is used.

[speedy]

Ok.

But can the 15x24x5 works with all CHMs?

[vic7767]

No, it is best to use the 15x21x4mm for the Red or Green CHMs.