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Old 2018.01.04, 12:17 AM   #10
BitChar-G
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Join Date: Apr 2017
Posts: 48
Thanks for all the input. Didn't know this was a problem that plagued the AWD chassis.

I took everything apart, reminds me of the MR-01 days, this chassis design is really dated. Did the even change the main chassis between the MA-01 and MA-020?

Turns out I found even more horrible QC issues inside. The front servo stay is broken where the screw goes through, and the piece isn't even inside the chassis. So it was assembled that way.

Same with the plastic bracket that holds the servo potentiometer in place, one of it's protruding "centering" legs is missing, that could explain the failure to return to centre correctly each time, but I doubt it as the bottom is flat, and that should keep the pot centred when all assembled.

Also, more horrible solder joints and the servo motor's ground wire has it's PVC sleeve ripped (probably from incorrect routing and have it crushed) leaving wire strands exposed, rather close to the main PCB...

Back to the issue at hand, no broken gears, servo cover not making contact with anything. I re-assembled the whole chassis whilst leaving out the main PCB and servo components. Problem still there. I tried loosing the lower tie rod cover (this seemed likely to be the problem as every screw was over tightened and most stripped). Problem still there.

I removed the front knuckles, re-tightened the lower tie rod cover. Problem gone.

Inspected the front knuckle area that sits in the tie rod, noticed there are some protruding mold marks. Looked inside the tie rod where the part of the knuckle sits, found some more plastic protruding mold marks.

Re-assembled everything (still without the servo components) and noticed the binding is actually occurring when the mold marks from both the knuckles and tie rods do NOT make contact. Leads me to believe the issue is simply in the design of how the knuckles connect to the tie rod in this chassis. I still don't know why Kyosho hasn't switched over to regular ball joints like 1/10 cars with the Mini-Z line.

I suspect the problem will be resolved once I polish the parts of the knuckles and tie rod that make contact. Don't know how I'm going to go about that yet, only have some coarse files and don't want to create excessive play or friction.

Has anyone successfully eliminated the problem from their AWD Mini-Z chassis without extreme measures? My MA-020 is all stock with OEM Kyosho parts.
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