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Old 2018.10.18, 02:16 PM   #1
mugler
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Do MR-03/MR-02 2.4 "ASF" boards get slower with time & use?

Haven't been able to dig up any conversations about this...what is known about 2.4 ASF brushed boards (03's including tiki / 02's) slowing down with age & use?

I have a fleet of them & one by one they slowed down on their top & bottom speeds to a point which are not usable any longer. Specifically when I run them on a freshly charged pack they start the run at about 85% of their normal top speed and less than 10 laps in they slow down considerably to like 70% of their initial speed and keep getting gradually slower and slower. I noticed the motors get mega hot as well in a short period of time. the problem is even worst with the heavier F1's.

Background of these cars are they are aged and have many-many miles on them. I tried using brand new motors to eliminate the old motor factor but the same thing kept happening with all of them. Even had one of them re-fetted professionally with all brand new FETs 2 stack deep and to my surprise it didn't help one bit, if anything it got worst. The gear mesh was always checked and perfect too.

Does anyone have an idea, is this just a function of old board building up general resistance in all of it's components or something else with a cure?

Last edited by mugler; 2018.10.18 at 02:26 PM.
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Old 2018.10.18, 04:23 PM   #2
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If it was an 02 ASF board I would suspect the switch on an 03 I don't know. Sounds like a high resistance connection somewhere.
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Old 2018.10.18, 06:21 PM   #3
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I noticed my buddies mr02 is very slow... put a brand new broken in motor, and it's still slow. Need to go over it, but might just swap the board out for a clone board. This board has only ever run 70t motors of I recall correctly.
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Old 2018.10.18, 07:02 PM   #4
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Quote:
Originally Posted by mleemor60 View Post
If it was an 02 ASF board I would suspect the switch on an 03 I don't know. Sounds like a high resistance connection somewhere.
on most of these boards the switch has been removed. I agree about existence of resistance being the general cause. One suspicious area might be the -/+ tab plates on the board. On all of them at some point I changed out the stock board to battery tab wires and was very surprised how tiny and fragile those solder tabs on the boards are. some looked like ended up with very little solder on them but even the ones with solid & clean solder jobs are still slow.

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I noticed my buddies mr02 is very slow... put a brand new broken in motor, and it's still slow. Need to go over it, but might just swap the board out for a clone board. This board has only ever run 70t motors of I recall correctly.
I have a newly installed clone board and as mentioned by others there's massive potentiometer correction going on when no throttle is applied but it doesn't seem to effect the steering when the car is running...I wonder what others are experiencing and if old school motor caps help?
Funny enough the speed of the clone is also somewhat slow and there is still some fading after running the car for more than 5 mins. This weekend I should be able to test with a brand new 70TBB motor and play with the board settings to see if those things can be optimized.
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Old 2018.10.18, 09:23 PM   #5
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Have you tried cleaning and bending out the battery contacts? It could be possible that they aren't getting good contact with the cells
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Old 2018.10.19, 03:59 PM   #6
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Have you tried cleaning and bending out the battery contacts? It could be possible that they aren't getting good contact with the cells
Yes I did check those and also cleaned them with rubbing alcohol and didn’t notice any difference. I also changed the motor wires that had seen a lot of soldering and no difference was noticed there either.

According to a local top-flight 1/10 scaler who races mod they prefer to use a brand new ESC for every big racing event, supposedly even after one weekend of use the esc’s see a drop in performabce, so i guess putting all those miles on these asf boards or any esc eventually wears them down and maybe theres a point where the performance just drops off the cliff.
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Old 2018.10.19, 06:43 PM   #7
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I have boards that are years old with I bet over 100 battery packs ran thru them and I do not see any performance issues in them.

One thing that I did have once was a pinion that would start to slip on the motor shaft after a minute or so and I thought that the board was going bad. After I put a new pinion on the issue went away. Give that a try. Hope it helps.
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Old 2018.10.19, 07:19 PM   #8
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Mugler, is there a power switch installed? Have you tried bypassing it?

I have some boards that are a little slower, but I seem to remember them always being slower.
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Old 2018.10.20, 10:25 AM   #9
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I've noticed that every once in a while I need to reset my endpoint travel. I think I'm explaining this correctly. You know, when you turn the wheel full left and full right and push and pull the throttle full forwards and back.

Kris
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Old 2018.10.20, 12:32 PM   #10
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switch bypass, pinion slip check and Tx VR adjustments are all good items to look at ...I'll choose one or two of these cars and start checking everything on them systematically.

Quick math tells me my slow cars easily have over 300 battery packs run through them over the years & all of them were fast when new and got slower gradually and at some point even slower quickly. I swap power wires that run on the board itself so perhaps that would be the other area that might have caused issues.

I'm not able take a picture now, but when it comes to bypassing the switch I know about soldering the two switch tabs on the board together to make that happen but also noticed that if the positive tab is also included in the switch bypass solder joint the car still works as normal but are there any thoughts if that may have anything to do with slow speeds?

Last edited by mugler; 2018.10.20 at 01:23 PM.
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