Looking for help please

[jtracks]

I recently picked up a used M-26. It came with a new set of steel gear boxes that weren't installed. I ran the tank with the old gear boxes and other than a couple of bad gears, all was good. I changed the gear boxes yesterday and now when I start to advance the throttle, the speaker makes a loud crackling noise. So I figure that I have a motor than is causing some sort of interference. So I unplugged the left motor and ran the tank, no noise. Plugged the left motor back in and unplugged the right and ran the tank, no noise. So the problem only exists when both motors are ran at the same time. I have checked the noise suppressors on both motors and they are all soldered tightly. I didn't change the speaker because it didn't make the noise with the old motors. So does anyone have any ideas as to what the problem might be? Thanks for your help.

Joe

[ALPHA]

Greetings Jt...try switching the motors.... meaning the ones that were in the stock boxes..with the ones with the New boxes you just put in ...should solve the problem

ALPHA

[jtracks]

Thanks ALPHA for the reply but I don't want to do that. The motors that came with the new gear boxes are stronger (more torque) than the stock motors, part of the reason for the upgrade. I'm now thinking that maybe one of the noise suppressors are bad internally. I'll change them all and see what happens. Any other thoughts, I'd like to hear them.

Joe

[ALPHA]

Thanks ALPHA for the reply but I don't want to do that. The motors that came with the new gear boxes are stronger (more torque) than the stock motors, part of the reason for the upgrade. I'm now thinking that maybe one of the noise suppressors are bad internally. I'll change them all and see what happens. Any other thoughts, I'd like to hear them.

Joe

Well...maybe as a "trouble shoot JT....if it works...then check the wires on the new motors...and also the resistors...make sure they are installed polarity correct...and if all fails...just take the resistors from the old motors and solder those on to the new ones

ALPHA

[jtracks]

Yes, switching the resistors was my next move. Thank you.

Joe

[ALPHA]

Yes, switching the resistors was my next move. Thank you.

Joe

Yeah...it sounds like something to do with that area of construction...never can tell ...even with factory quality control ...a defective one can slip by...or could be installed incorrectly

Good Luck JT

ALPHA

[wibblywobbly]

Assuming that there are capacitors on the motors that are causing the interference (some are internal, some are external..and some are assumed to be internal but not all manufacturers fit them), then it's either a bad solder joint, a bad capacitor, or could even be motor wires running too close to components.

You can try:

Checking that you have all three capacitors on each motor, two are one value, the third is another.
Try twisting each pair of motor wires seperately between the motors and the plugs, as that will cut down on the interference that they emit.
Try a thick piece of plastic card between the motors and the rest of the electrics.

RobG

[jackalope]

My King Tiger does the same thing that I'm building however I found if I move the steering trim tab just a little off the setting that makes the tank drive arrow straight it stops most of the time. I'm gonna try twisting the wires and see if that helps any but if not I'm thinking if getting an in line noise filter for the speaker that would be used in a car radio.

[jtracks]

Assuming that there are capacitors on the motors that are causing the interference (some are internal, some are external..and some are assumed to be internal but not all manufacturers fit them), then it's either a bad solder joint, a bad capacitor, or could even be motor wires running too close to components.

You can try:

Checking that you have all three capacitors on each motor, two are one value, the third is another.
Try twisting each pair of motor wires seperately between the motors and the plugs, as that will cut down on the interference that they emit.
Try a thick piece of plastic card between the motors and the rest of the electrics.

RobG

There are only two external capacitors per motor. They have the number 104 on each of them. I will try twisting the motor wires and the plastic. Thank you for your help.

[jtracks]

My King Tiger does the same thing that I'm building however I found if I move the steering trim tab just a little off the setting that makes the tank drive arrow straight it stops most of the time. I'm gonna try twisting the wires and see if that helps any but if not I'm thinking if getting an in line noise filter for the speaker that would be used in a car radio.

I'll give the trim a try first, maybe I won't have to open the tank up again. Thank you.

Just to let you know what I did today after my first post.

Plugged the old motors back in, no noise.
Tried one old motor and one new, no noise. x2
Switched the capacitors between motors, noise.
Removed the capacitors from the new motors, noise.
Tried the old motor wires and plugs on the new motors, noise.
Sprayed motor cleaner into the motors, noise.
Checked for arching within the motors, none evident.