Telemaster 56

This happened to me a few years ago and to a friend of mine yesterday! We had both experienced the effect of a dirty joystick pot (potentiometer) the variable resister that is moved by the joysticks in your transmitter. There are two pots in each, one for the X axis and one for the Y axis. If one or more of the pots become dirty the control surfaces on your model move eratically instead of smoothly when you move the joystick.

The normal method of cleaning a dirty pot is to spray "contact cleaner" into the pot and then move it back and forth. Contact cleaner comes in a spray can with a plastic tube to insert into the nozzel head to get the cleaner into small areas. I took the back off my Futaba transmitter and sprayed the cleaner into the two pots. A few seconds later the entire joystick assembly flew into small pieces! What had happened was the cleaner chemical had reacted with the black plastic material that the gimble assembly was made out of and softened it instantly. The tention of the two springs then caused the whole thing to fly apart, totally destroying it! In my friends case, when he lifted the transmitter after spraying the pots his joystick handle fell out of the gimble assembly.

I had to purchase a new joystick assembly and my friend will have to do likewise.

Since dirty pots do happen I'm hoping somebody in the forum has a solution to this. Possibly some form of cleaner that does not react with the plastic. I was using a type sold by electronic supply houses for cleaning relay contacts, switches, TV tuners etc. I don't remember the brand name or the chemical used.

There was no warning in my user manual for my transmitter, a Futaba Super 7 about this. Again, if anyone know how to clean dirty pots safely I'd appreciate knowing how they did it.

rc-sport

My Feedback: (12)

There was article in one of the RC rags, I think Model Aviation about this very thing happening. They had before and after pictures.

voyager_663rd

Very interesting. Thanks for the heads up (sorry it was from personal experience though). []

Airbus 9e

Try Radio Shack. They used to sell stuff called "tuner cleaner"....If you look at the directions, it will tell you if it's intended for use on plastic parts.

redbluffwingnut

My Feedback: (2)

i have 16 fataba radios and never had a dirty stick problem and i still use the 4 channel radio the i learned on you must live in a dirty area for this to be a real problem as far as how to fix it i don't know, any time i think i may be having a problem with trans i send it in and let them fix it (cheaper then killing an airplane)

grotto2

My Feedback: (2)

I have to 2nd redbluffwingnut on sending it in. I've had problems with top-of-line transmitters, too.
For one thing, the plastic ages and cracks through normal use. A friend of mine had a tiny crack in the stick assembly that gave him slipping trim problems for years until he figured it out.
Secondly, the symptoms do not always point to a potentiometer problem. Sometimes it can be a break in the wires leading up to the pot, and you can troubleshoot in circles trying to figure it out.
Send it in to a good radio shop and let them deal with it.
-grotto2

mulligan

grotto,

Nice to "meet" you. Where do you fly (Indian River?), and have you visited our field (Sanford Aero Modelers)? If not, swing by some time. We have about 120 members and always welcome guests. Our next meeting is at our field on 2/19, which should make for an especially popular day. Visit our website for more on the club.

Deadeye

How about isopropyl (rubbing) alcohol? I've used that stuff on a variety of electronics over the years. Back in my car days, I would clean the motors by plugging them directly into a battery, and submerging them in a jar of iso alcohol. Worked like a charm. Same thing for RXs, just pull the case off, and dip it in a jar, remove it, brush lightly with an old toothbrush, and rinse in iso. Worked great, and I have never seen iso attack any type of plastic. Good luck.

Robotech

My Feedback: (9)

While the term commonly used is " dirty " pot is is usually a matter of wear not dirt that causes them to fail. If faced with a malfunctioning potentiometer the best solution is replacement not spraying them out with cleaner.

Also I would be willing to bet that somewhere on the label of the spray cleaner in very small print it says to test on a non critical part of the plastic first. [sm=surprised.gif]