I am trying to get a great planes cherokee back in the air after a long time in the hanger

I am wondering if the servos are shot?there are 4 brands (futaba,cirrus,jr,hitech) with the hitech being new and they all hum,the jr more than the others is this normal or do I have a problem.

would the battery being at less than full charge cause this??

thanks in advance

What model numbers are the ones that are humming. Are they digital servos? I ask this because digital servos will hum and it is perfectly normal for them to do so.

Ken

Could be the transmitter is off or too close. Do they hum just sitting idle with the transmitter on ("on first, off last") and 10 feet away?

Could also be low battery, fighting tight or bottomed out linkage (especially the throttle full open/closed), fluorescent lighting or electric motors running nearby.

You have that many different makes in one plane? Yowzer! Are they compatable with the receiver? Some are positive shift and some are negative shift. I know Futaba and HiTec are compatable, I think JR is also (as is Airtronics, i think). Cirrus (vintage stuff!?) I have no idea and I'm not sure if it plays well with Futaba. I guess you'd know if it moved when you moved the stick.

Since these have "been a long time in the hanger" the cause is very likely sticky hinges or pushrods. Do the surfaces move freely if disconnected at the servo end (leave push rods engaged)? Are there any extensions that may have dirty or corroded connections? Yes, low battery can cause this. Age or storage does not normally degrade a servo itself, if they worked well initially, they are most probably still okay.

Rodney is most likley onto your problem. If the battery as been around for quite a while chuck it (recycle) and get a new one. It will cost you the plane somewhere down the line if you arn't careful.

Correct me if I'm wrong but I don't think servos are shift sensitive.

Right, servos don't have shift, that's only an issue between the TX and RX. Between the RX and the servos, they are all the same. I've flown more than one plane with a mix of servos of several different brands with no problems.

it's probably like Rodney said. Another thing you can check is take the servo arms off of the servos, so they have absolutly nothing keeping them from turning. Now see if the noise is reduced. While you have the linkages disconnected, move them with your hand, and you can feel what the servo is working against. Hopefully not much friction.

It should be simple to start troubleshooting by taking the wheel off the servo one at a time and see if the hum starts to disappear.

Bill

I disconected the horns and the huming stoped on the rudder servo(jr),the others just hum when they are moved. I charged the battery and that seemed to help but that jr servo still hums when its at rest.

I changed it out to another jr servo and it humed too,I can wiggle the nose wheel and it stops

Ah. Thank you. Further up the line. I knew at some point there was a compatability issue.

Jr servos require some wire swapping if used on a hitec or futaba this could be the problem. What radio is it?

"Jr servos require some wire swapping if used on a hitec or futaba this could be the problem. What radio is it? " is not correct. All modern receivers have the same wiring for the servos; the center connector is positive, the outside lead (one closest to the edge of the receiver) is negative and the other is the signal. The only ones different is the very old Airtronics where the negative and positive wires were reversed.