cox ez bee sanwa 80111 servo trouble

Hi Steve and welcome….For my own airplanes, If a servo is being balky (or any other electronic component), I simply replace it, It’s not wort crashing the plane…. Servos are relatively inexpensive these days…. Assuming everything else in the system is working OK…

But to try and help with your question if you still want to try….And assuming everything else is OK…. Open the servo case and inspect for any loose or broken wire connections from the three wire cable to the printed circuit board (PCB)…..Inspect the PCB for any corrosion…. Sometimes old solder flux will cause corrosion and cause some of the traces to bridge…. Use rubbing alcohol and scrub with an old toothbrush…..

Inspect the plastic gears for old hardened grease…. Scrub and clean if needed with the alcohol….. Check the gears for cracks or missing teeth….Re-lube with a light coat of white lithium grease…

Check wiring to the electric drive motor and that it will turn freely….

The feedback potentiometer is a three wire gadget under the main servo gear…. Make sure the wires connecting it to the PCB are secure… Some of the older servos had two screws holding the feedback pot cap on… If yours has those open it up and clean the carbon trace and the copper wiper with alcohol and a Q-tip… Lube lightly with electrolytic grease and reassemble… If the servo ever stalled and remained there for a length of time the feedback pot could over heat and be damaged …

Those are surface level things to check first…. Let us know how it works out for you…

thank you everyone! when i get home from work i will inspect the servo internals! I just found it strange how the one worked and then died so suddenly! in the mean time if anyone has a spare set of 80111 i would be interested in giving them a try! excited to try and get this thing in air!

balogh wrote:Just wondering if the 6V is not too high for the servo? At least the servos I use are fed with less than 6 V but higher than 4.5V.

András, I think these systems came with a dry battery pack for 4 AA batteries, which would then be 6 Volts (1.5Vx4=6V), but would work with optional Ni-Cad (or Ni-Mh, 1.2x4=4.8V).

so while at work my father put more than 6 volts too the reciever and the servos are working again, ii suppose its a voltage issue.. but when we put the multimeter on the battery box we get 6 volts. hmmmm....

Steve, The voltage range should be as @GallopingGhostler mentioned…. Between 4.8 and 6 volts…. Four fresh alkaline AA’s may be slightly more when new but will not hurt anything…. A true voltage test will be measured with receiver on and servos moving …. Possible suspects in the power supply;…. If it has a spring loaded battery box contacts could be dirty…. Think of bumping on old flashlight to make it come on….I’ve even seen these plastic boxes crack causing intermittent connection…. Dirty switch… Dunk it in alcohol and work it a few times….

Brand new alkalines will put out a touch more, say, 1.63V is not unusual. So with new batteries, a total of say 6.3V is normal and this will not harm the flight electronics.

Are the battery contacts a little dirty? Not making consistent contact? How are the switch assembly contacts?

I'd go through everything with a "fine tooth comb".

Not sure, but were the Sanwa servo connectors compatible with Airtronics radios?

Personally I would clean them and a good lubrication. When it doesn't move super slow i trust them if it works well but I prefer to use in rc cars For an airplane I prefer new 2.4g controller with better range, more reliable I changed the servo motors on mine and used smaller one which did the job.
For information, this receiver and servo system is not compatible with standard now-day systems The wires in the connector are reversed Do not plug servos other than the model designed for this receiver

There has been some timing changes in the newer systems, haven't kept track of all the specifics with the servo's signal line.

I jumped on it before these evaporate, but got a Hobby King universal 2.4 GHz transmitter module and Corona receiver, so I could put one of my older transmitters on the modern frequencies.

Another consideration is going for my GROL - FCC General Radio Operator's License. This would allow me to legally tune and modify commercial radio systems. Been a long term dream of mine but never jumped on it when I was busy with work.

Of course, changing out the radio's transmitter section with one already factory tuned would not require this.