apereira

After 7months without flying a specific aircraft, when I went flying, installed a new batt 6v 1100mAh Jr extra, with JR R770S receiver, and the two elevators and rudder servos did ot move, rudder 5625 elev 5425, ailerons 5625 moved normaly and thr HS81 also was ok.

After inspection at home, the servo programmer could access the software succesfully, but still no movement, after taking the bottom cover off, all three servos had the electronics visibly damaged. Any idea of the repair price if the electronics have to be completly replaced and that been the only damage?

I'm sending the servos back to Hitec for repair, but, any idea what could cause this?, I have close to 30 Hitec servos and never had any problems operating with 6V with no regulator, I only use JR batteries and receivers, could the receiver send power to the signal wire and destroy the electronics?(curiosity), I did not checked the voltage or pulse from the receiver with the programmer because I will send the receiver out for check and didn't want to take any chances.

Thanks in advance for the advises.

Alejandroi

mglavin

My Feedback: (31)

Its hard to say as there are to many variables inplay. Its odd that two idepenedent channels failed with apparent component damage witihn the servos and all else functions. Were there any problems last time the model was flown? Was the battery left in the stored model and was the model assembled?

apereira

Thanks for the replay,

Yes the model was assembled, I flew the model many times with no problem, I stop flying it due to work and other airplanes, I had the elev servos in separate channels and the three servos in the tail , the only problem I got was my YS 110 powered by 30% nitro, broke the exhaust deflector and the smoke ended venting through the inside of the model. I did not noticed any gum inside the servo electronics at all, but the 5625 was hard to turn by hand and upon inspection found to be the motor that is hard to turn, it turns but as freely as it should. The battery died in the airplane when stored, I don;t remember if I left it connected or not, that's why I used the new battery, remember the battery had close to 7V when it was charged, I checked the battery as I always do at 1 Amp load for 5 sec, before powering the airplane to stabilize the peak.

I use JR for radio and Hitec for servos, I really would like to know if it was my fault so it doesn't happen again

mglavin

My Feedback: (31)

I really can't provide an answer that will satisfy your needs as your situation simply does not point any fingers at specific failure modes (based on the information provided).

Generally speaking servos fail when binding occurs, loose or poor inter-connections. Since your battery was dead its always possible the power was left on for an indeterminate time, who knows?

apereira

So, if I let the power on, that culd cause the overheating to the point where the IC's were de-soldered?, and I should assume that a 6V battery with no regulator will never damage a servo even if its peak voltage reaches 7V?

Thanks for your help.

mglavin

My Feedback: (31)

If there was a load/restriction on the servos anything is possible (remember powered up without a signal from the TX the servos may have been bound up, causing them to be excessive current draw and subsequent heat damage). If your servos functioned when last used and later you noted the battery failed with some apparent problem with solder at the IC's possibly something shorted, maybe the battery. But then again why were only the three servos affected? It’s a tough call.

A fully charged unregulated 6.0V battery is NOT a problem...

apereira

So if the battery even at 7V after charging is not a problem, then that could be the explanation, I guess we did not thought about the fact the airplane has plug in wings and they were removed, so maybe thats what happened, accidentally when to on and without signal for the servos they overheated and burned, it was a PCM receiver but failsafe was only on throttle, of course, that servo survived.

Michael, thanks for your time and help, I will simply send the servos for repair, I love those servos and don't want to waste them.

Thanks again

Alejandro