Mac_Man_UK

Hi Danny,

Have been given the following headache, perhaps you can shed some light on it for me. The following has been condensed from another forum which I assist one.


" The problem has occured with two helis, the heli locks out but does not go into failsafe. Hold switch does not work during this time so you cannot cut the power. On the bench the failsafe works and so does the hold switch. Both heli's were flown using the same transmitter. The transmitter is a PCM 9x (9303) the two receivers are 9 ch pcm both using heavy duty JR switches both using Sub C NIMH packs both on different helis I have checked everything and all seams good

Both rx batteries had good power. After the crash everything worked fine. In all our heli's we use sub c packs so no regulators ,
All the switches are heavy duty and all check out fine, Also one of the helis had cf boom supports and the other ali.

All failsafes set to idle

Range check on both models with the original crystals and both with the antenna fully collapsed and got a range of over 100 yrds. Even tried tapping the tx and rx crystal with no change "

Have thought about the paths in the 9X (9303) but the above fault doesnt make any sense for it to be the Tx. If at the Heli end, what would cause 2 different installations to exhibit the same fault ? Again it points to the Tx !

Have you or your bunch of merry men come across anything like this ??

Looking forward to your suggestions,

dsnyder

The only way I know of that to happen is if when using a PCM system, and the channels are set to hold and not to fail safe. In that event they would hold last position and not move. If fail safe was set however and did not return to the stored position, I'm not sure how that could happen.

Mac_Man_UK

That was my first thought ie failsafe set to hold, but the guy tells me that the throttle was set to idle, plus it behaved when on the bench.

This has me completely at a loss to explain.

dsnyder

Ya, same here. I haven't seen that ever happen. It is possible for a stray signal to be "coded" correctly such that the receiver accepts and uses the data, and can cause very odd behavior like that, only that is HIGHLY unlikely.

andythepipe

Hi Mac Man, I have had a similar problem to yours with a PCM10, on PCM, flying a Acro Wot. Had minor glitching, landed, checked out the model, could not find any problems (motor not running) , so took off and about 5 seconds later had a complete lack of control (the only difference was throttle went to failsafe), model was free fight for about 30sec, landing in a hedge with minor damage. Recovered the model, checked radio, all working, normal range, no glitching etc. Tested on the bench, all fine.

But on further investigation, on stripping cover from receiver battery pack, I found a failed battery weld. I believe problem was a lost/ partial lost of battery continuity and was related to vibration from the motor. This may not be the same problem (two set ups), but heli do suffer from high levels of vibration.

Andy.

Mac_Man_UK

Thanks Andy, I never really thought of the battery packs (especially 2 of them). It would be unusual for it to happen on 2 seperate installs but not impossible. I'll pass that back and see what the outcome is.