Open Heart Surgery, Hitec 555/Electron6

[quantumMechanic]

A flying buddy of mine is suffering radio hits on his Hitec gear at our local flying field. My JR gear seems to be unaffected. I'm keen to try Mr.RC-CAMs idea of observing the output of the FM demod IC. Has anyone tried this with either a Hitec555 or Electron6?

I would appreciate any feedback before I get out the Scapel, soldering iron, signal tracer and perform some surgery. :D

qM

[vintage1]

No, but I hooked up some audio to a hitech feather..certainly enabled me to spot a bad tx xtal..

[quantumMechanic]

Thanks for the encouragement. Over the years I've learnt to trust my senses as much as a good test instrument.

Once I've identified the FM demod IC it shouldn't take too much probing around with a Hi Z amplifier to find the demodulated PPM.

I'll post my results.

qM

[SlopeKing]

The demod IC on the electron6 is quite hard to find, tis the one labeled 31136 on the bottom... havent worked with it myself, though i reckon a simple field strength meter should be able to be constructed using an LM3914 on the AGC/SigStr line... i have one for my HFS04MG...

[quantumMechanic]

Slopeking,
Is the device you targeted a TA31136 clone? If so I suspect I should be looking at AF out on pin 9.

For signal strenth I should target RSSI on pin 12.

Looks like I'll need my flying buddy to pull the receiver out and leave it with me for surgery before we go to the flying field.

qM

[vintage1]

pin nine is certainly where I got my audio from.

I have a hardwired on-my-channel radio that I can hear my trnny ion. And other rubbish when it happens.

[SlopeKing]

It probably wont have the same pinout as the TA7761 in the HFS04-MG and Mi+ but AGC was pin7 on that