Sorry to bother you again on a revived old thread. I successfully installed the TVS diode in my 6-18565 command control equipped GP-9. I also bought a 6-38312 F3. It is not command control equipped, but does have a circuit board or 2 inside for sounds. I figured out where to install the diode on that, and have done so, and it runs fine. The problem is the horn on the F3 only works about once every 5 times I click the whistle control, but the horn on the GP-9 is absolutely perfect. I have a fully refurbished ZW with the upgraded diodes, so that's not the problem.
The question to you is, would the TVS diode in the F3 cause the horn to function very sporadically? As I said, the horn in the more advanced GP-9 works fine.
