Sherman Sound problems

[Michael McGaren]

Guys,

I am been having trouble again with the sound unit. I had this problem before, but after a couple of changes to where I put the wires and speaker I got it working, although I did have the problem a couple of times on and off. This time the engine startup sound restarts every time the turret moves and then is stopped. Before Mark thought that it was because I was using an antenna and that because it had a longer wire that it was weakening the RC signal by making the receiver antenna longer. I tried David Wards suggestion of using a separate 12V battery to isolate the circuit, but it didn't work. I have also soldered .1uF capacitors to the turret motor.

My Hitec Laser 6's receiver died on me (one day I couldn't turn left or right or use the sound) so I did go out and buy a new Spektrum DX7 2.4GHz RC system. I hooked it up and other than having to reverse a couple of servo functions to get the turret and gun to move the way I wanted them to it was working very well. All though once the start up sound did happen once, but I was moving the tank while moving the turret and then moved the gun up all at the same time.

It was working great until I did the following. I had been having a problem with the batteries. I have been charging them each separately, and after I unhooked the small blue wire that makes them 24V, I put one on the charger and it was at 90% charge. The other was at 8% charge. I asked Mark if the batteries should drain evenly and he said yes and thought the battery was bad. I took the one that was at 8% to the battery store where I bought it. They charged it up and did a test and said it was fine. What I did then was bring it home and then switch the position of the batteries to try it a different way (after fully charging both). Once I did that, the engine start up noise problem happened every time I start/stop the turret. Unhooking and switching the position of the batteries is the only thing that I did differently from before when the sounds did work. I did reverse where I put the supply side connectors and the blue wire that hooks them in series to make it easier to charge them as 24V (I did get a new 24V charger now), but why would that make a difference?

I do have the DX7’s receiver/s sitting on the sound unit, so I don’t think the signal is a problem because it wasn’t before I unhooked and switched the batteries. Yes I do have the DX7’s smaller second receiver 90deg and about 2â€

[Adrian Harris]

Couple of thoughts.

1) Does putting the batteries back to the pre-problem position resolve the issue ? If not, then it means that the problem is with something whcuh was disturbed by the battery move and not the move itself.

2) Does the receiver run from a battery and is that fully charged ? Only reason I ask is that the last time I had problems with the sound on my Sherman it was because the receiver battery was low - it seems the sound unit is fussy and noticed first.

Adrian.

[Michael McGaren]

Adrian,

I tried a few things, moving the batteries back, and moving some of the wires, but what finally worked for me is that I re-did the capacitors on the turret motor.

Before I used ceramic disc capacitors and I used some older resin core solder. I went and bought metalized film capacitors and used Silver Bearing type solder and did a better job of soldering. This seemed to do the trick, I hope.
Every time I move the turret and stop it I wonder if the problem will reappear, which really is a drag. Hopefully it will work from now on.

Thanks again for the help,
Mike