I was hoping Nightwing would have answered me here, but I will quote from that other board:
FYI...Got some new ideas
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Two thing to think on and could try
1) Could temporary flip xtals from the one that works over to the one that does not.
2) Use a nylon tunning wand to adjust the coil in the bit to reset its center receive frequency. Note slugh closser to coil lowers freq away raised freq.
There are some tool to help. One is a FSM or Field Strength Meter and another one is a sentitive Frequency meter. The first will tell you approx how much you are putting out and the 2nd shows you your transmit frequ. If too far apart could answer your problem.
Of all the thread and looking at the difference "sets" the only difference so far is the RF side. The actual controll is done by a TX2/RX2 chip set.
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OOPS sorry about that.
The xtal is the metal can with a number like in your case 49.xxx on it. Of the two its the simplest and easy one to put back. If it controls the car when you switch then you should be set. Either leave the xtal that works or replace the other and adjust the car.
The SKU for the tool set is 64-230a. Note that they usualy use wax or something to lock the slugh that you turn so it wont change freq when it hits something. Also its so small and easy to break.
The Field Strength meter can be made from parts from RS. It handy to see if a transmiter is really outputting and a measure how far it signal goes. Its simply a crude receiver that drive a analog meter.
The Freq is usualy purchase but sound like a one time item may just want to try the Xtal switch swap.
Need to make this note. Different mfg can wire the switched that feed that long chip inside the controller different ways. For example the 13 dollar RC from TRU control correctly Forward & Back on a ZZ car but steering is reversed. On other F & B are reversed. Others all are fliped. I think it comes out to 16 different ways to do it. With a simple DPDT switch can flip either F/B or L/R. Or with two switch both controles for anything.
There is one last thing that could help. There is a resistor that sets part of the internall osc on the IC marked TX2. On a ZZ its set with two resistors in line { 68k + 100k } on a Bit its around 220k with one. Oh one end is connected to pin 11 and the other to pin 12. Pin one has a mark next to it. Counting down and aroung so the pin on the other side of one is 14. You could pop one lead and temp jump lets say a 220 in place or a valur added to the others to get 220 or what ever is uses in the OEM controller.
Like this: ( top view )
01\ / 14
02| |13
03| | 12
04| | 11
05| | 10
06| | 09
07| | 08
Good luck!
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I'll give some of these a try, and report back.
FYI...maybe I could convince my wife that we need a sensitivity frequence meter to scan the house for bugs!
