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Frequency Change on Futaba Receiver R138DP (PCM) originally tuned for 72Mhz Answered

Futaba has discontinued their 50Mhz receiver Model R138DP, however its available
in frequency range 72Mhz.  I have Futaba Transmitter 9-Cap operating on 50Mhz. I want
to convert all my 72Mhz receivers to 50Mhz since there is nobody using 50Mhz in our
model club so no chance of Frequency Clash, more over I experience Glitches on 72Mhz
but non on 50Mhz. 



8 years ago

It can be done but you don't have the knowledge or the equipment to do it.

It's not just a case of change the crystal and make it work. 22mhz is just too much of a change.

There are coils and internal crystals that have to be changed for it to work. Some of the transistors might have to be changed to operate properly. Then after you have it all changed you have to align the receiver for optimum power.

See if you can find some rec. on ebay or some of the sellout shops.  OR try another model receiver.

Zahid H KhanRe-design

Answer 8 years ago

Thanks Re-Design., Well I have Television Assembling Factory and also have skilled technicians too. We have the capability of re-work on SMD Pcbs so changing the parts would be no problem, however availability of the correct parts is a question mark. Would you have any information where I can get the schematic drawing (Circuit Drawings ) which will make it easy for us to understand and do the correct and precise changes. Well in case not going through the hassle and buying a new Radio / Transmitter I prefer to go with 2.4Ghz to address all the interference problems once for all.

Re-designZahid H Khan

Answer 8 years ago

I do not know which parts you would need to change. I've converted shortwave radios to other freq's before but never an R/C radio.

I doubt that you can get a schematic for the radio since Futaba wouldn't want anyone copying their radio.

If you have a TV assembling factory then there probably is a signal generator that you can use. It needs to work in the range of 50-72 mhz. If so then hook it up and change the crystal to the new freq. you want to use. Then there should be some adjustable coils. Adjust those to see how close you can get to the new freq. Now there should be some other coils that are unadjustable. I would try replacing them with larger coils since you are trying to go down in freq. You also need an o-scope to read the output. You can't use a servo since the output may be very small until you get the exact parts and align it.

There should be some capacitors connected across the coils. It may help to replace them with larger caps.

Good luck.

P.S. If you have skilled TV techs then they probably already have the know how to do this project. I just don't see the point of hacking receivers and not knowing the reliability then putting them in expensive R/C.