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Old Aug 11, 2006, 04:04 PM
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Old Futaba FP-T7FG/E gold radio

I have an ol Futaba FP-T7FG/E gold radio perfectly working and would like to give to my son for beginning flying, the only problem is that the receiver is really weighty for a little 2D depron model I have built for him. Any advice on which type of receiver can I use instead of the original one?
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Old Aug 11, 2006, 04:13 PM
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I have the FG and FG/K... The FG is AM.. it runs any of the Futaba AM receivers I have. The FG/K is FM, and runs any of the FM receivers.
The Fut 114H is a small AM, suitable for a small plane,
while the Hitec 05 is a good FM receiver.
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Old Aug 11, 2006, 04:22 PM
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[QUOTE=Sparky Paul]I have the FG and FG/K... The FG is AM.. it runs any of the Futaba AM receivers I have. The FG/K is FM, and runs any of the FM receivers.
The Fut 114H is a small AM, suitable for a small plane,
while the Hitec 05 is a good FM receiver.[/QUOTE
Hallo SPARKY my is a FP-T7FG/E gold FM modulation on 72 MHz!
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Old Aug 11, 2006, 05:13 PM
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The FG/E was a gold box with exponentials while the FG/K was with dual rates. If it has a FM module, any negative shift receiver will do.

BTW those are classic radios; I had a 7 FG/K as my main radio from 1983 until late nineties. And It's still alive but rarely used.

Harri
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Old Aug 11, 2006, 05:18 PM
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Ah... forgot to say that the old Futabas had a center pulse around 1,3ms while the current standard is 1,5ms. In worst case some DSP receivers might not work due to unnormal pulse. So a receiver without DSP might be a best choice.

Harri
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Old Aug 11, 2006, 06:14 PM
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Quote:
Originally Posted by Harri Pihl
Ah... forgot to say that the old Futabas had a center pulse around 1,3ms while the current standard is 1,5ms. In worst case some DSP receivers might not work due to unnormal pulse. So a receiver without DSP might be a best choice.

Harri
.
All I've noticed is the servo neutral is different between the FGs and today's radios.
Resetting the arms on the servos fixes that.
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Old Aug 11, 2006, 06:18 PM
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If its the FM version... The GWS 4p(F) or Blue Arrow 5 ch RX's will work with it. (for LIGHT RX's)

they came in FM and AM versions on 72 mhz. You will want to verify that its on a currently legal frequency (I had one on 72.080 which is now illegal for RC)

FM version should pass narrow band tests. Should have the RCMA gold sticker on it from being checked anyway. From my reading of the FCC code... if it has not already been checked and updated (if needed) the "window" for doing it is over. May want to verify that though.

Harri's post may point to what they did to mine when I had it updated... they did something to the FM TX... and sent the replacement RX. May be they realigned the pulse center value. Its been 17 years...
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Old Aug 11, 2006, 07:05 PM
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My radio frequency is on 72.320 I think that changing crystal may solve for legal frequency...
Thank you to everyone for helping.
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Old Aug 11, 2006, 09:00 PM
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Well.. crystal changing is probably legal where you are... (just noted that you are not in the US, so some of the above FCC stuff doesn't apply. The 5542 mi should have been a clue.....)

Its a good idea to have the tuning checked whenever you change crystals. Plus a radio that old... it wouldn't hurt to have inspected for internal corrosion and such. Make sure that you use a compatible crystal. You can't just assume that it saying its for an FM TX means it will give the results you want.
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Old Aug 12, 2006, 02:56 AM
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The center pulse can be changed with the aid of scope. My FG/K tended to freeze Schulze 440 (quite same as old 4ch Berg Microstamp) if one of the channels got too low pulse. I plugged the receiver to one of those sound card based scopes and after some "trial and error" found right potentiometers. Then I just adjusted these until I got 1,5ms center and +- 0,5 ms max movement. It was quite difficult to adjust exactly because the both potentimeters had effect on other but in the end I got it working well.

Note that I was adjusting just the coder, not the module. So don't do this if you don't know what you are doing. Any R/C repair shop can probably do this easily and legally I suppose.

Harri
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Old Aug 12, 2006, 04:20 AM
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[QUOTE]I plugged the receiver to one of those sound card based scopes and after some "trial and error" found right potentiometers. Then I just adjusted these until I got 1,5ms center and +- 0,5 ms max movement.

I did the almost same thing waaay back when! - except I only adjusted one pot labeled "PW" (pulse width?) on the encoder board until neutral was 1.5ms. I guess the next pot to the right labeled "FR" (frame?) adjusted the end points, but they seemed OK to me at the time! Mine is an AM with no module opening in the back, but the RF board easily unplugs and the RF board from one of the somewhat later FM modules will plug right in its place when removed from its little plastic "box". Good Lift!
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Old Aug 12, 2006, 05:55 PM
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Yep, I did that couple years ago and looking the boards (I have two FG boxes here) the potentiometers were probably those labeled PW and FR. Mine FGs are those early style gold boxes with rather large pcb. Later FGs had a different coder board and I don't know if these could be adjusted same way. At least boards with the 5044 and 4017 chips are quite easy to adjust but I don't know if Futaba used these.

Harri
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Last edited by Harri Pihl; Aug 12, 2006 at 05:57 PM. Reason: typing errors
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Old Jan 21, 2011, 08:40 AM
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Where does the battery plug in?

I have a couple of old Futaba FP-T7FG/E gold radios that do not have batteries in them. I am wanting to test/check these radios out but I am not sure where the battery connects. I have taken them apart and found 2 male pins on the back of the circuit board and traced the wiring from the charger port thru the power switch and it seems these are infact where the battery plucs in, but I would like to know for sure before U burn somthing up. Can anyone tell me for sure if this is correct? Thanks.
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Old Jan 21, 2011, 09:26 AM
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Futaba Gold series transmitters have the same RF module connectors as newer Futaba radios (the RF module opening is a bit larger, but it can be filled with pieces of foam around the modern module). I have replaced the original AM module with the new FM module and it worked with an FM receiver, 6-ch Corona in my case. I bet you can also stick a 2.4GHz module there. "Old dog" can indeed learn new tricks!

Boris
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Old Jan 21, 2011, 02:22 PM
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Quote:
Originally Posted by Carl Webster View Post
I have a couple of old Futaba FP-T7FG/E gold radios that do not have batteries in them. I am wanting to test/check these radios out but I am not sure where the battery connects. I have taken them apart and found 2 male pins on the back of the circuit board and traced the wiring from the charger port thru the power switch and it seems these are infact where the battery plucs in, but I would like to know for sure before U burn somthing up. Can anyone tell me for sure if this is correct? Thanks.
That's correct, it's a white connector with a lip near the fuse.
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