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#1 delwinnikolov Jan 25, 2013 05:14 AM

Damaged Futaba 6EX TX
 
Hello all,
I've made a stupid thing reversing the battery polarity (by mistake) of my 6EX transmitter. Now the TX module seems dead, no leds and no TX, only the LCD is working and the controls. Anybody knows how could I repair it?

#2 delwinnikolov Jan 26, 2013 08:55 AM

repaired
 
Hi there, I'm glad to report that the radio is repaired. For anybody with this problem, dead(6EX) TX after reverse polarity, check the voltage regulator on the TX board, it is a SMD 7805, replacing it solved the problem.

#3 RC Man Jan 26, 2013 10:11 AM

The older Futaba radios had a diode to prevent that from happening. I don’t know why they have left out that on the newer radios.

.

#4 pilotpete2 Jan 26, 2013 11:06 AM

If I'm not mistaken, the diode in the entry level Futaba's was in the charge jack circuit to prevent reverse charging the Tx battery. More expensive Futaba's use a PolySwitch circuit breaker instead of the diode. I'm pretty sure that if you connect the battery to the radio with reverse polarity, there's no protection against that:o
Futaba's use of a standard servo plug for the Tx battery does make that very hard to do. You really have to wire the connector backwards to let out the magic smoke:o

delwinnikolov,
Nice to hear you have it fixed:)
Pete

#5 A.T. Jan 26, 2013 02:09 PM

Quote:

Originally Posted by delwinnikolov (Post 23935937)
Hi there, I'm glad to report that the radio is repaired. For anybody with this problem, dead(6EX) TX after reverse polarity, check the voltage regulator on the TX board, it is a SMD 7805, replacing it solved the problem.

Thank you, any similarity to the photos and information shown:
Futaba - T6A - Reverse Polarity DIY repair.
"the element that had burned was a power regulator, the equivalent one LM78L05 "

Alan T.
Alan's Hobby, Model & RC FAQ Web Links


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