Diablo-RCU

My Feedback: (1)

I have a Futaba transmitter T8UAPS that I have been using for years on multiple planes without any problems. Recently, the transmitter has quit transmitting a signal intermittently. I've caught the problem about 4 times on the ground before a flight and once in the air. I know it's the transmitter because the problem has has happened with two different planes. I have been lucky and haven't crashed a plane.....yet. When the transmitter stops putting out a signal, the PCM receiver goes into it's failsafe setting. The transmitter does not lose power and the screen stays lit up. I've opend the transmitter up and checked to make sure the antenae wire is still attached, and I don't see any broken wires or cracked solder joints. Is this a known problem with this model of transmitter? Do you think it can be repaired? Does it have to show the problem continuously before you can find the problem and repair it? I'm suspicious it may be caused by heat (sitting in the sun), but this is only a guess. The last time it quit working, it had been sitting in the sun. Took it apart in the shade, found nothing wrong, put it back together and it worked fine. Shaking the transmitter does not effect the problem.

If the transmitter can't be repaired, which other Futaba transmitters are compatible with the Campac in my T8UAPS. I'd like to transfer my model data to a different transmitter.

karolh

I have one too and I'm interested to know.

Karol

Bax

My Feedback: (11)

Early versions of the Futaba 8U transmitter could have the solder joints break on the pins that connect the frequency module to the transmitter. If that's your transmitter's difficulty, it's easily repaired with a bit of solder and some reinforcement.

Of course, it could also be something else. We'd need to see it. Just send the transmitter to us.

Bax

My Feedback: (11)

Early versions of the Futaba 8U transmitter could have the solder joints break on the pins that connect the frequency module to the transmitter. If that's your transmitter's difficulty, it's easily repaired with a bit of solder and some reinforcement.

Of course, it could also be something else. We'd need to see it. Just send the transmitter to us.

billhass

My Feedback: (1)

First , make sure your receiver battery is good. When the failsafe is and the receiver battery is to low it will activate the failsafe.
I had this problem and it was a low battery charge.
I also had a range problem and sent it to Radio South and they found a shorted4.7uf choke.
They say this is not uncomon for this transmitter as it gets older.

Diablo-RCU

My Feedback: (1)

I checked the pins for the module connection with a continuity tester, and one of them would lose continuity by wiggling. So, I desoldered and resoldered all the pins. The transmitter now works, but I'll do some more ground testing to make sure it works all the time. Thanks BAX and all for suggestions. If it continues to have problems, I will send it in for repairs.

kpblau

My Feedback: (30)

I own a FP-5UAP.  It sat totally unused in the original box for about 25 years and I started to use it this summer for the first time.  After about 10 flights I dumped my trainer for what seemed to be loss of radio control.  Then this weekend, I lost control of my plane on takeoff.  There is a similar problem as described for the T8UAPS above.  Just twice in the pits we saw that the signal from the transmitter seemed to die when the antenna was turned.  I removed the antenna and cleaned it thoroughly, but I'm afraid to fly.  I've always fully extended my antenna, and the battery meter read fine at all times.
Do you think that a dirty antenna was the cause, or did you also have intermittent solder joint problems on my model transmitter?
Thanks,
Ken      

Bax

My Feedback: (11)

We'd not be sure about the 5U. It had been discontinued for several years when we became service for Futaba in North America. We've never seen many of those, and they are now on our non-serviceable list. You may want to check the pins for the module. It just takes a few moments to pop off the rear cover and look at the board where the modules plug in.

kpblau

My Feedback: (30)

Bax,
Thank you for getting back so quickly.  I wasn't sure you'd see my post.  I'll take a look tonight.  I was concentrating on the antenna connections and the fact that the antenna is not hard-wired to the circuit board.  It's only a pressure-fit sliding connector.
Ken