Basic Tx & RX matching question

[Nigel Day]

I bought a basic Futaba kit for my first foray into R/C (SS3 I think) a few years ago.

Having finally got around to building the model (Junior 60), I figured I'd get a simulator to help me learn to fly (as a prelude to getting help within a club of course). That necessitated the purchase of a suitable Tx so I bought a second-hand T6EXA.

The Rx that came with the original set was an R114F and works just fine with the SS3(?) Tx.

I'd like to get the 6EXA working with the receiver now. There's no response from the servos with the 6EXA whilst the SS3 does operate them via the Rx. The SS3 isn't configurable at all and the throw it passes to the servos is limited.

From the little I've picked up so far, I suspect that I need to change one or both of the crystals in the Rx and Tx?

Is that correct? If so, How do I so that? I can't see anywhere obvious on the TX and haven't looked closely at the Rx lately. I don't recall seeing any info in the 6EXA manual either.

Any help would be much appreciated.

Thanks in advance.

[Paul Marsh]

You need to make sure that the tx and rx xtals are the same frequency. The radio that I sold you was used the week before on ch .78 and we need to know what frequency the R114 is on. Is it 35mhz. or 40mhz?

[Andrew767]

Nigel ....the crystal holder on the 6EX is at the back. Sorry don't know where it is on the SS3...a quick google perhaps??.....if you can get the crystal from the SS3 to the 6EX should do the trick as we know it matched the Rx.

Andrew

[Andrew767]

Posted by Paul Marsh on 09/12/2013 20:26:57:

You need to make sure that the tx and rx xtals are the same frequency. The radio that I sold you was used the week before on ch .78 and we need to know what frequency the R114 is on. Is it 35mhz. or 40mhz?

Ah!...sorry...didn't think about the SS3 being 40mhz.

Andrew

[Simon Chaddock]

First is all your Futaba gear on 35mHz?

For a Tx to work an Rx it must have the matching frequency (and type) of crystal.

The crystal has a tag on it with the frequency channel printed on it.

Tx and Rx crystals are specific but must have the same channel number.

So the easiest solution is to remove the crystal from the ss3 (its on the front) and use it in the 6EXA (It goes in the back)

As both are Futaba FM type transmitters it should work fine.

I hope this helps

[John Privett]

Nigel, looking at the manual for the SS3, the receiver crystal plugs in to the end of the R114F beside the aerial. The crystal should have a little tag on the end with which you can pull it out. Let us know what numbers /words it has on it.

It looks like the SS3 transmitter crystal is under a little cover on the front of the SS3 tx near the bottom left-hand corner.

However, that's just judging from the appearance, as it's the American manual, and it doesn't mention the transmitter crystal at all - bizzarely it is technically illegal to replace the crystal in the USA without being qualifed... "Go figure" , as they say over there!

[Nigel Day]

Many thanks all.

After I'd posted I had another read of the 6EXA manual and a better look over both sets.

I figured what must be the crystal (in holder) on the SS3 and removed it.

What stumped me at first was that couldn't see anything that looked like a crystal(holder) on the 6EXA. Then I looked at the 'disabled' SS3 and saw the hole. There was a very similar on the 6EXA.

I hadn't noticed the lack of crystal as I was only using the 6EXA attached to a flight sim.

Sure enough, as soon as I fitted the crystal from the SS3, all was hunky dory. Well, almost.

The battery level on the 6EXA then took a nose dive from showing 96-97v down to 89v and quickly down to 84v where it started to complain. I removed the crystal and now it's showing about 92v. Enough for me to learn a bit more on the flight sim but meaning that I need to accelerate my search for a charger for the 6EXA.

Since I'm not ready for my first electric set up yet (2-3 months away), I'm just going to get a simple charger. I've seen chargers for the 6J available (with adapter for a Tx). Does this fit and charge the 6EXA too or do I need something else?

Thanks again,

Nigel

[Rob Jones 2]

I have used the same Futaba charger for 30 years= it is the blue one in the middle costing £15.50:**LINK**

[Rob Jones 2]

The batteries in my Futaba challenger were the same all those years ago as in my computerised 7c now (NiCad).

When you come to need a charger for flight lipos, you can get a balance charger that plugs directly into the mains, they also cost about £15.Model shops may try to sell you all sorts of balancing gizmos, but you don't NEED them. As a very occasional flyer I use an Imax C3 to charge my lipos prior to a flying session.

[Rob Jones 2]

This is the one:**LINK**

[Nigel Day]

Thanks Rob.

Looks as though that's the one I need.

Shame there's a UK-wide shortage though.

[Rob Jones 2]

Very likely someone here has a spare one.

[Nigel Day]

Good idea Rob, I'll post in the 'wanted' section.