Futaba t4vf skysport4 tx / fp-r115f rx

Might anyone on here has a service manual/test procedure/test info on this combo please ?

My friend mo said it did work as he was using it on an rc car, naughty boy!

Crystals same, 66. Marked tx and Rx.

Tx signal spot on as seen on scope, but when sticks twiddled I cannot see any "movement" or change.
I would have thought that something would be seen.

The Rx aerial wire seems ok, continuity from end to circuit board.

Tx on, tx output gauge shows 100percent, Rx powered up ( servo movement on power up ) but no servo response when sticks twiddled.

Anyone have a test procedure/expected results/scope traces/schematics for this combo please.

I know of manualslib but not fully investigated there yet.

May enquire with ripmax but they were hopeless with last enquiry.

Is it tx problem or Rx problem...

Any/all help greatly appreciated.

rich

Hi Eric, it's a 35 meg set and both crystal 66 marked tx and Rx appear to be Futaba.

The tx meter is marked "output"...
Will have a go at the "listening" test technique...

Would be good to get this set working, I have no similar set for substitution test.

The challenger has a dual conversion Rx...

I would have thought that something would be seen to change on the scope when the tx sticks are twiddled, nothing was seen, just a rock solid and spot on carrier wave...

Yes, looking at RF out, but would not the "message" be mixed, superimposed with the carrier wave, and seen ?

Will have an other go later...

Rich
You mentioned dual conversion. If the rx is dual conversion the crystals have to be dual conversion and a matched pair. Dual conversion use a second frequency that is selected by the manufacturer. A single conversion crystal will not work with a dual rx.
Single conversion crystals can be 'mixed & matched' between manufacturers. I do on my 35 meg Skysport.

Thanks for that, I didn't really want to put the challenger crystals into the skysport4 just in case it buggered them.

Would you have any tech info on the skysport4 ?

What kneck of the woods do you live in ?

I need to establish if the Rx works, how would you feel about...if I sent the Rx to you with a prepaid padded envelope for its return, if you could put your Rx crystal in it and see if your tx will work it ?

This would establish if the Rx works...

Without a test procedure I am in the dark...

There is no rush on this...

I have contacted ripmax Futaba for help/info but i am not holding my breath...

I have found an other possible source of info for Futaba but they are a USA based web address...

Rich
You can download a Skysport 4 user manual here for free. It is all pretty basic.

Not quite sure about fp-r115f as these are the numbers for a 5 ch Futaba transmitter.

You can certainly send me your rx and I will test it. I will pm you my address.

I note there is a Futaba SKYSPORT T4VF for sale on Ebay £12.99 + £4.50 postage. It might be easier to use that than to fix a fault.

I must make notes where is see)read stuff, print outs would be good, saves those oh so common ( for me ) moments of " wtf did I see that on the dam nternet !".

I have seen a Futaba instruction sheet somewhere that lists comparable Futaba RX's, the r115f being one of them.

Now your getting technical, resister and diode, to drop output and demodulate ?

Will be checking challenger output to see for any changes, if changes seen when twiddling the sticks and that set works ( no t tested yet, roof repair before it rains again ) will try the skysport4 again.

Yet to do "listening" test with radio...

This set is a bit redundant as it don't work ( yet ) so is on the back burner...

But thanks for your help and input, much appreciated.

It's Moe's set, left to him with lots of other stuff by his late uncle. His family had a trajic years last year, lost three family members, not to covid...

Thanks quorneng, that's the one...

Must get roof done before w before it rains...