They do have a way of liking the use of different encoders... the T4VF uses an FP6335 encoder, the T4YF uses an FP6347 and it turns out that the T6YF uses an FP6324... all of which are different and not only in their number.

Thanks anyway

Originally Posted by Epitaph

pins 1, 2, 4 and 5 are also a channel each, and it turns out that the 5th channel pad that comes ready on the 4YF is connected to all 4 of these, and from what I can see, only these 4.

Does this mean it's as simple as seperating pins 1, 2, 4 and 5 and putting them as independant each one to a switch? or is it more complex than that?

Does your board look like the picture below?

If so then I suspect that channel 5 is supposed to be connected to all of those pins, and is biased to center with resistors R38 and R39. To (hopefully) activate the 5th channel, connect a pot to W/R/B, remove R38/R39, and short J19.

If this works then check channels 6~8 on the receiver. If they also respond then you could try separating pins 2/4/5 (channels 6/7/5?) and attaching individual pots or switches to them.

yep, that's how it looks, except it says ST5 instead of WRB. It already has a resistor on J19 from factory. The 3 pads are the +5, gnd and signal for a 5th channel, and is connected to pins 1,2,4 and 5 of the chip. I tried seperating the 4 pins from each other by cutting the line on the PCB, and channel 5 still works the same as usual, but still nothing from channel 6, 7 or 8 (pins 2, 4 and 5) when I bridge these individually to ground. I've tried both with a 6 channel reciever I have (I don't have any 7 channel ones yet) and also with the simulator cable using the Windows Joystick configurator, which the cable is prepared for a 10 channel radio and Windows recognises all 10 channels. BTW, everywhere where it says about activating the 5th channel it says nothing about removing R38 and R39... and I have the 5th channel already working from ages ago. I was looking for the 6th and 7th (and maybe 8th, as the multiplexor is supposed to be an 8 to 1) channels

I read that it might have something to do with the A, B and C conections (pins 6, 7 and 8) that have to be changed... but I don't know about that. In the T4EXA it has a very similar configuration, and in that radio the 5th channel is taken from the display CMOS rather than from the 4051 multiplexor. Maybe a 6th proportional channel can be activated on the T4EXA by using the T4YF 4051 configuration...

Most radios that have the 4051 it turns out they only use it to mix the 4 "main" channels (all of which of course are proportional), and that all the other channels come from the main chip (which on the T4YF it's on the other side and is a FP6347, which I can't find any other radio that has this chip. The T4VF can use he 5044, or it can use an FP6335, and a multiplexor 4051 for the mixing of the first 4 channels, and that the other 3 channels come straight from the FP6335. I've been trying to find a datasheet or a pinout for the FP6347 to figure out the conections to use based on the FP6335 configuration for channels 5, 6 and 7, but no luck finding anything)

Originally Posted by Epitaph

It already has a resistor on J19 from factory.

What is the value of that resistor?

The 3 pads are the +5, gnd and signal for a 5th channel, and is connected to pins 1,2,4 and 5 of the chip. I tried separating the 4 pins from each other... but still nothing from channel 6, 7 or 8

As I suspected, the FP6347 is only polling the first 5 inputs of the multiplexer.

BTW, everywhere where it says about activating the 5th channel it says nothing about removing R38 and R39

It will still work with the resistors in, but it will have some 'built-in' negative expo.

I was looking for the 6th and 7th (and maybe 8th, as the multiplexor is supposed to be an 8 to 1) channels

Unfortunately it seems that the FP6347 is only programmed to accept 5 channels. This explains why the 6 channel radios use a different chip.

You can still add more channels, but you will need another chip to do it. I have developed a circuit which adds 2 extra channels to a 4, 5, or 6 channel radio.

Originally Posted by Bruce Abbott

What is the value of that resistor?

I don't know... I don't have a multimeter here. Sorry

Originally Posted by Bruce Abbott

As I suspected, the FP6347 is only polling the first 5 inputs of the multiplexer.

Really that would be the ideal thing, to find out how to activate the other 3 channels on the multiplexor, and from fragments here and there, I'm sure it has to do with the A,B and C part of it (Remember, I don't know electronics, I only know how to solder!)

Originally Posted by Bruce Abbott

It will still work with the resistors in, but it will have some 'built-in' negative expo.

I noticed this with channel 3. When you use the stick (on Windows joystick) you see the slider change on the throttle bars (one negative, one positive). But when you bridge the signal directly to GND, it kind of "goes over" those limits, and lights up button 1 too (fifth channel controls button 2 (6 in total) and a slider bar for proportional)

Originally Posted by Bruce Abbott

Unfortunately it seems that the FP6347 is only programmed to accept 5 channels. This explains why the 6 channel radios use a different chip.

I find this a little strange, that they would bring out the T4VF with a 7 channel chip and the T4YF which is the one that carried on in production with only a 5 channel chip. But everyone that has seen the T4YF with an osciloscope has said there are 8 channels on it, and the multiplexor is only handling 5, so where are the other 3 coming from? Also, supposedly (from what I can understand), the chip isn't actually handling 5 channels, but rather the multiplexor is mixing those 5 for the chip to handle. It's only handling really 1 input by itself because the 4051 is doing all the work, unlike in the case of the FP6335, which handles 4 inputs, one of which has 4 channels mixed togeather with the same multiplexor, and when you expand channels on the T4VF you actually take them from the FP6335.

Originally Posted by Bruce Abbott

You can still add more channels, but you will need another chip to do it. I have developed a circuit which adds 2 extra channels to a 4, 5, or 6 channel radio.

Thanks, but I think I'll have to maybe get into that a little further down the road if I decide to go back to the project, as I said, I don't know electronics, and all the programming part is very much beyond me. This module would make the T4YF a bit like the older european Robbe-Futaba (like the F-14 and F-16) or Multiplex (like the Europa) transmitters where you add modules to expand channels.