MFU and radio question

[Redronin]

Ok so yesterday I went and got an awsome deal on the 350 MFU by tamiya only to find out it works on like three radios .... so I did some searching and saw that the MFU works only with radios with analog trims and since I'm a poor college student and fall semester is bearing down on me I don't have a whole lot left to spend on a new radio..... I found that I have a eflite radio that is five channels and analog trims which would be perfect but my questions pertaining to it are:

Will it work with the MFU?
Can you modify a turn nob to a three position switch?

Its the LP5DSM model that comes with the cx2 helicopters thanks your help is much appreciated!

[benoj]

if you plan on using the control module from the heli for a reciever no it wont work i just tried it and you only have 3 channels that work for it. the 2 on the right stick and the ch 5 knob. the other stick controls the 2 motors on the heli ( throttle and changing direction of motors for spinning)

[Redronin]

Actually no I will be using the AR6100e reciver from spectrum that comes with the newer cx2

[benoj]

well your best bet is to just try it and see

[microgoat]

There's a lot of mixing going on in the CX, and I don't know if it happens in the transmitter or elsewhere.

Plug it in & see what happens.

[Redronin]

It works!!!!!!!!!!!!!! but there are some things that don't..... lol the turn signals don't wink.... When I was going thru the "learning" mode the trim learning mode kept failing. but im not sure what modes the mfu is suppose to be in for any of the training modes. (the book doesnt say) but other than the turn signals everything else works awesome!!!!

now I need to be able to change the ch. 5 dial to a three position switch

[clockworks]

Originally Posted by Redronin

It works!!!!!!!!!!!!!! but there are some things that don't..... lol the turn signals don't wink.... When I was going thru the "learning" mode the trim learning mode kept failing. but im not sure what modes the mfu is suppose to be in for any of the training modes. (the book doesnt say) but other than the turn signals everything else works awesome!!!!

now I need to be able to change the ch. 5 dial to a three position switch

You should be able to mod Ch5 the same as with most other Txs, using a SPDT on-off-on switch and 4 resistors - 2x 2K2 and 2x 220R.

Remove the left and right wires from the pot, soldering each of them to one end of a 2K2 resistor. Solder the other ends of both resistors to the centre terminal of the switch.
Remove the middle wire from the pot and solder it to the centre terminal of the switch.

Solder one end of a 220R resistor to each of the outside switch terminals. Solder the other end one resistor to the positive wire you removed earlier (where it joins to the 2K2 resistor), and the other resistor to the negative wire.

[Redronin]

ok cool but i have a question.... why so many resistors? im no electrician need some explaining.....

[clockworks]

Originally Posted by Redronin

ok cool but i have a question.... why so many resistors? im no electrician need some explaining.....

The 2x 2K2 resistors simulate the pot being in the centre position - they are absolutely necessary if you want 3 positions.

The 2x 220R resistors simulate the pot being at either end. When the original stick is at full throw, the pot doesn't go right to the end of it's travel.
You could probably get away with leaving these off, but it's bad practice to tie a signal or logic line (the middle wire from the pot, in this case) directly to ground or +ve. The 220R resistors are basically a safety measure in case something goes wrong with the switch or the wiring - stops you shorting +ve to ground.

You can achieve the same thing with just one 220R resistor, but it's more complicated to explain!
Besides, resistors cost pennies - literally.

The actual values aren't important, as long as the 2 main resistors are the same value, and the 2 other resistors are lower value than the main ones.
You can fine-tune the full throw of the servo by changing the 220R resistors - useful when you haven't got EPA adjustments on the Tx.
Even better, use a couple of 1K trim pots instead of resistors, then you have built-in EPA.

[Happy_trucker]

Originally Posted by Redronin

It works!!!!!!!!!!!!!! but there are some things that don't..... lol the turn signals don't wink.... When I was going thru the "learning" mode the trim learning mode kept failing. but im not sure what modes the mfu is suppose to be in for any of the training modes. (the book doesnt say) but other than the turn signals everything else works awesome!!!!

now I need to be able to change the ch. 5 dial to a three position switch

I guess you are talking about the MFCs right? I use a RDS8000 which is digital and it works also. Read the direction really careful. The MFC for the pickup trucks are tricky compared to the older one on the haulers. I have both new and old, for the new turn signals to work, you have to clutch in 100%( basically pull the right stick down) and then release then the turn signals should work, if you do that again, it will cancel your turn signals. Something like that and make sure your trim are nuetral(#7 on pg 11&12 on the manual)

[Redronin]

well when i go through the training mode i put the trims on the right stick all the way to the right and up like it says then turn the unit on and wait till im suppose to, to put the stick to the upper right corner... but then it makes the motor sound and horn go... which means the training failed :?