FrSky issues recommended "fix" for DIY kit

[RCModelReviews]

Yep, Tommy's right. The diode is a one-way-street for the flow of electricity so it will allow the transmitter circuit to "suck down" the voltage on the module input but won't allow that voltage to go any higher than the 3V the module uses.

The schottky diode goes in series with the signal to block current from flowing in one direction (from the transmitter to the module where excessive voltage could damage stuff).

A Zener diode effectively does nothing until the voltage across it exceeds the rated voltage -- then it begins to conduct excessive voltage. You could use a zener between the PPM in put and ground but that's not the best solution for a number of reasons -- not the least of which because it would also require an extra resistor to avoid the excess current which might flow from overheating the zener.

So the Shottky diode is like a one-way valve and the zener is like a bypass valve.

[erezra]

I see,

Thanks for the clarification!

[tommy]

How about the Jerky servo movement with the frsky module. I have seen that the two way system (Telemetry) has a ROM upgrade which may solve this problem.
Can this solution also be applied to the DIY module. ??

This jerky problem is concerning me because I have a fast digital servo and GYRO for my Heli my heli.
Having a jerky tail on a heli is BAD...

I think I am starting to regret buying frsky. Time will tell. The fact that I have had to go back to 35MHZ because of these issues is starting to annoy me

[crash]

$1.20 got my diode and installed my self in the hack module. Did not bother contacting the Aussie distributor as I thought as he knows my address and that I bought a hack module, he may have sent me one.
But alas no. so all fixed, hope it works well on my Graupner MC 24.

Thanks for the update

cheers

Crash

[tommy]

I will be doing the diode fix as well but then there is the jerky servo movement problem. I hope the ROM upgrade for the Telemetry system will also work for the DIY.
Looks like you will need to update both the tx and rx. I have a horrible feeling that you will not be able to do the ROM update on the DIY. Let’s wait and see.

[RCModelReviews]

If you've still got a problem with the DIY module, try contacting FrSky directly. Their customer support has (by all reports) been extremely good. I'm sure they'll ensure you get a resolution (no pun intended) to your problem.

[tommy]

Thanks I may try that. Do you know if the ROM upgrade can be done on the DIY module ?
It's a shame that these problems have come up because the frsky seems to be a very good system.
I actually haven't had any issues with the frsky DIY besides noticing a very slight jerky servo movement.
I probably wouldn't have given it much notice if it wasn't for what I have read in the many forums.
A jerky servo on a heli tail is not good so I would rather be safe than sorry.
As you mentioned, it does seem like frsky are trying hard to resolve these issues.

[tommy]

Great. After some more research looks like the ROM upgrade cannot be done on the DIY module.
Hence I cannot have a jerky servo on the tail of my heli.
Looks like I have just wasted money and a lot of time on the frsky module.
Not to mentioned all the mods I have done to my transmitter to get the module installed.....

[BlueSkyRoro]

Corona made the same mistake!

Hallo Bruce, hallo Everybody,

I'm using a Graupner/JR MC-16/20 radio and plan to install a DIY FRsky module so I was listening in here.
Thanks for the information....if I understood correctly the fix with the Schottky Diode is quite a "perfect solution" and is recommended for all radios when the DIY FRsky module is used, no matter if the ppm peaks are actually too high or not ( or even rather low) with the specific radio. So I do not need to check the ppm signal of my MC-16/20 with a scope ? (Unfortunately I don't have one...)

I am also using the Corona DIY module for some time.The Tx battery is a 3s lipo. Now I am wondering if I should do any fix for this module, too? ( maybe also solder in a Schottky Diode ?)
I am concerned since I saw the above....

Thanks for your help ,
Cheers, Romano

[RCModelReviews]

I'll be looking more closely at the Corona DIY system again this week and I['ll post an update regarding whether the mod would be required for them too.