Yes, why not. The existing VR seems to have gone rogue anyways. I'd do this if I was in your shoes:

1. Desolder the assumed rogue VR, mark the Vout and GND pads.
2. solder two wires on the Vout and GND pads and connect them to 1.2 * 4 = 4.8 v rechargeable batteries (or a 5v mobile phone charger - without forgetting polarity) and check the ATMega if it's still sane.
3. Wire up the new one on a bread board, and check the supply one before actually trying to solder it on the motherboard.

Got it, thanks you Girish. Will try this tonight and report back.

I am a bit dissapointed that im unable to help you out.The thread helped me a lot.
I have a working radio.
All i can do is to check the things like voltage, resistance, etc. between points via multimeter and revert back if you insist.

Just let me know.

Thank you Abhay.

My new findings almost certainly confirm that the atmega is toasted. Removed the vr and connected 4.9 volts where the output terminal were soldered. Identified GND and VCC on the chip but found out the VCC pins are kept unused but AVCC is used. Measured voltage on GND and AVCC and it was 4.23, this means the voltage at the output of the VR was being fed to the chip. This means the chip has seen 10.7 volts on these pins. O the horror it must have been through

You are too girlish to feel the pain of a lonely chip

  so this one is going in the drawer for now.. may be i'll get a SKY9x board for it when it comes back in stock. Will get my new 9x this weekend, thanks to Saurabh for a nice deal  Hopefully the new one will stay with me a little longer  

Time to hunt for a second hand 9x o salvage the mega or get hold of the ersky board.

Hi guys,after a long gap I thought to do some RC activity..I tried to modify my Turnigy 9x for a Life bttery and finally...
yes its burnt 

do not worry... it can be repaired.... hopefully you connected wrong polarity !!!

google it on net you will find solutions.

Krish there are some fuse wires inside the tx.. just open the back cover and check which one is burnt.. and replace that...
Don't worry..

Sent from my Canvas using tapatalk 2

Hi frnds,finally my tx got life by Girish  ..Thanks a lot for ur help Girish  ..

Always a pleasure sire.

Sanjay sir is going to kill me now, His Rx is like 5% away from completion for a long time....

Bang....you're dead

I joined this elite club of TX burner few days ago.

Here is exact status of my TX:

When TX is switched on, it boots up properly but does not bind to RX.

The light on FrSKY module does not glow.

I checked the voltage at the module input and it is around 4V.

As per specs of FrSky DIY module it needs input of 6-13 V.

Can you please guide me which VR (or any other component) is faulty?

Tried to search it by multi meter but was not able to find faulty VR as both the VRs near to capacitor gives about 4V.

Capacitor is showing 5v though.

Let me know if you need any other input.

Please help.

Try some basic chexks first. See if your frsky module is alive...hook it up.to a cellphone charger in corect polarity and confirm if the led lights up. Mosy likely its one of the vrs. What did u do ? Ulta battery?

@atul : may i know your binding procedure?? because i had frsky module and in the beginning i found really difficult to bind it , later i followed some manual binding procedure then it got binded 

Thank you Girish

yes cell ph charger is good idea ..... i will try that.

I too think its one of the VRs .... but not sure... which one....

Nithinraj, it was already bind with rx but after polarity issue module light is very dim on 3s & completely off with 2S

If any one have good idea to locate faulty VR then please let me know.....

Thank you,
Atul

First use "use and throw type" AA battery having internal impedence and check the current and voltage.
The results tell a lot. Then power up block by block. and check. Please also check the Rx with a separate Rx first to eliminate Rx fault possibility.

Thank you Kalyan.

I will post results of these test ASAP.

This RX used to work fine with same TX and module light does not glow so I suspect its issue on Tx side.

But I got your point that before jumping to conclusion we should check all possibilities and be 100% sure.

Thank you.

ok, i tried to power the FrSky module with 4 AA cell and nothing happen.

After opening the module cover i noticed that one IC is burned other one is getting very hot.

Here is pic of module that shows burned IC.

I cant read the complete # on IC  as its partly burned.

Here is what i can read.

164331
****BM
****CY

This is the first IC on board that is connected to power input wires.

My guess is this also VR.

Please let me know if i can replace this burned IC/VR? where can i get this? what is complete # of IC?


Also any details you may have...

Thank you,
Atul

Ok, Quick google search tells me ... It's a Texas Instruments TPS 54331 3.3 volt 3 Amp regulator

Next question is : Should i just replace VR of module and try again or should replace all of following?

1x VR (Part # LM78L05ACZNS-ND)
1x VR (Part # 296-11118-1-ND)
1x VR (Part # NJM78M05FA-ND)
1x VR (part # TPS54331EVM-232 3-A)
1x Cap (Part # 478-1682-1-ND)

can any one tell me what should be reading of out put V for all of above?

http://www.aliexpress.com/wholesale?SearchText=54331&catId=0&initiative_id=SB_20131122200922

Getting one piece might be difficult and expensive from Ali. I can find around locally in Chandni Chowk and let you in a day or two.

Spoke to some guys around. They dont have the TI 54331. They only have the LT117 which I don't think is a drop in replacement nor has adequate throughput (650ma vs 3A) so the best bet at the moment is Ali