I have been working for a while on my wfly tx and by mistake put my tx lipo the other way around that means negative became positive and vice-versa 
now the problem is that my zener in the circuit inside has cracked and now is broken and i am very sad
what to do   please

Dear Prateek, Zenners are cheap! Check out an electronics spareparts shop and u'll get one. Else have a tv repair guy replace it for u. Good luck 

Quote from: martian2121 on November 08, 2010, 02:55:11 PM
Dear Prateek, Zenners are cheap! Check out an electronics spareparts shop and u'll get one. Else have a tv repair guy replace it for u. Good luck 

Is that Zenner ? then you need one with exact same voltage. Since the zenner is cracked, carefully try to de-solder it and see what volt it is meant for.

If it were for polarity protection, it could well be a general purpose IN4148 diode which has identical packaging.

Take help of your local TV repair guy if you are not familiar with Electronics DIY.

Quote from: ujjwaana on November 08, 2010, 03:18:08 PM

Quote from: martian2121 on November 08, 2010, 02:55:11 PM
Dear Prateek, Zenners are cheap! Check out an electronics spareparts shop and u'll get one. Else have a tv repair guy replace it for u. Good luck 

Is that Zenner ? then you need one with exact same voltage. Since the zenner is cracked, carefully try to de-solder it and see what volt it is meant for.

If it were for polarity protection, it could well be a general purpose IN4148 diode which has identical packaging.

Take help of your local TV repair guy if you are not familiar with Electronics DIY.

thanks for the idea martian !
@ujjwaana sir i am good at diy and no it is not an IN4148 as it does not look so also it is bigger in size

Hey can you post a pic?

Surely, its wattage rating is higher. That is why, it's higher in size. Can you trace the circuit position of zener diode with relevent buffer/transistor/Resistor. Please check the feeding IC voltage rating. Generally it may limit voltage to the Digital microntroller IC. If it's a COB, then another good set may be required to check the node voltages. If it's a standby safety device, you may bypass it.

Dont panic, If the zener is in series with resistance, it will be a voltage limiter, else, a safety device. Check the fuse in the circuit if available. Sometimes, narrow track can act as fuse. You need to connect them also.

If the rated power and voltage is not available, you can even regenerate that with a few  parts that will act similar and sometimes much better.

I am waiting for your reply.

photos attached for reference

more

yipeeeeeeeeeeeeeeeeeeeeee
wooooooooohoooooooooooooooooo

its working!
thank alot MR KALYAN PRODHAN
THANKS ALOT!

The are two parts of electronics in Tx excluding mechanical with POTs. The digital circuit consisting microcontroller and the real RF transmitter.

Actually the microcontrollers are kept running at 5 volt and the transmitters are also regulated to a lower voltage than battery supply. That is due to fix the frequency at a particular spectrum and does not shift with the voltage variation of battery.

It also sometimes servs another perpose. Limits the voltage and thus the power of the transmitter (and sometimes the final stage transistor too) to keep in a safe limit.

Therefore, better always check the allowable voltage of the transmitter part. You can increase the voltage by 0.5 volt by adding a 1N4007 in forward bias and boost your transmitter power a little bit. Again, replacing transistor with BLY90 or similar (Not for 2.4 GHz) insted of cheap 945 will also do the same trick.

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Better Not to open Tx before warranty and after warranty expire, open once and keep mark the node potentials in your drawings. Happy Troubleshooting.
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Pics added

Quote from: KALYANPRODHAN on November 09, 2010, 01:30:44 AM
You can increase the voltage by 0.5 volt by adding a 1N4007 in forward bias and boost your transmitter power a little bit.

Hi Kalyan,

Not sure what you mean by increasing the voltage by adding 1N4001 diodes. I think you wanted to mean decreasing the voltage by 0.7V for every diode added.

-Ismail