Frsky telemetry mod with 232 converter

All mods related to the frsky telemetry series of the firmware
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IanF9X
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Frsky telemetry mod with 232 converter

Post by IanF9X » Tue Dec 16, 2014 6:11 am

Mike

I've done the mods to the 9x ie cable connector for flashing, removal of 2 existing resistors and addition of 220ohm resistors from atmega pins. Flashed the 9x successfully.

Built the max232 converter, cut traces on back board of 9x as instructed, and added resistor and link to djt module.

So when I power radio I here the djt beep and appears to be working ok but no screen whatsoever. So I simply unsoldered the 5v supply to the max232 and hey presto I have screen working. Any voltage checks I can make on the 232 circuit?

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jhsa
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Re: Frsky telemetry mod with 232 converter

Post by jhsa » Tue Dec 16, 2014 6:26 am

You must be shorting or loading the 5V power rail too much. A picture of the assembly could probably help.. ;)

João
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IanF9X
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Re: Frsky telemetry mod with 232 converter

Post by IanF9X » Wed Dec 17, 2014 12:08 am

Thanks Joao for that I figured it must be a short or something perhaps in the 232 circuit, will make more checks. Is it definately a 470 ohm resistor on the 232 circuit or is it 47 ohm

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jhsa
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Re: Frsky telemetry mod with 232 converter

Post by jhsa » Wed Dec 17, 2014 12:55 pm

470 Ohms

João
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IanF9X
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Re: Frsky telemetry mod with 232 converter

Post by IanF9X » Sat Jan 03, 2015 7:29 am

Just a quick update Joao. Checked the vero board connections on the 232 board and sure enough found a sliver of track that was bridging 2 pins (must have happened when using dremel to break track) so cleared track and hey presto all good. Thanks for your help.


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jhsa
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Re: Frsky telemetry mod with 232 converter

Post by jhsa » Sat Jan 03, 2015 8:51 am

Great that you fixed it. ;)

After cutting the tracks on the strip board I always clean it with some steel wool to remove any little pieces o copper.

João
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