PLX SM-AFR Serial upgrade

[thunder550]

Ok, that explains the voltage chip on the RS232 connector, but not why it's necessary to open up the PLX box and solder new wires in there.

[thunder550]

Ok here's what I found on the stereo minijack plug that carries the PLX serial data, for anyone that cares.

Tip carries +3.3v
Middle carries the serial data
Base is the ground.

**edit*** - this is incorrect


So what I'm thinking is that I can put a regular headphone jack Y splitter on there, use one to transmit to the gauge, and use the other to transmit to EFILive.

The EFILive one would have to go through the voltage regulator chip as listed above, from my understanding.

[vxleather]

okay SO.... If i had a little case.. which i do... and grabed my multi meter.. i could work out the 3 out pins of the RS232 and simply remove the actual plug part leaving the board assembly.. solder the three wires needed to each side of the board and connect the right plug for the v2 to the end.. this allowing a quick connect plug system... hhhhmmmmm... i like this i do... so no need to cut up the plx box.. etc etc..

[thunder550]

Sounds like it should work.

Here's what I'm planning on doing. I'm using the Null modem adapter because I already have it...bought it to hook up my old LC-1 and it's easier just to reuse it.

I ordered the MAX3232 from ebay yesterday...hoping to have it by the end of the week so I can get this all hooked up and try it out.

[JezzaB]

vxleather tried this the other day and it didnt work. He had to solder into the board in the end.

[vxleather]

Yep the phone jack thing don't work.... As the tip of the pin which we think is the power outlet is actually the signal outlet.. and therefore there is no power to power the 3v board..

After i tried many different things... wore out my multi meter... I went back and looked at the first photo's in this thread. If you look at where the wires are soldered to the board, The signal actullay is taken form the top of the pin in the mini jack port..

[Shupe]

Yep the phone jack thing don't work.... As the tip of the pin which we think is the power outlet is actually the signal outlet.. and therefore there is no power to power the 3v board..

After i tried many different things... wore out my multi meter... I went back and looked at the first photo's in this thread. If you look at where the wires are soldered to the board, The signal actullay is taken form the top of the pin in the mini jack port..

Is the 3.54v on the circuit board better (more stable, cleaner) than the 3.3 available on the analog plug top left pin? My thought is that if this power was acceptable to power with the modification of a mini jack plug would keep from making modifications to the module itself.

[thunder550]

Hmmm...I got my MAX3232 in the mail yesterday, planning on working on it tomorrow. Will post back with my findings. Thanks for the information above guys, I'll take that into consideration when I'm working on it.

[thunder550]

OK just a quick look at the PCB says that the tip of the minijack connector is Tx, base is ground. Doesn't look like the middle contact has anything connected. Might try to connect power to the middle contact.

[vxleather]

Is the 3.54v on the circuit board better (more stable, cleaner) than the 3.3 available on the analog plug top left pin? My thought is that if this power was acceptable to power with the modification of a mini jack plug would keep from making modifications to the module itself.

There is no out put voltage to power the convertor board on the mini jack!!!