MAX232 output always negative

[rsmith8917]

Hello,

I am trying to connect a MAX232 IC to a dspic33F to perform rs232 communication with a PC. I've wired up my MAX232 and when I give it a 5v signal, I get -8.5v out, but when I give it 0v I am getting -5v out. I've checked the wiring again and again, but I can't seem to find the problem. I have it connected just like in this schematic

Any help would be greatly appreciated. Thanks.

 

[alexan_e]

Why have you used different channels for input and output (R1 and T2)?

 

[rsmith8917]

Thanks for the reply. That was a mistake in the diagram, but I actually have everything connected to channel 2.

 

[alexan_e]

Your -5v seems low, for me it is about -9v.

I just tries with a max232 and I got -9.5 with 5v input and +9.5 with 0v input so maybe something is wrong in your circuit.

What is the voltage at pins 2 and 6 referred to the ground?

 

[rsmith8917]

pin 2: +8.4v
pin 6: -8.1v

Thanks again for the help!

- - - Updated - - -

Just as a note, I've tried using channel 1 as well and I'm still getting the same result:

5v in -> -8.5v out
0v in -> -5v out

 

[alexan_e]

Are you testing with the PC side plug unconnected, maybe if you have it connected it is effecting the result.

Your pin1 and 6 voltages seem good enough