Give Me Circuit

It sounds like the scale power supply had burned up?

You are going to have to apply a voltage to the strain gauges and then monitor the current as the strain is applied. Unless you know what that voltage is and what the calibration of the strain guages are you are going to have to re-calibrate by hand with known weights. Once you have the output of the strain gauges through a high impedence op amp you can connect to your A/D converter and thence to the RS232.

Without a schematic of the system we aren't going to be able to help much more. On the other hand if the power supply is what has fried you might just be able to go to a hobby shop and buy a wall wart of the right voltage and wire that in. Or buy a variable voltage wall wart (Radio Shack has these) and just start at the lowest voltage and work your way up until you get a reading or more smoke....

Buy a little PLC Versamax with analog inputs and connect the strain gauges there; then program it writing the scale data to the serial port and send it to your computer, The Versamax literature has extensive and pretty straight forward instructions for doing so. You'll need known weights to program the "SCALE" function.

I used to build a lot of PCB, but I became lazy and started using off the shelf devices.

Yahlasit