I'm bench testing my P1900 using a 12v power supply. After setting the jumpers for the primary, secondary, and 5v output I did the following...
1. Connected the ground wire from teh P1900 to the - terminal on the bench power supply
2. Connected a lead with a splitter to the + terminal of the bench power supply
3. Connected one end of the split to the red power wire from the P1900
4. connected the other end to a switch, then to the yellow ignition wire of the P1900.
I hit the power button on the bench power and the on button of the inline switch and got the fan of the P1900 to fire up then slow down. The LED blinked at a slow interval.
I then connected my multi-meter to each of the ouwer output lines and verified that they were putting out the correct voltage. 19v for the Primary, 12v for the secondary, and 5v for the 5v regulator. Perfect...
I then shut off the switch between the ignition line and the bench supply to simulate the car being shut down and the system stayed on for a few moments, then finally shut down.
The multi-meter was connected to the primary output the entire time. When the fan for the P1900 shut down, the voltage on the primary output dropped...but ot down to 0. It went down to 12v instead.
Shouldn't the P1900 power output go down to zero instead of 12v?
Great! Thanks for the info. I was just making sure that there was nothing wrong and it was working properly.