Carrier Window AC 19,600 BTU with Remote / Model is APX195BA

Use 25volts AC output transformer

70 Volts is too low. IT should be the same as the house voltage. Check the outlets and breakers.

High voltage goes to board then to transformer. 24v comes out transformer into board. Check high voltage going to transformer if have votage but no low voltage out other side 24v then transformer is bad.

check high voltage going to board and transformer then check low voltage from transformer to board. If you have voltage on these board is bad. Correct voltage that is.high 110v-120v low 24v-28v

If the DC is 15v then the AC is around 12v.

I have the same problem, with the same transformer. Did you ever find the specs?

I was thinking of buying the Frigidaire board, connecting to line voltage and measure output voltage.

Sounds like it could be your transformer. See if you can locate it. It should be in the air handler indoors. Check the voltage going to the transformer and check the output of the transformer. You should have around 24 vac on the output of the transformer. If you don't have voltage on the output make sure you have it on the input (120vac). If you don't have it on the input you need to find out why. If you have it on the input but don't have an output then your transformer is likely gone bad. Let me know what you find.

The buzzing sound your hearing is a transformer that is producing 24v ac current to the main control Board, this is what controls the unit. you can check for 24v to the main board by removing the front panel access door and finding the safty shut off switch that the door touches, and depress it or tape it so you can test for voltage.. if you have 24v ac from the transformer next test at the board, if you have voltage there you may have board issues??? check the fuse on the board, make shure all connections are good... if you do not have 24v to the board your transformer is bad, have a hvac technician service this, don't attenmpt to do this yourself if you don't have experince, you could destroy your cont. board.....
hope this helps