"clifto" wrote in message
...
robb wrote:
I connected the 5v (through 450 Ohm) to the PCB 5v and 0v
lines.
i measured ~60 mA curent nothing warmed ...

That's pretty good. If you then shorted the PCB 5V and 0V
lines, you would
have 450 ohms across 5V and should read 11.1 ma.

i idecremented the
resistance by 100 for each iteration of testing the measured
currernt increased slightly until i made it to (100 Ohms) and
then the current spiked to ~+ 1.5A and the 7805 fried ?

To get 1.5A through 100 ohms you need to apply at least 150V to
it.


thanks for reply clifto,

i will have to believe you on the numbers

and although the numbers may seem incorrect from a electronic
formulaic analysis i can only report what i see on the equipment
i use and with the setup i use.

The DMM amp reading numbers were fluctuating wildly on my last
test and 1.57 ???was something i thought flashed by as highest #
maybe it was .57 but i do know that whatever the number the 100
ohm resistor had a stream of smoke going up and the 7805 appeared
to have a puff of smoke released before i could dis-connect now
i am hopping somebody can help me decipher what went wrong with
my testing

even operator errors would be useful as long as it helps nme
omove toward a repair/
robb