troubleshooting method for micro-controller board ?
I'm reading this thread with some interest, but I'm more puzzled as it
goes on, there should be something we are (and the OP is) missing.
On 16 Nov, 19:11, "robb" wrote:
"clifto" wrote in message
....
....
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
hmm 78xx don't smoke easily, maybe if you apply a too high input
voltage ( 30V I believe) or if it goes into self-oscillation if an
output capacitor is omitted. A 100 ohm resistor, assuming we are
talking about a 1/4 W one or bigger, shouldn't smoke easily with only
5V even on a short to ground, it should become quite hot but not smoke
instantly, if it smoked I believe the input voltage was higher.
Power supply problems shouldn't be that difficult to troubleshoot,
even if once I had almost the same problem with a simple three tubes
amplifier, but that was another story :-)
Regards
Francesco
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