BS2 Voltage Regulator Overheating

pSxMoD

Hi

I have the Basic Stamp HomeWork Board, and whenever i have it powered up, the built in voltage regulator gets really hot. It even gets hot when I don't have anything connected to the BS2's outputs or Vdd or Vin. Is this normal? I don't remember it doing that before.

sylvie369

What are you using to power it?

It is not, of course, normal. I've got one here and the only time it ever got hot was the one time I accidentally connected a direct short. If yours is getting hot with nothing attached except a 9V battery, you might want to closely inspect the board itself. Is there something conductive caught on it somewhere?

If you're using something other than a 9V battery, to power the board, please describe it.

pSxMoD

I'm only using a 9 Volt battery to power it. I don't see anything on the board that could be causing a short. I was wondering if operating this for longer than a few minutes at a time will cause the regulator to fail?

sylvie369

Well, it shouldn't. I've left mine on for a LOT longer than a few minutes with no heating or ill effects.

Has it always done this? Or did it used to work without heating up? I assume when you say "really hot" you mean "really hot", not "I can sorta tell that it's heated up a bit".

Duffer

Did you check the bottom of the circuit board to make sure nothing is there that might cause a short (or worse yet, is the board sitting on a conductive surface)? I once had a problem with a board that picked up the tiny shards of a broken magnet from my workbench and caused a short circuit.

Duffer

Carl Hayes

If truly there is nothing on the top or bottom of the board that could cause a short circuit, it is possible that an output circuit on the Stamp itself (the BS2 that's built in) could have a blown (shorted) output.· That could cause excessive current to flow through the regulator.· I suggest testing each of the 16 output pins with an LED and a series resistor of, say, 470 Ω.

Put in a program that will repeatedly cycle all the pins high, then low.· While it is running, connect the LED in turn to each output.· On each undamaged output, the light will flash.· If one is blown, the lamp will not flash, but will instead stay dark or stay lit.·

Here's a program that will work for this:

' {$STAMP BS2}
' {$PBASIC 2.5}
i VAR Byte
DO
····· FOR i= 0 TO 15
····· LOW i
····· NEXT
·· PAUSE 300
····· FOR i= 0 TO 15
····· HIGH i
····· NEXT
·· PAUSE 300
LOOP

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· -- Carl, nn5i@arrl.net