Picaxe 28x1 got burned..anything to do?

shaked87 · February 18, 2009, 8:54am

it’s a sad story..

I was working on my robot trying to make a servo turn the directions i wanted

After I got the positions I wanted from the servo I connected it to the front wheels axles and plugged it in again, just like before

Only this time something got burned, smelled the motors, wasn’t it, smelled the board, and let’s just say it smelled funny!

Tried to connect it to the computer- nothing, the sensor led is not on as well (it should be on).

________________________

So it’s obvious something is not working in the board, the question is what?

The servo motors did get a 7.2 volt through v2 and let’s assume somehow It got to v1 (although it worked ok before with 7.2 volt in v2):

Anyone have any idea what is the first thing that can get burnt if high voltage will get to the board?

I’m pretty desperate… any help would be much appreciated.

Thanks, Shaked.

motherhugger · February 18, 2009, 10:02am

what power supply did you
what power supply did you use to supply picaxe?7.2v? IMO the first thing that get burnt is the capacitor or the ICs

shaked87 · February 18, 2009, 10:27am

the picaxe was supplied with

the picaxe was supplied with the ~5volt that it came with.

i think that somehow the 7.2v from v2 got there , cant think of any other reason for it to get smoked.

what does ICs stands for??

electrictape22 · February 18, 2009, 10:50am

well…
Did you use a resistor with the servos? And ICs is plural for IC. IC means integrated circuit.

rik · February 18, 2009, 10:54am

Chip

IC = Integrated Circuit is the chip (in this case the micro controller).

Maybe you need to replace the voltage regulator on the picaxe board. That could be the burnt item. I cannot tell without measuring a few things. Do you have a multi meter?

shaked87 · February 18, 2009, 10:54am

i used a 330 ohm resistor

i used a 330 ohm resistor with the servos, but i dont think it has anything to do with it…

i cant seem to find a detailed datasheet of the 28x1 picaxe (axe020)

i think that when i see it i might be able to understand the would go wrong first

anyone have a datasheet the contains all the components of the board? (including capsitors for example)

thanks

shaked87 · February 18, 2009, 11:01am

i didnt know the board had

i didnt know the board had voltage regulator can you tell me where it is?

i thought about replacing the capacitor above the leather E near the right bottom corner.

assuming ill get a multi meter what should i check first?

jklug80 · February 18, 2009, 11:06am

When you hooked up V2 did
When you hooked up V2 did you remove the jumper? If not you may have sent both power supplies to the IC.

rik · February 18, 2009, 11:16am

You’re right

There is none. I shouldhave checked the image you linked myself.

But this could still mean you damaged your (off board) power supply. Not likely though. Just make sure to check.

The capacitor you talk about is rated at 25V (on my picaxe 28x1 board anyway: I really should have checked this!). The cap is probably still OK. Unless you reversed polarity on V2 as well.

With a meter, you could remove the PIC micro controller first and then measure if all the V1 pads are still giving you the right voltage when powered up.

And you might want to measure resistance between V1 and GND (when not powered). It should be high. Very high. Your multimeter should read “-1” or “E” or something.

shaked87 · February 18, 2009, 11:24am

yeah i removed it.i know it

yeah i removed it.

i know it did it good because everything worked

i think somehow a wire moved or something like that

i know it sounds wierd but i see no other way to explain it

shaked87 · February 18, 2009, 11:59am

thanks :)now ill know what

thanks

now ill know what to check when ill get a multimeter.

will update after checking all you have mentioned

once again thanks.

shaked87 · February 18, 2009, 5:21pm

updating after a multimeter check

all v1 points seems to be fine exept the 2 in the left bottom corner (with the letter G between them)

these 2 spots has a lower voltage reading (~ 3.5 instead of ~4.5)

if it matters i dont have the 10k resistor next to it shown here:

anything else i can do?

rik · February 19, 2009, 3:46pm

I’m out of ideas

Maybe someone else has more options.

The pads around G are probably GND pads, not V1. This still does not explain the 3.5 V. Or the absence of the 10k resistor.

Here’s a comforting thought: replacement PIC chips (with picaxe bootsrap) are dirt cheap. Ordering one and having it delivered on the other hand…

shaked87 · February 19, 2009, 7:25pm

OK, i fixed it!im really

OK, i fixed it!

im really happy to tell you that i fixed it!

i don’t know how i missed it, but really near the same spots i said i the reading wasn’t v1 (with the G between them),

i saw some sort of metal, coper maybe underneath the black material that covers the board( the semi conductor i believe)

it had a hole in the some kind of a strip ( small but big enough for me to see it)

i measuerd it with a multi meter, one side had v1, the other showed nothing

so i soldered the 2 spots togheter and thats it!

everything works.

just wanted to say thanks to anyone who posted here, trying to help really means alot.

this is a great community and i really appreciate it.

thanks, shaked.

ndupont · February 20, 2009, 5:02am

this remind me the day my

this remind me the day my board smelled funny…

I had the very bad ‘parallax-guy’ feeling that I had to use the jumper to cross the 2 other pins…

the smoke came from the wire below the batteries holder