TreadBot

[skimask]

my last question for everyone is: For PICs that have multiple Vss and Vdd's, do they all need to be connected (they are on this board), or are they connected internally?

All Vss's must be connected together outside of the chip, same with Vdd.

And nice job on the PCB...really. The only things I was going to mention...mister_e already covered them...

As far as overheating, with the PIC out of the socket and power disconnected, if you put a meter between any Vss and Vdd, what do you get for a resistance reading? How about a Vf reading (normally seen as a continuity test on a meter when really it measures a diode's forward voltage)... Now try it with the PIC in the socket and power still disconnected?
Then hook up the meter to Vdd & Vss, turn it on volts, put the PIC in the socket, and plug in power just long enough to read the meter. Did the meter come up to system voltage? In other words...dead short somewhere on the board?

[dragons_fire]

As far as overheating, with the PIC out of the socket and power disconnected, if you put a meter between any Vss and Vdd, what do you get for a resistance reading? How about a Vf reading (normally seen as a continuity test on a meter when really it measures a diode's forward voltage)... Now try it with the PIC in the socket and power still disconnected?
Then hook up the meter to Vdd & Vss, turn it on volts, put the PIC in the socket, and plug in power just long enough to read the meter. Did the meter come up to system voltage? In other words...dead short somewhere on the board?

1.036kohm across vdd and vss "with" and "without" the chip. i tried another regulator that isnt mounted to anything, and it comes back with the same reading.

5V without chip, 4.48V with chip

when i put my meter on the doide symbol (i have never used it before and dont know what it is), i get .324V without any power applied to the board (im assuming there isnt supposed to be)

[skimask]

1.036kohm across vdd and vss "with" and "without" the chip. i tried another regulator that isnt mounted to anything, and it comes back with the same reading.

1-ish Kohm... hmmmm...no dead shorts. Something is turned on by the PIC.

5V without chip, 4.48V with chip

Something's loading it down! Try disconnecting the motors? Try disconnecting and unsoldering stuff until you find the 'leak'. Maybe change your program a bit to make absolutely sure nothing is being driven for X seconds before something starts to happen.?.?

when i put my meter on the doide symbol (i have never used it before and dont know what it is), i get .324V without any power applied to the board (im assuming there isnt supposed to be)

Try this with the 'diode' symbol on the meter. Hook the meter up to a plain ol' diode, 1N4148, whatever you've got handy. Whatever the meter reads (within range of course) is what the forward voltage drop of the diode is and if the meter leads are connected correctly. The datasheets on the diode will tell you what the nominal values are. You can also use this function to correctly identify leads on a transistor.

[dragons_fire]

to be honest, when i said everything was soldered to the board, i really meant there a couple things soldered to the board... right now it has the regulator, the PIC, OSC, power switch, headers and i have a diode, resistor and cap on the MCLR pin.. they are connected exactly the way it says too in the march 2007 nuts and volts... mclr goes to the programmer, then there is a diode off of that, with a 4.7kohm resistor to dvv, and a 1uF cap to ground.

it gets so hot so quick, that i havent programmed anything into the pic yet, and because its a plcc, i cant really use my breadboard to try it...

im heading to work though, so if i get a chance, i may look at it some more to see if i can find any shorts on any pins, and make sure i have the mclr stuff on right..

[skimask]

I'll put money on the MCLR diode put in backwards.
Any takers for odds?

[mister_e]

i'll bet on at least one I/O short to GND (Vss) or short to another I/O. Try to set all unused I/O to input. But before, remove the PIC, measure impedance between ALL i/o and Vss, then Vdd.

Something suck juice here...

OR, a VSS is connected to VDD and so on... kind of routing mistake

If the MCLR pin was just put backward... the PIC would just act oddly... not suck as this juice.

How about the current measure?

[Darrel Taylor]

I'll put money on the MCLR diode put in backwards.
Any takers for odds?

I'll take that bet.

It's got to be the Plethora of shorts that mister_e pointed out in the picture.
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[skimask]

I'll take that bet.

It's got to be the Plethora of shorts that mister_e pointed out in the picture.
<br>

But the poster did say that the regulator/etc didn't get hot until he put the PIC in the socket. Doesn't really make sense to me either. Maybe the stress across a couple of pins on that socket are shorting out only when the chip is in.