chips occasionally blowing?

[Jerson]

Post your schematic here. It will help with the guessing.

Jerson

[Ron Marcus]

Are you driving the LEDs directly?

[kenpo]

the LED's aren't drive directly (I thought the pic could drive an ultrabight anyways though...)
though the other ultrabright leds ARE driven directly by the counter chip, on the second baord (the second board is just the counter chip + leds, pos/neg, and signal line from pic)

here's the scematic (edit: schmeatic of the main board, that is, it has mounts for servos and tip 120's, but I'm only using ONE servo mount to control the mac floppy motor thus far)

[Melanie]

OK and the other holes wire into a Tesla Coil?

Let's not make life difficult... post a proper schematic not a PCB layout which is bad enough with proper component idents, but without is just impossible.

[kenpo]

unfortunetly I don't have a proper schematic, I use windows paint to make my layouts....

[mister_e]

Let's do a guess from what i can understand of it. Are you really sending your PIC i/o directly to the base of your TIP122 without any resistor in serie with the base? if so... your problem is there.

Also, as those transistor have already resistor between base and emitter.. you don't really need those you place.

If you don't want to do PCB modification, you change your TIP122 to a mosfet, some, see all, Logic type can be driven without resistor in serie with the Gate.

[kenpo]

here's the thing, the circuit has alot of ports, like for the tip122s, but they're not being used as of yet, only ONE of the 19 boards I used a tip122, and that one hasn't blown, it's perfectly fine... which is odd,( I'll obvisoly add the resister as you suggested though for the next revision, I have no qulams about redesigning and reprinting the board. I need to make more anyways).

what's being driven from the pic is the mac floppy motor, and the counter chip.
so the circuit isn't really as complicated as it has space for, there's really only like 4 things on it usually.

I'm wondering if I need to some how buffer the incoming voltage??? is the 5v clean enough? should there be a resitor somewhere for the pic voltage incoming or outgoing... I mean, really, all I cna think of (other than the tip problem, which hasn't been the source yet) is that the mac floppy needs a diode on the signal pin, perhaps theres feedback being thrown back to the pic? I send a HIGH pulse for 800 (pause) then the motoer does a rotation once around.

and running the 16f628a on internal clock, is this bad? I'm wondering if I've hooked in one of the traces to the pic wrong or something....

also, a few osc crystals blew, but I've heard that can happen alot...? so i started using the 628 to avoid external clocks