chips occasionally blowing?

[kenpo]

so here and there, ever so often, my 16f628 chips blow, and I have no idea why, tho I'm quite sure it's my own fault.

in the problamatic setup, I have 19 of them on small circuits, powering some ultrabright leds (x4) and sending a pulse to a counter chip to flash some other leds. some also send a pulse to a small motoer, but they are NOT driving the motor. it simply gets an ON pulse, and rotates once. (mac floppy eject... great little motors)
I'm feeding them a 5v power supply from a 200watt PC AT power supply, so it SHOULD be clean and perfect,...

what gives? one chip acctually fried and had burn marks all over (it was a micrchip sample, woudl that matter?)

it's artwork, so we're tlaking... maybe 2-4 blown chips everytime I do a week showing... it's a huge deal for selling the work, as I can't sell soemthing that pops and blows in 3 weeks....

I'm lost, any help from the more experienced is greatly desired..

thanks,
adam

[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....

[Acetronics2]

[QUOTE=kenpo]so here and there, ever so often, my 16f628 chips blow, and I have no idea why, tho I'm quite sure it's my own fault.

Hi, something hurts me ...

Tip 122 base connected directly to pic port ... I know there's a current limitation !!! but this is quite an unfair practice ...

Alain

[mister_e]

Alain... look post #7

@Ron
PTFS => Post The Fantastic Schematic?

[Acetronics2]

Alain... look post #7

@Ron
PTFS => Post The Fantastic Schematic?

Hi, Steve

My Maple Joe stock is at zero level, it's the only decent explanation i see ...my daughter (2 1/2 ) finished it !!!

2 votes in the same way ... that's to remember here.

amitiés

Alain