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PIC pin 14 - weird voltage drop

PostPosted: Sat Mar 06, 2010 2:22 pm
by darkrot
Well, I've been fighting with my PIC for a while now and I still cannot get around with it. Especially, I'm worried about pin 14, where the measured voltage reaches about .5 V and then keeps going down. May this be caused by a faulty/wrong capacitor (I've used ceramic, maybe it should be electrolytic)?

Not to mention there has to be a short somewhere, because some pins with expected 0 V keep showing values around .6 V, some seem to be fine, there's 5V on pins 1 and 20, but it's this 14th pin that bothers me the most.

BTW, is there any way to check if the PIC is all right with just a mulitmeter?

PS. I've cleaned the pcb so there's no flux remaining on it, but this didn't work. ;)

Re: PIC pin 14 - weird voltage drop

PostPosted: Sat Mar 06, 2010 2:41 pm
by dmitri
darkrot wrote:BTW, is there any way to check if the PIC is all right with just a mulitmeter?

No.

Re: PIC pin 14 - weird voltage drop

PostPosted: Sat Mar 06, 2010 3:10 pm
by Firelord
darkrot wrote:PS. I've cleaned the pcb so there's no flux remaining on it, but this didn't work. ;)
I cannot think of any other cause for 0.6 V randomly generating on the board. Clean it from both sides, use isopropyl alcohol or acetone. You can also wash it with plain water with some soap (remove all ICs prior to this). Also, search the board for small tin fragments.