Possible triac problem

[The Master]

Hi. Ive got a slight problem with some boxes that Matt made for me ages ago. They use a PIC chip to control 8 triacs which turn on some lights. Im sorry but i havnt got any kind of circuit diagram or the origional code and Matt seems to have dissapeared from the internet.

The problem ive got is that one output is on all the time. This would usually mean its a triac that has broken. They usually stay off but ive been told they can stay on too. The weird thing is that the lights keep fading in and out in no particular pattern. Can a blown triac cause that? I wonder if i have a more serious problem.

I thing theres something wrong with the triac because the light turns on even when the PIC chip isnt powered

[Jerson]

Its difficult to diagnose without a circuit diagram. However, if you can post close up photos of the PCB both component and solder side, it might help someone here to possibly figure out the problem you're facing.

BTW: who is Matt?

[The Master]

Thats the problem, he revited all 8 triacs to the case so i cant see the underside of the PCB. Matt is ElectronicsUK BTW. Hes registered here somewhere.

Ive uploaded a PCB layout i made based on Matt's design. I still havnt got any schematic software yet. It might be hard to understand because the diagram shows components ontop of each other. In reality some components are under the board.

The circuit is basicly PC serial>PIC chip>opto isolator>triac>bulb

[mister_e]

Then get Eagle demo, get PrimoPDF and upload the schematic here.

Eagle
http://www.cadsoftusa.com/

PrimoPDF
http://www.primopdf.com/