somthing wrong

[ignotus]

You say the board had been working and that it suddenly stopped working - if that's the case I'd go over it with a magnifying glass and look for hairline cracks along tracks or on solder joints - sometimes they're so small they're almost invisible. And instead of measuring voltages all over the place, test for continuity.

[marcjwebbmusic]

if my atmega644 is blown would be a possible cause?

regards

marc

[ignotus]

I'd say a blown atmega would be a consequence, not a cause. If it's blown, it's because something was placed the wrong way around, there was a short, reverse polarity applied, or something else... that's what you'd have to look for. Does your computer detect it when you connect it via usb? Do any components get hot when you plug it in?
I once accidentally reversed the voltage going in and the pic heated up so much you couldn't touch it (the atmega seemed unaffected). Apparently not a single component was damaged and 6 years later it's still working, nothing needed replacing. You may have been unlucky (and I very lucky) but I'm inclined to think that there's something you've overlooked. Post or link to close-up pics of the top and bottom of your board, maybe someone can spot something.

[marcjwebbmusic]

thats a great suggestion, thank you,

the only thing i can think of is the fat that i was woking on the enclosure, drilling holes, cutting lcd hole yesterday and it is possible as there was a fair bit of metal dust and stuff like that from the enclosure.

similarly, i drilled out the holes in each corner of the pcb, but from what i can see has not actually gone anywhere close enough to do any damage, unless the pressure of me holding it down did.

ill post a pic of both back and front shortly, like you say, maybe someone can spot something

thanks again

marc

[marcjwebbmusic]

here is the bottom

http://www.flickr.com/photos/110501144@N07/11194718143/

here is the top

http://www.flickr.com/photos/110501144@ ... otostream/

[marcjwebbmusic]

ok, so from your suggestion, i tried the pc route.

the pc recognised it, installed it, and said ready to use, so i disconnected it, connected the lcd, re-connected it, and up came the screen, input pins reacting.

then turned off again, GRRR

so i know that both the pic and the atmega644 are ok, otherwise it wouldnt have done anything at all???

anything you can suggest from this point?

regards

marc

[ignotus]

If it turned on and appeared to work for a while, it's probable that there's a bad connection somewhere. Plug it in, pick up the pcb and gently bend it one way and another. If it turns on/ off you most likely have a tiny crack or bridge somewhere. Be careful, because you don't want to make a crack somewhere else. This happened to me and it took ages to find the fault.

[marcjwebbmusic]

hi all, hope everyone is good and doing well,

i have recently had some strange behavior from my digital board in the sense that when i plug it into a computer, the computer recognizes it and shows to be connected,
i get nothing on the LCD, and no blinking from the midi activity led.
what is really bizarre is that i had no problem, then 2 days ago it tarted doing this. but the last night it did turn on and show the messages, then slowly turned off then nothing off again and so the situation is the same now.
i have taken some pictures of the board back and front, and was wondering if a fresh pair of eyes might be able to spot something.

http://www.flickr.com/photos/110501144@N07/11194718143/ (board bottom)
http://www.flickr.com/photos/110501144@ ... otostream/ (board top)

if anyone can help then please feel free to message.

Many Thanks

Marc

[dmitri]

I can advise you two options:

1. Meticulously go over the board with a meter checking for shorts/breaks.
2. Start from scratch and make another board.

With the first option you still may end up having to do the second option if there are loose/bad contacts/soldering points or faulty components which you may not be able to detect with a meter. A few times I had problems with boards I built it was easier and faster for me to build a new board rather than wasting my time trying to find a fault.

[marcjwebbmusic]

ok kl, i think ill have one last go at making the board either that or just buy one from you lol.

regards

marc