Hej!

My peggy 2 kit worked like a charm, everything was cool, could reprogram etc etc. It really is an awesome thing!

But.. something happened and I can't seem to figure out what.. Right now, nothing lights up when I turn it on, and the atmel turns into a heating element within a couple of seconds.

I'd like to read voltages, but I don't feel right to power it now, because it becomes so warm! Should i remove the atmel and then try to measure power?

Basically, what strategy should I use in order to find the source of this problem?

Thanks!

Jirka

If the microcontroller is heating up, STOP immediately and remove the power source.

Usually, this indicates that one of several serious things is wrong, and you need to diagnose it before trying to apply power again.

Some possibilities:

1. You have changed the power source, to something that is not appropriate. Reverse voltage or overvoltage or AC supplies will cause this sort of problem, and will likely damage other components on the board that are more fragile than the microcontroller.

-- If you are using batteries, have you put them in backwards?
-- If you are using a plug-in power supply, make sure that it supplies regulated 5 V DC, center positive.

If you are *sure* that the power supply is good, one strategy that you might consider is taking out the chip, and testing the voltages applied to the chip's socket, on the board, to be sure.


2. There is a short circuit, on the output pins of the microcontroller, or things connected to them.

-- Check the back side of the board for any stray bits of metal, or leads that may be touching. If you have a multimeter, check for connectivity between any two pins of the microcontroller, which might help to pinpoint the trouble. Some pins are *supposed* to be connected, so check what you see against the circuit diagram.

-- One possible cause of this sort of short circuit is if the leads of the components are not trimmed closely enough, and are touching somewhere.


3. Something else has changed, and not for the better!

-- Have you done anything else to the Peggy that might have been the cause of the problem-- like taking out any chips, or rewiring, or hitting it with a hammer? If so, that might be a good place to start looking for the cause of the issue.

Ahh.. checking and feeling incredibly stupid..

I switched power supplies apparently.. So I hooked it up to 12V one without ever noticing.

Allright.. damage control. What did I break.. pretty sure the atmel will be friend.. what else do you think is now busted..?

>So I hooked it up to 12V one without ever noticing.

Well, it's good that you found the problem. Allow me to suggest the Peggy 2 "repair kit":
http://evilmadscience.com/productsmenu/partsmenu/168

Most likely the microcontroller is actually OK-- those are surprisingly tough but the four other chips are likely in need of replacement, and it's good to replace the electrolytic caps as well when something like this happens.

Order it.. Thanks!