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[craptain]

I'm only asking because I think I might have fried this little toy keyboard I picked up. I have successfully bent and installed components before. This time, I found a bend near the black blob/timer circuit that would slow down everything when I touched both contact points with my screwdrivers only connected by my body.

I was thinking of a putting a pot right there but wanted to see what would happen if I connected without resistance by putting alligator clips on both the ends of my two screwdrivers. The keyboard froze on a single droned tone, which is something I've seen happen before, and I took the batteries out and turned it off to try and reset it.

But now when I turn it on, it makes a little pop noise and the leds light up for a second, but then it doesn't respond at all. I haven't soldered any new connection or cut any lines. Does that mean that this keyboard is "fried"?

[Dylan]

Sounds like you might have. I'll tell you what I tell everyone though, take the batteries out, discharge the power caps (take a flathead screwdriver and touch the cap leads together near the power source), and let it sit for a week or two.

[Circuitbenders]

Isn't the point of discharging the caps so you don't have to leave it for a week? Surely leaving is for a week just lets the caps discharge naturally over time.

[Dylan]

I've had circuits need to sit after discharging.

[Bogus Noise]

Yeah, I believed that bridging the legs was to discharge the capacitors instantly too. Although I've also had caps discharging not work but leaving them to sit for a while sorts it out.


Sounds like the keyboard could be fried though. Some things are a bit more sensitive and over/underclocking them is a bit much for their fragile little circuits. But see what happens after leaving it for a couple of weeks, things can mysteriously work again... even *after* cap discharging 

I do hate frying things though, it's sad when you get that device just repeatedly trying to kick into life but never quite making it 

[dislocations]

I think the leaving for a week is a good call........it's worked for me after discharging. Incidently. this happened to me a long time ago and although it never fully recovered it sounded great!

[craptain]

Thanks for all the input. I think this keyboard is totally fried. It's no big deal, but I still don't really know what it means that it's "fried". All I know is that it doesn't work at all anymore.

Something somewhere is just burned out, right? I'm not trying to salvage it, I'm just curious. For it to be totally fried does it have to be something like the ic got messed up on the inside? Or whatever is under the black blob burned up from the inside?

[Circuitbenders]

I guess 'frying a chip' could mean any number of things. Sometimes the internal structure of an IC might be burnt into one state by too much current, or the internal power rails might have just melted, or something might have shorted out internally. If its something thats programmable like an EPROM or microcontroller it might have become scrambled or corrupted.

Alternatively there might be an external problem thats holding an input or output of a chip in a certain state which is making it stall or shut down.

In my experience black blob circuits are unlikely to have anything in the way of overpower or short protection protection, so i'd imagine its entirely possible that something will just melt internally under those circumstances.

Don't worry though, it gets more exciting when a chip just goes pop and explodes off the board