I bought a PGM03A a couple weeks ago. It was working great, everything I’d hoped for, until tonight… In the middle of working on my project, my upload failed. The lights were off, so I went to power cycle it, and I found it was hot, in a “this chip will never work again” kind of way.
Can I exchange it for a cooler-running one?
Burning up is definitely not normal behavior for our programmer! Can you describe exactly what was connected to it at the time and how you were using it? Is it possible that anything could have temporarily caused a short - like loose wires with exposed conductors, or metallic objects that could contact the board?
A picture of your setup would also be helpful.
A picture won’t help much, since I unplugged it and switched back to my old Butterfly loader and FTDI TTL-232 cable. I could hook it up the way it was, but it’s easier to just describe it:
My target is a couple custom boards (goldphoenixpcb.biz rocks!). The one I’m working on is mounted on a sheet of acrylic, and laying on my desk. The programmer connects through a ribbon cable to the ICSP headers, plus a couple F-F jumpers (Made from the DIY jumpers/housings you sell… Thank you so much, I’ve been looking for something like this for a long time!) from the programmer to pin headers on my target board for TTL-232. The TTL-232 just uses the ribbon cable for ground. I also have jumpers coming off VBUS/GND/A/B, but those weren’t in use at the time. The only other wiring I have outside the chassis is a cable bundle going into a KK connector, and a display on an FPC. There’s ample opportunity to short to ground (anywhere on the chassis), but I wouldn’t expect that to fry anything except possibly the VBUS trace. Everything else is pretty tidy, since I’m off the breadboards and onto the custom PCBs at this point. I can’t 100% rule out a short, but I think it’s unlikely, especially since I was just hacking software at the time when it went.
The chip itself is definitely fried - Just plugging it into USB makes it go hot. I probed the potentials between all the pins, on the off chance that my chassis ground was floating up above USB ground, but it’s not… the grounds are equal, and the signals are all 0-5v.
The one goofball thing I have is some LEDs on MOSI. They flicker and sink a fair bit of current when the master wants to pull the line up. Perhaps I’m a bit spoiled with the current an AVR can source, and the overcurrent protection they have. Could I have fried the PIC this way?
Thanks for the detailed description. The I/O lines should definitely be able to handle driving a few mA of LEDs. On the other hand, shorting random lines to ground could easily damage much more than just the VBUS trace!
Other than advising you to be extra careful in the future, there is not any more technical support that we can give you. As a courtesy, we can offer you some kind of a discount on a replacement programmer - please email us mentioning this thread if you are interested.
Thank you, I think that’s a fair way to resolve an ambiguous case like this.
What would fry just from shorting to ground, though? The only dangling wires I had were vbus (which still tests fine), ground (shouldn’t be a problem), and the A and B lines. Are A and B really capable of sourcing so much current that they’d 'splode the whole chip?