Hi all,
I've recently come into possession of a non-functioning 41c. I have read a good amount of the available online repair guides and I feel like I'm getting my head around the issues. But I'm stuck and would be happy to hear your considered advice.
I have disassembled the unit. It took me some time to realize that those two 0.15" nuts (!!) screwed onto the lower CPU board posts were someone else's repair attempt. Both upper posts are cracked. The lower ones look alright (not cracked, that is) except for the threads cut by the 0.15" nuts. If you squeeze the two case halves together you can get the screen activated but it only (alas!) shows jibberish. Incidentally, the unit is in excellent cosmetic condition and the battery compartment, in particular, and contacts look very good.
I've considered rebuilding the upper posts and keeping the nuts on the lower ones to see if that would do it -- but I'm skeptical that it would. I would have thought that by squeezing the two case halves together (firmly but accurately) at the upper and lower post points I'd be able to see something sensible on the display when turning it on. Can anyone comment on this point? Shouldn't squeezing by hand do it?
The next step, I suppose, is to cut out the middle-man and just go ahead and solder wires between the pressure contacts. But this seems like some good amount of work. And, being a pessimist, I'm assuming the electronics are fried anyway.
My question is: does anyone know how to check the chips? Can't I use a digital multimeter to check point-to-point resistances or voltages and compare to a chart of expected values? I'm stabbing in the dark here, clearly. But I think there should be some way to do this.
Your advice and comments are most welcome. Let me know if I should try something else. (I'm hoping to fix it myself -- sorry FixThatCalc -- or chop it for parts.)
Thanks in advance.
Mark