Hello everyone,in free time I keep banging my head with the beloved Apple IIe that will not start ...
the situation is this: there was some capacitor .1 short .... I changed them all ... the processor receives the clock ... 6502 ... 1MhzHowever, there is no reset on startup .... or rather there is only if I press the reset from the keyboard ...
the situation remains unchanged .... no video, no beep LED on the motherboard and keyboard on. the manuals ... it is assumed that the fault of the IOU .... tips? thanks Il 19/04/2013 03:06, Michael J. Mahon ha scritto:
David Schmidt <schmidtd@my-deja.com> wrote:On 4/17/2013 11:17 AM, barrym95838 wrote:http://www.willegal.net/appleii/appleii-repair.htmNice link, schmidtd; that's just the kind of thing that I was starting to look for, to help Danilo get his Apple out of its coma!I'm currently going through the same thing with two comatose boards: they are US rev 3 and rev7 boards. I'm working on the rev 3 now. Since I have no digital tools, I am down to thinking and swapping. So far I have done full-board chip swaps with a known-good rev 3 board (one row at a time, including CPU), and I replaced all 3904 transistors. I consistently get a typical memory pattern display on power-up, so at this point I'm still suspecting lack of reset-ability. (The keyboard reset key does not in fact reset it.)Actually, checking for a functional reset is near the top of the list for a non-functioning processor. And an open 0.1uF bypass capacitor can incapacitate :-) a processor. I had a machine that wouldn't beep until the (subtly) broken decoupling cap adjacent to the processor was replaced. (It had one lead almost invisibly cracked as a result of several Zip Chip insertions and removals.) -michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon
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