Michael J. Mahon wrote:
jonnosan wrote:On May 12, 3:53 pm, Silicon Sam <Silicon...@gmail.com> wrote:On May 11, 11:21 pm, jonno...@gmail.com wrote:> Howdy folks,I recently bought an apple iie off ebay (it's my first apple ever - we had BBC's at my school)Unfortunately when I unpacked the apple and plugged it in, it seemed to be DOA - the screen was always a periodically changing jumble of blocks (photo athttp://www.flickr.com/photos/jonnosan/494345448/). keypresses made no difference, nor did pressing reset (alone or in combination with other keys)I seem to recall, it has been a long time ago, but it may have something to do with the keyboard. Make sure it's plugged in right, and try it with it unplugged. I think that block pattern is actually a test mode Apple used when testing motherboards in a rack. While this block pattern is going on, does the speaker make any kind of noise? There is also an LED at the back of the motherboard that is tied to the speaker circuit as well. This was so Apple could set a few hundred motherboards in a rack, power them up with power only, and observe the LED. When the LED was out, the test failed for that board..I've tried it with the keyboard plugged in, and with it not plugged in, and it seems to make no difference. If I leave it turned on, after about 30 seconds there are some blips that come out of the speaker, and an LED (not the power LED, so might be the one you refer to) flickers briefly, and the pattern on the screen changes (it's still random blocks, just a slightly different arrangement).There is nothing wrong with either main board. That's the self-test running. If it keeps running, it should also display "System OK" in the middle of the screen for a few seconds on each cycle. There is a problem either with your keyboard if it is plugged in correctly.
Sorry, bad edit--scratch the "either" in the above sentence. ;-)
In particular, if the keyboard is plugged in and the Closed-Apple key is depressed while the unit is powered on (or reset), the self- test will execute. If, in addition, the Open-Apple key is depressed, the self-test will cycle endlessly. If the keyboard is unplugged, or if the wires to PB1 and PB2 are not "pulled down" to ground by 470-Ohm resistors on the keyboard, it will "look" to the computer like both switches are depressed. The simplest explanation for the behavior you are observing is that the keyboard ground wire (pin 13 of the connector) is broken, either at the IDC connector (from being pulled by the wire, for example) or somewhere along its length. (This would also explain why Reset doesn't do anything.) If you have an ohmmeter, check for continuity between a ground trace on the main board and a ground trace on the keyboard, then shorten the path until you isolate the "open". -michael NadaNet file server for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."
-- -michael NadaNet file server for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."