I have tried the machine now with the following config:
I verified that all of the keyboard connections are good between the keyboard end of the cable and IC3/IC32.
I have tried with the keyboard connected and tried both of my available 6522 chips, but still no luck. Just the system hanging with a flashing cursor.
I can observe weirdness in the capslock/scroll lock LEDs - they are sometimes responding to a keypress and other times they are not. As these are controlled by IC32 and also earlier guideance on this thread I think I should turn my attention to that chip. I checked it with an oscilloscope and can see that S0, S1 G, and D all have binary activity but S2 is held permanantly high.
I am wondering if I remove it, should the system be able to function without it, or maybe I may as well wait until I am able to get some replacements ordered? I am sure it can funtion without the keyboard LEDs of course, and I can see that IC32 is also connected to the sound chip at IC18 and also IC99 which is not fitted. So I think it should be OK?
Thanks!
Nic
Code:
REMOVED - IC69 - User 6522 VIAREMOVED - IC78 - 8271 chip or 1770/2 disk interface moduleOS ROM - IC51 - ROM/EPROMBASIC - IC52 - ROM/EPROMREMOVED - IC88- ROM/EPROMREMOVED - IC100- ROM/EPROMREMOVED - IC101- ROM/EPROMNOT FITTED - IC89 -68B64 EconetREMOVED - IC7 - Serial ULA 2C199FIXED - IC4 - 6850 serialREMOVED - IC73 - uPD7002 analogue to digital converterREMOVED - IC98 - TMS6100 speech system chipREMOVED - IC99 - TMS5220 speech system chipS9 - openS21 - nw to ne AND sw to seS25 - tried bothI have tried with the keyboard connected and tried both of my available 6522 chips, but still no luck. Just the system hanging with a flashing cursor.
I can observe weirdness in the capslock/scroll lock LEDs - they are sometimes responding to a keypress and other times they are not. As these are controlled by IC32 and also earlier guideance on this thread I think I should turn my attention to that chip. I checked it with an oscilloscope and can see that S0, S1 G, and D all have binary activity but S2 is held permanantly high.
I am wondering if I remove it, should the system be able to function without it, or maybe I may as well wait until I am able to get some replacements ordered? I am sure it can funtion without the keyboard LEDs of course, and I can see that IC32 is also connected to the sound chip at IC18 and also IC99 which is not fitted. So I think it should be OK?
Thanks!
Nic
Statistics: Posted by nicf82 — Sun Dec 08, 2024 4:36 pm