Hey all,
Got back to the IICX repair project(s) today and I have some more parts, components, and new discoveries and could sure use some help if anyone is up for it.
So Since my las post I have acquired and repaired an AppleColor RGB monitor that I can use on the bench for troubleshooting the IICX boards.
I've also got a Powerbook 180 that I used to repair the monitor. The picture looks perfect now.
Next, I have two more IICX boards and I am focusing on the one in the best shape now.
Heres the rundown of the boards:
Board A - This is the one we have been troubleshooting and left off with it having a clock but no activity on the bus. No signals on the ROMS and had lifted the UC9 - 13 and UD 9-13 chips. I have set this board aside for now.
Board B - This one is in pretty good shape. It powers up and makes a sad mac chime. It has data and address signals all throughout the board but there is no activity on any of the NUBUS pins. I am focusing on repairing this board.
Board C - This one suffered unrepairable damage to the front right area around where the battery is located. I have never seen damage this bad before. So bad that the battery holder had corroded and fallen off the board along with a bunch of chips. both side have major damage in this area but the rest of the board looks good so I can use this as a donor board for parts.
So on with Board B...
The first thing I tried was hooking the two video cards I have up and no picture on the screen with either card so I began probing with the scope...
My findings so far are:
UH2 -
• No signals at A15 (pin 2&5).
• No signal at A16 (pin 10&13) except while the sad mac chime is playing, then i have some activity.
• No signal at A17 (pin 11&14).
• No signal at RAA7 or RBA7 (pin 9&12)
• There are signals on the rest of the pins except 8,15(GND) and 16.
UJ3 -
• No signals at A18 (pin 3&6).
• No signal at A19 (pin 2&5)
• No signal at RAA8 or RBA (pin 7&4)
• There are signals on the rest of the pins except 8,15(GND) and 16.
UC8 (FPU) -
• signals on D0-31 look good.
UG8 (NUCHIP)
• A0 - 31 - no signals except pin 81 & 4
• pin 50 = LOW
• pin 49 = HIGH
• pin 70 = HIGH
• pin 55 = LOW
• pin 48 = HIGH
• pin 57 = LOW
• pin 78 = HIGH
• pin 77 = HIGH
• pin 44 = HIGH
• pin 47 = HIGH
• pin 52 = Has a signal
• pin 45 = LOW
• pin 69 = LOW
• pin 79 = LOW
• pin 46 = HIGH
• pin 67, 66, 65, 64, 62, 61, 60, 59 = LOW
• BERR (pin 13) = HIGH
• HALT (pin 15) = HIGH
• BR (pin 16) = HIGH
• DSACK0 (pin 22) = Has a signal
• DSACK1 (pin 21) = Has a signal
• SIZ0 (pin 28) = Has a signal
•SIZ1 (pin 27?) = LOW
• AS (pin 29) = Has a signal
• R/W (pin 30) = HIGH
• DS (31) = Has a signal
• ARST (pin 32) = HIGH
• BG (pin 41) = HIGH
• CK (pin 68) = Has a signal
• BGACK (pin 75) = HIGH
• RMC (pin 80) = HIGH
• FC1 (pin 84) = Has a signal
• PAS (pin 10) = Has a signal
Thats about all I have checked at this point and kind don't know where to go next.
If anyones got some suggestions I would appreciate it a lot!
Hoping to get at least one of these boards running! lol
** I should expect to see some activity on the NuBus slots right?
Thanks!
-Tavis