Macintosh IIci with no video/display chime of death

[DistantStar001]

Much as the title says. I bought three Macintosh Iici's and a spare motherboard from a local recycler and have been trying to piece together some working machines out of the parts. So far I've got one, but am working to piece together a second.

I have a good case, but the previous boar had a battery explosion. The new board looks good enough, but needed a recap (surprise I know). In any case, I cleaned and recapped it, installed a new PRAM battery, and gave it a test. The power light turns on, I get a happy boot chime, then about 10 to 12 seconds later... The chime of death. Also, there is no video coming out of the machine. Either from the motherboard or the NuBus video card.

Unfortunately i am working from a LCD VGA display but it does work with the other Iici.

Any ideas?


Update: Video might be fixed (but probably not). Had a wire crossed. Now I get a picture from the NuBus card (E-Machines logo comes on after chime of death), but not from the board.

 

[finkmac]

do you have RAM installed? if so, which bank?

 

[DistantStar001]

do you have RAM installed? if so, which bank?

Yes. Bank A.

 

[nathall]

This sounds exactly like what my IIfx has been doing for the past couple years. I have not been able to track down the issue as of yet. The delay after the bong indicates the failure is happening after the RAM test. I BELIEVE the issue in my case has something to do with the ADB circuit. I found a broken trace in this circuit, but I haven’t yet been able to determine what two components it is connecting as it disappears underneath things. The machine also won’t start from the keyboard or reset when the reset key combo is pressed.

Does the IIci reboot if you press the reset key combo after the death chime?

 

[DistantStar001]

This sounds exactly like what my IIfx has been doing for the past couple years. I have not been able to track down the issue as of yet. The delay after the bong indicates the failure is happening after the RAM test. I BELIEVE the issue in my case has something to do with the ADB circuit. I found a broken trace in this circuit, but I haven’t yet been able to determine what two components it is connecting as it disappears underneath things. The machine also won’t start from the keyboard or reset when the reset key combo is pressed.

Does the IIci reboot if you press the reset key combo after the death chime?

No. But soft power does work from the keyboard.

 

[DistantStar001]

Fixed! ONE CORRODED PIN ON THE CPU!!!! Facing to the back and closest to the power connector. The one next to it is also corroded a bit, but thankfully intact. I managed to get a very sloppy bodge on it (my hands shake) but it works. At some point [MAYBE] I will replace the CPU when I have a proper hot air gun and a fresh and working 68030 CPU. But until then, I'm putting a floppy drive in it and looking for a SCSI replacement as this Macintosh Iici lives again!