Another IIci Thread - No Video!

[Garrett]

I was browsing and have noticed quite a few unresolved threads surrounding video/startup issues with the Mac IIci. My pledge to the forum is that when I solve my own issues, I'll post a follow-up with the solution (if there is one)

I've got a recapped IIci board that has a couple of issues. Firstly the startup circuit - powers up immediately after plugging it in. Pressing the power button causes it to momentarily power down but it'll immediately turn back on. I've verified all traces connecting UB13, UD13, and UE13 have continuity. Next step here will be to replace the chips themselves.

The more pressing issue is that I get a black screen after the chime. Using my trusty Samsung LCD monitor (known to work with the Mac II series), the display "turns on" but screen remains black. If I press the reset button it'll show some garbled nonsense until I release the button. Then it's black again.

It does chime, so I thought that maybe it was actually booting in the background - nope. I tried a BlueSCSI and Floppy EMU. No disk activity on either. I'm very stumped! It's not like the IIsi, where the RBV chip is near caps so broken traces are expected. Chips on this board look clean. I guess I'll have more time with the meter on beep-beep mode to probe stuff out...

 

[speakers]

...

I've got a recapped IIci board that has a couple of issues. Firstly the startup circuit - powers up immediately after plugging it in. Pressing the power button causes it to momentarily power down but it'll immediately turn back on. I've verified all traces connecting UB13, UD13, and UE13 have continuity. Next step here will be to replace the chips themselves.

This startup circuit is relatively straightforward but prone to so many failures. After recapping a badly electrolyte-scarred board, I had a situation where things worked but the machine was left connected to power but soft-shut-down for a day or so, it would refuse to soft-start. I replaced UE13 to no avail. It turned out to be leakage (perhaps via electrolyte and/or short) under cap C13 since the failure disappeared after I removed, cleaned, re-masked, reinstalled C13. This isn't your issue, but there could be a similar mechanism at play.

The more pressing issue is that I get a black screen after the chime. Using my trusty Samsung LCD monitor (known to work with the Mac II series), the display "turns on" but screen remains black. If I press the reset button it'll show some garbled nonsense until I release the button. Then it's black again.

I have a Samsung SyncMaster which is not early-Mac friendly. It completely refused to sync at all with an Iicx's video card and it sometimes stays black when connected to a IIci (sync on green issue?). Anyhow, I'm now prejudiced against Samsung displays.

 

[Garrett]

This startup circuit is relatively straightforward but prone to so many failures. After recapping a badly electrolyte-scarred board, I had a situation where things worked but the machine was left connected to power but soft-shut-down for a day or so, it would refuse to soft-start. I replaced UE13 to no avail. It turned out to be leakage (perhaps via electrolyte and/or short) under cap C13 since the failure disappeared after I removed, cleaned, re-masked, reinstalled C13. This isn't your issue, but there could be a similar mechanism at play.

I think you're right as far as the startup circuit is concerned, I should remove UE13, UB13, and UD13 to deep clean under them. Some sort of short keeping the signal line at +5V would cause it to continually try and power up.

I'm now prejudiced against Samsung displays.

I've had different luck thankfully. Using a real old SyncMaster 171N. VGA into a real basic DB19 adapter (no dip switches). I haven't found a Mac that it wouldn't work with - this includes the Mac IIsi, IIx, and my working IIci. I wonder if there are small differences in your monitor vs. mine?

 

[speakers]

I've had different luck thankfully. Using a real old SyncMaster 171N. VGA into a real basic DB19 adapter (no dip switches). I haven't found a Mac that it wouldn't work with - this includes the Mac IIsi, IIx, and my working IIci. I wonder if there are small differences in your monitor vs. mine?

Mine's a slightly newer SyncMaster T200HD -- which is basically a TV and is fine for my PPC machines with later VGA and DVI but seems to lack coverage for graphics modes of the early Macs.