Macintosh IIci motherboard no video

[JRL]

So a while back, I received a bare Macintosh IIci motherboard. No RAM, and an old battery.

I replaced the old battery with a new one and put in x4 2 MB SIMMS.

When I turn the power supply on, I don't get any display from the built-in video at all. Note that I don't have an internal speaker hooked up so I can't hear anything.

What should I do? Thanks!

[waynestewart]

When they stripped the IIci maybe they took the ROM jumper at W1. Without it you won't get any video.

Wayne

[JRL]

I'll check that location. Thanks!

BTW, no VRAM stick is necessary, right?

And also I'm using 100 ns RAM. Will that work?

[JRL]

Well, I just read that 100 NS RAM (aka LC/LC II series RAM) won't work on the Macintosh IIci.

Will the IIci give video without RAM?

[Charlieman]

There are lots of possible problems here.

System RAM needs to be fast (off the top of my head 80ns -- correctly guessed) and 2MB SIMMs don't work. You have to have functioning RAM for the Mac to boot enough to display anything on screen -- there's no VRAM.

The monitor has to sync nicely with the IIci built-in video card. Few monitors do.

For feedback on booting, you should get some indication just by putting your small fingers on top of the disk drive. Or try booting from a floppy disk -- anything with a system file should give audible feedback from the floppy drive.

[JRL]

The monitor I'm using is the Macintosh '12 RGB. I do have a Apple Color Plus '14 display which as for as I'm aware of works with the IIci (or am I mistaken?)

I also have x4 1 MB SIMMS but they were from a PC so I'm not too sure of compatibility.

[GreenDoc]

Its a shame I let the RAM I had go along with the IIci board I sold a little while back.

[equill]

… The IIci uses DRAM for video and maps it to Bank A. Contrary to other Macintosh models, always install the lowest density SIMMs in Bank A for best performance.

As Charlieman suggested, 80ns RAM is needed. If you have no video card in place, onboard video needs Bank A (two right-hand pairs) DRAM to work (so-called 'Vampire Video'). Your total DRAM, depending on your installed System, may then be perilously low. (The IIci can support up to OS 7.6.1 on a 68030 if it has enough RAM, which can be up to 128MB.)

… On-board video support for 12” B&W, 13” RGB, and 15” B&W Portrait monitors …

Various third-party and Apple NuBus video cards can give a wider choice of displays, and also obviate the use of DRAM for video with their on-card VRAM.

When they stripped the IIci maybe they took the ROM jumper at W1. Without it you won't get any video.

Nor anything else, for that matter. That jumper selects between on-board ROM and the ROM slot. There never was a ROM card for the IIci, so the on-board ROM must be selected. Otherwise the IIci behaves all-same hearthstone. No ROM = no startee. Nix. Nada.

… Parity is generated by the optional Parity Generator Chip (PGC). If you want parity checking you must order the Macintosh IIci configured with the PGC and nine-bit DRAM SIMMs.

The (scarce) parity-checking version of the MLB obliges you to use (9-chip) parity SIMMs (but still 80ns or faster). If there is no Parity Generator Chip to the left of the DRAM slots of Bank B, but only the naked solder-pads, this is not a concern. You can use parity SIMMs in a IIci without a PGC, however, because the ninth chip will be ignored by the System. If you do not have a video card, you could probably use the 4 x 1MB in Bank A and the 4 x 2MB in Bank B (you are fortunate that the IIci is one of the few Macs that will use 512kB and 2MB SIMMs, but not 8MB) to get around Vampire Video effects.

de

[JRL]

I tried equill's configuration (x4 1 MB in the first bank, x4 2 MB in the second) but with no change.

I will try the Apple Color Plus '14 next since I think Macintosh IIcis will work with that monitor.

[trag]

I tried equill's configuration (x4 1 MB in the first bank, x4 2 MB in the second) but with no change.

I will try the Apple Color Plus '14 next since I think Macintosh IIcis will work with that monitor.

The Apple Color Plus worked for me back in the early 90s. I used to use it on my IIci's built-in video until I got a video card for it.

However, the ACP is subject to a fuse blowing problem. A lot of them had it. And mine eventually died by blooming the screen to either super bright or super contrasted. There was probably one bad component in there that needed fixing, but by that time we were ready to switch to LCDs. I still have a 14" viewsonic around here that will work with it though.

[JRL]

Alright, thanks!

Good thing mine works fine.

Also trag, do you know if the Macintosh '12 RGB display (the one that came with the LC/LC II) will work with my Macintosh IIci motherboard? Thanks!