Macintosh II Restoration

[Iesca]

Hello!

I've recently acquired a Macintosh II that was upgraded with a Dove MaraThon 030 and fitted with (what I believe is) a Macintosh Display Card 4•8 (empty VRAM slots, Apple Part #: 630-0400), all in a IIfx case. It had two full banks of RAM, but I have no idea what values they are, so I've ordered some (80ns) 256k sticks to put in bank A just for testing purposes. I've also ordered a standard 16MHz 68020 processor, again, just for testing purposes. It does not appear to have had the 68551 PMMU upgrade; I don't know about the FDHD upgrade as yet.

I've replaced the batteries with new Saft 1/2 AAs (battery holder STL courtesy of Bruce Rayne!) and was able to power it on, but other than the fan in the PSU and a small blip from the hard drive (probably a self-test), I do not get any chime or video, though the LED is lit. Additionally, the PSU seems to be a little intermittent (but it stays on once it gets going). If I insert a System Disk when powering on, there is no floppy disk activity.

I plan on replacing the capacitors in the PSU, but it does seem to work for the most part for now. My understanding with regards to the 4•8 card is that it does not work with a VGA monitor, which is what I have currently, using a DB15-to-VGA adapter (dipswitch-less, but it works fine with other machines like my LCIII). But even then, I would have at least expected a chime, although the Mac II Service Source does have a page describing my symptoms ("Symptom Charts/Video" page 7, PDF page 20) as potentially being a monitor issue. And, as can be seen in the photo, there are no electrolytic caps to worry about (apart from some axials, which rarely have issues).

I do not have an Apple CRT monitor, sadly. It would seem that the Apple High Resolution RGB 13" Monitor would be compatible, though I know it is possible for the 4•8 to output higher resolutions to (non-multisync) monitors.

If anyone has any pointers on where to go from here, I'd be in your debt.

And if anyone in the Los Angeles area would like to trade a compatible (and working) Apple CRT for an Apple Cinema Display 22" ADC with DVI adapter, please let me know! Especially if you're near Glendale or Pasadena (I'm in northeast LA).

(Photo of logic board with MaraThon 030 removed.)

 

[Johnnya101]

I saw that on eBay too. Glad to see someone on here got it.

Two things:
1. Are you trying it as in the photo? Without RAM and a CPU, you won't get very far.
2. Some of these PSUs are going bad by now. I wouldn't be surprised if it were dead. Is it an Astec? What do you mean the PSU is intermittent?

If the PSU is on its way out and can't put out enough power, you might be able to remove the hard drive and see what happens.

 

[LaPorta]

The dates on the ROMs lead to a stock II with original (and 32-bit dirty) ROMs. I am assuming that the accelerator plugs in the 020 slot, and that the RAM goes on the main board....but you haven't been testing without then. Would need to know more about the "intermittent" PSU deal as well: if it is like that, and you get a small "blip" out of the HD, that leads me to think that you may be getting low voltages and maybe not enough amps out of the PSU to fire up the HD. I would check the voltages coming out of the PSU, which is very, very easy on this machine with the exposed PSU connector.

 

[Iesca]

Yes, I am of course testing with RAM and CPU installed, the photo is just showing the board for people to get a better look at. That said, a close examination of the RAM slots shows that a couple of the clips in Bank A are not in great condition, so that could be a factor, though I would expect to hear the chimes of death, no?

By "intermittent" I mean that it doesn't always stay on with a quick press of the Power button on the back; I have to hold it in for a bit until it clears whatever hurdle it's trying to in order to get going.

 

[Johnnya101]

That's probably your issue then, a bad PSU. Could be caps, could be something else. Bad RAM would give chimes of death. I would check voltages as LaPorta said if you want to be sure. You can try to unplug the hard drive and see if that changes anything, the old ones use a lot of power.

 

[joshc]

As LaPorta mentioned, what voltages do you get if you take readings from the PSU? Use a multimeter on the pins from the PSU->LB connector. That's where I would start.

Without RAM or with faulty RAM, you'd get death chimes.

Any sound from the headphone port? My IIfx had a dead speaker when I got it so that's a possibility too.

 

[Iesca]

I will measure the PSU voltages and test the audio out port when I have a chance and report back

 

[Iesca]

I've got a chime! With an original '020 processor and known good RAM (with one of the SIMMs secured in place with a rubber band...), I put everything back together and got a chime. The PSU was still a bit finicky, but it didn't seem to matter whether the HD was plugged in or not. Regular boot chime, no chimes of death.

The floppy disk drive does not accept my 6.0.8 System Tools (known good, still works in my Plus), and also spit out other 6.0.8 disks. The drive heads have been cleaned. The Hard drive just goes 'bzzt', which makes me think that the rubber bumpers have melted, preventing the head arm from moving (it's a Quantum drive).

Still no video of course, but this is promising! And I didn't even have to measure the PSU voltages.

 

[LaPorta]

I'd still measure the voltages to be sure, but glad you got the chime! Maybe your accelerator card is not working well.

 

[Iesca]

Maybe! I discovered to my dismay that it has a broken pin on it, but upon further investigation, I discovered images online of other units with the same exact pin broken off, which leads me to believe that it was deliberate on Dove's part back in the day.

 

[Iesca]

The Mac II lives!

Having swapped out the accelerator for an original '020 processor, I also acquired a Samsung MacMaster video adapter (set to multisync) and was able to get it to work with a modern VGA LCD monitor! I also upgraded the video card, a 4•8 card, to an 8•24 with two 256kb VRAM modules, but other than some additional gamma options (which don't seem to matter for an LCD display), I don't have any more resolution or color options, at least in System 6. Curiously, the last nubus slot does not seem to work, but at least the first one does; haven't tested the others. The hard drive and floppy drive were still unresponsive, but I used an external SCSI hard drive with System 6 and everything is running swimmingly.

Speaking of "SWIM", it turns out this Mac II also had the SuperDrive upgrade! The internal floppy was a Sony 2MB, and it has the correct chips for the SWIM floppy controller (344S0062) and the upgraded ROMs (342-0639, 342-0640, 342-0641, & 342-0642). I've also upgraded the HMMU to a 68851 PMMU. Unfortunately, unless there's something I'm missing, the accelerator seems to be kaput, as there still isn't even a chime when I power on with it installed.

With regards to the original floppy disk drive, I did try swapping it with an 800k drive, and while that one "works", I think it has its own problems that are resulting in issues using floppies. The SuperDrive should be able to read 800k disks, shouldn't it? I didn't test it with a 1.4 MB disk, but I'm guessing it wouldn't matter. I did previously clean the drive heads, but that didn't make any difference.

 

[joshc]

The SuperDrive should be able to read 800k disks, shouldn't it?

Yes

 

[Iesca]

That's what I thought, I just didn't know if perhaps there was something about the SuperDrives used in Mac II's that I didn't know about. Thanks!