Non-booting Macintosh IIci, looking for some ideas

[spiceyokooko]

I rather suspect the answer to this will be what I expect, but I think it's worth asking the question just in case there's something I've either missed or over-looked.

I'm having problems getting a Macintosh IIci to boot and get past post. I've gone over all the likely causes several times, but I'll start with a few knowns -

- The PSU is known to be a working one - I've tested it in a IIcx and it boots it fine without problem.

- The RAM SIMMS (4 x 4 Mb in bank A only) are known to be good and work as I've tested them in the IIcx, I've also checked and rechecked they're seated correctly. I've also tried other known working 4 x 1Mb SIMMS too.

- The HD is known to be good as I've booted from it in the IIcx, it's correctly terminated and set to ID 0, there are no other devices on the SCSI chain.

- The PRAM battery is brand new and known to be good as it works fine in the IIcx and Mac IIx, I've also checked its output on a multimeter.

- The display is known to be good and works fine in the IIcx

- The nubus Video board is known to be good and working as it works fine in the IIcx.

I've completely dismantled the whole box and water/soap washed and then iso alchohol washed the board and allowed it to dry then reassembled the whole machine double checking all the connections.

So here's what happens when I try to boot the machine - the PSU fires up no problem and the HD spins up and starts working and I get the chimes of death - the display stays black.

I've swopped in a 512k ROM from a Mac IIx and switched the display connection from the nubus video board to the onboard video and the PSU fires up, the HD spins up and the display comes on but is plain mid/light grey with nothing else on it - but no chimes of death.

I'm now out of ideas as to what else it can be apart from a problem on the logic board. I've looked closely at the capacitors and there's no signs of bulging and saw no evidence of electrolyte on the board prior to washing it. It's possible of course the capacitors have failed and need replacing, but I wanted to explore all possibilities before doing that.

Does anyone else have any ideas?

Cheers!

 

[bibilit]

I will try with a minimum setup:

Onboard video only and Nubus video removed.

No HD (try to boot from a floppy) and see what happens.

 

[spiceyokooko]

Thanks for your suggestion.

I've tried that - same result. The psu fires up, the screen comes on to a mid grey screen and then nothing.

It's failing its hardware checks at startup and therefore not even getting to the point that it's looking for a system. What's curious is that using the on board video rasterises the screen, yet using a known working nubus video card doesn't. It all points to a problem on the logic board for me.

Cheers!

 

[Trash80toHP_Mini]

I think you've isolated your problem. I've got finicky PowerBook that shows the same symptoms most of the time, but it boots periodically. It shows the same gray screen on the video out connector's display.

 

[trag]

When you tried using a ROM SIMM, you needed to remove the jumper next to the ROM socket. Did you do that? I'm not sure it would work, even so, as I've never heard of anyone using a ROM from an earlier model in the IIci. Nevertheless, that's a reasonable way to test whether the traces to the on-board ROM chips have problems.

Hmmm. Come to think of it, was the jumper *installed* when you tried it without the ROM SIMM? That jumper needs to be in place.

I agree with the earlier poster who said to try it with no hard drive connected. At this point you just want a good bong and a gray screen with a flashing floppy image and question mark. You don't need a hard drive or a floppy drive for that.

 

[spiceyokooko]

Hi trag thanks for your input.

Interestingly, the Macintosh II, now that I've soldered in two new PRAM batteries, (this is an old one that had soldered PRAM batteries) is doing exactly the same thing as the Macintosh IIci. The PSU is firing up, the monitor is rasterising to a light/mid grey screen and then nothing.

The only conclusion I can come up with for both of them is they need new capacitors.

Thoughts?

 

[trag]

The only conclusion I can come up with for both of them is they need new capacitors.
Thoughts?

It could be, but it is not a certainty.

Or let me put it another way. All of these model of Macs need new capacitors. But, that may not be the cause or the only cause of your problem.

My IIci needed new caps back in the mid-90s. But, not only did the caps give out on me, the goo from the caps ate through a via (pass through hole in circuit board) on the logic board which connected a front layer trace to a back layer trace. The damage was not at all obvious and it required examination with a magnifier and then testing with a multimeter to identify. Once I found it, it was easy enough to bypass with a little bit of wire.

But I would never have known to look, if someone had not posted about this kind of problem in the news groups back then.

I think that our user, Dennis Nedry, had some traces to his ROMs damaged by capacitor leakage, but I may be misremembering.

So, replacing the caps has a good chance of fixing the problem, but it might not.

 

[techknight]

its either ROM or RAM damaged connections. usually instant chimes of death with slightly slower play, the system failed the RAM check in the system heap area, right from the very beginning of RAM. the system heap must be initialized before it can even think about displaying a sadmac RAM code.

 

[spiceyokooko]

trag and techknight thank you both for your input.

I've looked quite closely at both logic boards when I was cleaning them and I see no evidence of either leaked electrolyte damage or damage to any of the pcb connections. That's not to say there isn't any there, I just don't see any. Neither did I see any evidence of failed or failing capacitors, but again that's not to say they haven't or aren't failing.

I also find it rather curious that both non-working machines, the IIci and II are both showing identical symptoms, the psu firing up, the screen rasterising and then nothing. That does rather suggest that whatever the problem is, is affecting both machines.

I'm not sure where that gets us really!

Cheers!

 

[Dennis Nedry]

If I recall correctly from my experiments, the IIx ROM does exactly that in a IIci - gray screen - so I would rule out using the IIx ROM right away. It might work in your IIcx but I wouldn't count on it in the IIci. The machines are very similar but they are in fact different in some ways when you start swapping things between them.

Did you try connecting the display to the onboard video and without the IIx ROM SIMM installed? That's an important test.

When you say that the hard drive "spins up and starts working", does this mean that it started making sounds like it was loading something off of the drive? If so, that would mean the IIci has trouble with loading the OS. It is completely possible that the exact same hard drive will death chime on a IIci and not on a IIcx -- for example, system 6.0.3 works fine on IIcx and not at all on IIci. If this is happening, it is conceivably a separate issue from the black screen.

The test for OS-related death chime is to disconnect the HD and see if it still death chimes.

Also, does it make the normal startup chime at first?

The fact that your IIci makes sound and responds to the power button properly is evidence that your caps are still pretty good.

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As for the Mac II/IIx, if this was the source of your ROM SIMM, did you remember to put it back in there before turning it on? I think it'll do something like you described without that in there.

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trag: I had a IIci logic board that was badly scratched through a number of traces, and one additional trace underneath the battery holder was corroded open from a very slight battery leak. Also very bad, messy caps on that Mac.

 

[spiceyokooko]

Hi Dennis, thanks for your input into this.

If I recall correctly from my experiments, the IIx ROM does exactly that in a IIci - gray screen - so I would rule out using the IIx ROM right away.

I tried the II ROM simply because all else had failed, without it in, the machine simple came up with a black screen rather than a grey one.

Did you try connecting the display to the onboard video and without the IIx ROM SIMM installed? That's an important test.

Yes I did. First I tried the display connected to the nubus video and then to the onboard video. The results were the same - both black screens, yet with the II ROM I got a grey screen from the onboard video.

When you say that the hard drive "spins up and starts working", does this mean that it started making sounds like it was loading something off of the drive?

No, the drive merely 'spins up' and starts working, it was not making the usual clicking noises as if it was accessing the disk to read information from it.

The test for OS-related death chime is to disconnect the HD and see if it still death chimes.

Unfortunately, the machine still death chimes with the HD and Floppy disconnected.

Also, does it make the normal startup chime at first?

There's no startup bong/chime.

The fact that your IIci makes sound and responds to the power button properly is evidence that your caps are still pretty good.

Well that would tie in with my visual inspection of the board. I just don't see any damage from leaking capacitors, I see no breaks in the connections and I see no evidence of the capacitors leaking or bulging - the capacitors look nice and straight.

----------

As for the Mac II/IIx, if this was the source of your ROM SIMM, did you remember to put it back in there before turning it on? I think it'll do something like you described without that in there.

Yes, the Mac II was failing to start before I pulled the ROM simm out to try in the IIci.

I will double check all of this again just to make sure what I've said here is correct from memory. The use of the ROM simm is just a bit of a red herring I think as it was only tried after all the other attempts to get it started were tried. What I found curious about the ROM simm being in there was the change of screen colour from black to grey, but again from what you've said that's fairly inconsequential as things go.

Putting the use of the ROM simm to one side, as it stands at the moment, whatever I do or whatever I try results in the chimes of death and a black screen. One thing I did notice when I inspected the board were a couple of bent over pins on the processor, they wern't touching each other and the connections seemed intact and undamaged, so I think mentally I put it to one side. But I guess that might be significant? I should re-inspect that area for any other damage I think.

 

[Dennis Nedry]

A death chime before the startup chime - I think that's our biggest clue at the moment. There's something setting a sad mac before the video gets initialized. RAM verification and ROM checksum are the only 2 things I can think of. ROM checksum could fail because of actual damaged ROM (unlikely) or damaged higher address lines to the ROM. We know that low address lines and all data lines are okay to the ROM because it successfully plays a death chime. But I really don't think it's ROM-related at all, that would be really bizarre.

I think I'm with technight and leaning toward something RAM-related. There's no other particularly fixable alternative that I can think of. I guess you could try cleaning the RAM fingers and slots and replacing the caps but I'm pretty much at a loss otherwise. Actually, you might be able to apply pressure in various directions to each RAM SIMM to see if you get a temporary good connection. Also, pressing on chips on the logic board, etc. But it's all just reaching for clues at this point.

 

[techknight]

its bad/dirty connections in the SIMM sockets, broken traces, or bad DRAM timing control circuitry (VLSI, etc..) I could guess for hours, but thats my top guesses.

 

[applefreak]

First try PRAM reset

 

[Bunsen]

Random thought - try swapping the known-good RAM into bank B. That would eliminate bad traces to bank A.

And yes, as Applefreak reminds us, one should always hold down the motherboard PRAM reset button for a count of 30 when one has swapped hardware around.

 

[spiceyokooko]

First try PRAM reset

Hi Applefreak, thanks for your suggestion.

I pretty much pull the PRAM battery out each time I've finished working on the machine, which effectively resets the PRAM, but I'll certainly try the keyboard reset route, thanks for the thought.

 

[spiceyokooko]

Random thought - try swapping the known-good RAM into bank B. That would eliminate bad traces to bank A.

Hey Bunsen, thanks for your input.

I've tried starting the machine with the only RAM in bank B, and get the same result. But that was back when I first started trying to get the machine working, it's well worth trying again now as well, so thanks for that suggestion.

 

[Dennis Nedry]

Bunsen, I read somewhere that you are only ever supposed to press and release PMU reset buttons and that holding them down for a period of time is not recommended and/or could corrupt the power manager again. I believe that it was form Apple but I can't cite my source ATM.

PMU reset is a power manager reset, not a PRAM reset. Also, some Macs such as the IIci and even the 6100, don't have a PMU reset button. From what I gather, the button specifically fixes soft power issues.

 

[Bunsen]

I've read conflicting suggestions there, too, Dennis. But does a IIci even have a power manager? I thought that was a Powerbook thing.