My Macintosh IIci: New Logic Board, New Problems

[sadmanonatrain]

Hello all,

A new logic board arrived from Chicago for my Macintosh IIci. I promptly cleaned it and replaced all of its capacitors.

The startup sequence follows as thus:

Press power button --> Startup Chime --> Gray screen (without floppy icon) --> Chimes of Death (still on gray screen)

I've tried various things to remedy the problem such as minimal setups (no cache card, floppy drive or HD), RAM in different banks, with/without a video card and using RAM that is known good.

The fact that the IIci Chimes suggests that hardware and software are good. But I can't understand why the Death Chimes play!

Any help would be much appreciated!

 

[Sebastian]

Hello all,
A new logic board arrived from Chicago for my Macintosh IIci. I promptly cleaned it and replaced all of its capacitors.

The startup sequence follows as thus:

Press power button --> Startup Chime --> Gray screen (without floppy icon) --> Chimes of Death (still on gray screen)

I've tried various things to remedy the problem such as minimal setups (no cache card, floppy drive or HD), RAM in different banks, with/without a video card and using RAM that is known good.

The fact that the IIci Chimes suggests that hardware and software are good. But I can't understand why the Death Chimes play!

Any help would be much appreciated!

did you measure the ram-sockets to the adress muxes?

 

[sadmanonatrain]

Hello all,
A new logic board arrived from Chicago for my Macintosh IIci. I promptly cleaned it and replaced all of its capacitors.

The startup sequence follows as thus:

Press power button --> Startup Chime --> Gray screen (without floppy icon) --> Chimes of Death (still on gray screen)

I've tried various things to remedy the problem such as minimal setups (no cache card, floppy drive or HD), RAM in different banks, with/without a video card and using RAM that is known good.

The fact that the IIci Chimes suggests that hardware and software are good. But I can't understand why the Death Chimes play!

Any help would be much appreciated!

did you measure the ram-sockets to the adress muxes?

Sebastian,

I don't quite know what you mean but does it involve this page?

http://68kmla.org/wiki/index.php/Macintosh_IIci_RAM_and_ROM_Pathways

Or maybe the startup circuit?

http://home.earthlink.net/~gamba2/images/macIIcisch.GIF

I'm a bit of a novice in some respects!

Thank you for the reply!

 

[beachycove]

I've no idea what that meant, either.

It sounds like it could well be a RAM problem, though you do report that the RAM is good. In what machine was it tested?

Two things to check:

1. Is your RAM the right speed? RAM has to be 80ns or faster in the IIci. This page is useful: http://www.jagshouse.com/ram_guide.html .

2. Also, occasionally a particular IIci will require parity RAM. Google that.

 

[Ike]

Ok, tested some things.

If lets say you don't have the ram installed of pairs in four identical SIMMs, it chimes, but then directly after that it gives a sad mac with chimes of death.

Now if a ram chip were to be bad, I would think that that would be become visible during any ram counting right? That would explain any waiting/pause between the chime and the chime of death.

The Ram muxes are the little chips that are somewhere near the ram sockets... Just took a peek into my IIci and my guess would be the four chips on top of the ram sockets, they had a silkscreen line around them. Now since I only had access to the schematics of the SE/30, which is essentially a IIx -> IIcx one would think that it is the same for a IIci, but it's not quite sadly, so someone has to verify.

 

[sadmanonatrain]

beachycove,

I am using the 4*2Mb SIMMS that originally came with my IIci. They have been tested in a Quadra 950 and they work fine. I believe that they are of the correct speed because 80ns or faster is the minimum speed required for the IIci and the 950.

I don't think my Iici is of the parity RAM variety.

Ike,

The RAM muxes must be the four chips marked 'MM030T 74F245'

The RAM must be good if the IIci Chimes!

Thank You!