8100 issues

[oldmacs]

Hi All - I've inhertiatd what seems to be a non working 8100/110 - the PSU seems to be fine, but it does not boot. Turning it on by the keyboard or to he power switch lights up the LED, but there is no sound, no video and the hard drives do not read like they are booting (they simply spin up).

Any ideas? I've taken it apart and removed all the Ram but that made no difference.

 

[ArmorAlley]

Without having spare parts, like NuBus graphics cards, NuBus SCSI cards, spare RAM, spare hard discs, I would suggest that you get your motherboard recapped. There are a few in the Fora who can and will do it.

btw, the PDS slot (the one that looks a bit like a 64-bit PCI slot) *must* have something in it. personally, i have a sonnet crescendo g3 400mhz in mine. the faster 24-bit nubus cards run well in these systems.

 

[Bunsen]

First, remove the motherboard battery (if present) and try a double-boot:  leave it powered on for about half an hour, then very quickly turn it off and on again.  Some Macs will refuse to boot without a working PRAM battery, but this trick can sometimes get a little juice into the PRAM circuit and allow it to boot.

If it works, you need a new PRAM battery - 1/2AA 3.6V

 

[Bunsen]

btw, the PDS slot (the one that looks a bit like a 64-bit PCI slot) *must* have something in it.

You sure about that?  I've never had any problems booting a 6100 (same architecture) with an empty PDS.

 

[oldmacs]

Without having spare parts, like NuBus graphics cards, NuBus SCSI cards, spare RAM, spare hard discs, I would suggest that you get your motherboard recapped.

btw, the PDS slot / *must* have something in it

I think there is a graphics card already in the PDS slot. I have nubus cards and spare SCSI Harddrives so I can troubleshoot.

 

[oldmacs]

First, remove the motherboard battery (if present) and try a double-boot

If it works, you need a new PRAM battery - 1/2AA 3.6V

Will try that - the PRAM battery was removed by me when I received the machine. I'm trying to find my charged PRAM batteries to try a working one.

I wasn't aware that any of the PPC macs were dependent upon PRAM batteries - though the 8100 was the earliest PPC.

 

[TheWhiteFalcon]

They're funky. TiBooks, for example, won't boot with a dead one but they'll boot without one.

 

[ArmorAlley]

Hi Bunsen,

I have never tried to boot an 8100 with an empty PDS slot. I read it in a manual, I do believe. If I find it again, I‘ll post you up the link when I find it.

 

[Charlieman]

The 8100 PDS slot must be terminated. This rule also applies to clones.

 

[trag]

The 8100 PDS slot must be terminated. This rule also applies to clones.

True for the entire Nubus Power Macintosh family, x100.  

It may sometimes work without termination, but that's just luck.   PowerMac models which shipped without an AV card or HPV card shipped with a PDS terminator in the slot.  I can't remember if they included the PDS terminator as a loose item with models that included the video cards.

 

[Bunsen]

Huh, I don't think I've even seen a PDS terminator in any of the x100s I've encountered.

 

[trag]

Well, Apple said....

Perhaps it was an Apple engineer just being extra thorough about bus coherency, but in the day there were dire warnings about operating the X100 Macs without some form of PDS termination.  

You've probably seen a PDS terminator outside the slot and just didn't know what it was.  It looks like a DIMM with no components except passives (resistors and caps).

 

[oldmacs]

There is a video card in the PDS slot... still get no life other than the light and fan. I would now assume that its the capacitors? 

 

[trag]

Or cracked CPU.   As long as you're at the take-out-the-logic-board phase, gently pop off the heat sink and check the PPC601 for cracks.  Also, check if the heat sink grease is still fresh(ish).

 

[Charlieman]

Huh, I don't think I've even seen a PDS terminator in any of the x100s I've encountered.

Likewise, but I didn't spend too much time with 8100s at the time when they were current. My guess is that all of the 6100s and 7100s I encountered had a video card or Houdini in the PDS slot. 

There were some Performa offerings (eg 6116CD) which never shipped with a PDS card. An original one of those would demonstrate whether Apple shipped the terminator in a 6100.

My recollection of the 8100's requirement for PDS termination comes from a tech note relating to PowerComputing and Cold Fusion.