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#1 2015-08-05 00:19:28

vt4000
Member
From: Seattle, WA
Registered: 2015-08-04
Posts: 2

Performa 6230cd - Bad Cache/ROM DIMM?

Hi guys,

I recently came into possession of a Performa 6230cd.  Everything seems to run just fine under System 7.5.3, but when I go to install Mac OS 8.1, I get the error message:

"The System Software has detected a hardware problem.  Extensions have been disabled.  Please contact Apple customer support or an Apple-authorized service provider to have the Cache/ROM DIMM replaced."

Upon further research, it seems that some of these 5xxx/6xxx series Power Macs had an issue with the Cache/ROM DIMM.  Unfortunately, I can't locate one for sale *anywhere* on the Internet:

Is there a way to bypass this error message and get full OS functionality?  Everything seems to run fine with no crashes or glitches, the only problem is this error message preventing extensions from loading.  Barring that, does anyone know where I can find either one of these or a replacement logic board with one included?

Last edited by vt4000 (2015-08-05 00:24:29)

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#2 2015-08-05 01:08:43

techknight
Member
Registered: 2014-05-22
Posts: 449

Re: Performa 6230cd - Bad Cache/ROM DIMM?

the Cache RAM itself is likely bad. Common problem with older machines.

I dont know of a way to get it working without physically removing the Cache RAM from the PCB.

Last edited by techknight (2015-08-05 01:09:54)

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#3 2015-08-05 01:30:38

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: Performa 6230cd - Bad Cache/ROM DIMM?

Huh.  I've never seen that particular error before, and it triggers a couple questions:
That's a pretty specific error message.  If it's testing the cache, found the cache was bad, disabled it, and then continued booting, why disable extensions?  I guess some extensions may have tried to re-enable the bad cache?  If the cache was actually bad and couldn't be disabled, I don't think the system would have been reliable under System 7.5.x, or booting without extensions.
So I'm wondering if it's actually a test on the ROM its self, and earlier versions had a buggy ROM which needed to be updated for OS8.1.  These machines are notoriously buggy anyway.

Anyway, if you can't find a rom dimm, I can trade yours for mine.

More Info Here

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#4 2015-08-05 02:54:30

LCGuy
Administrator
From: Sydney, Australia
Registered: 2014-05-13
Posts: 819

Re: Performa 6230cd - Bad Cache/ROM DIMM?

Yeah - was a common issue, and Apple had a recall program back in the day. Some of the machines shipped with a buggy ROM. On your Mac OS 8 CD there should be a 5xxx/6xxx Tester that can test your ROM and see if its one of the ones that should have been recalled back in the day.

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#5 2015-08-05 05:38:24

vt4000
Member
From: Seattle, WA
Registered: 2015-08-04
Posts: 2

Re: Performa 6230cd - Bad Cache/ROM DIMM?

Thanks for the insight... I did run the 5xxx/6xxx tester, and it came back with essentially the same message about the Cache/ROM DIMM being bad.  The weird thing is that the original owner took it in for service in '99 and had the ROM replaced. Weird that they didn't replace it with a "fixed" version back then!

bbraun - I sent you a PM.

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#6 2015-08-05 05:47:13

uniserver
Member
From: Sf, Mi
Registered: 2014-05-15
Posts: 956
Website

Re: Performa 6230cd - Bad Cache/ROM DIMM?

if you pop the cache simm out does the message stop, it should run just fine with out the cache simm installed.


#I Re-Cap √Mac √NeTX √Amiga Boards - A/B - PSU# (MacCaps.com)  Modern SCSI HD's - For Old Macs - Pre Cfg'd - 10k RPM! 73gb!! $50 + free shipping  -- Mac 128K Re-Ram kits (16 Chips) $35 + shipping, Floppy Issues?-> Bourns Filter Solution 128k - SE/30, $16 + shipping

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#7 2015-08-11 00:02:51

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: Performa 6230cd - Bad Cache/ROM DIMM?

To follow up, we swapped cache SIMMs, and his seems good to go now.  At some point I'll try poking at the bad SIMM to attempt to understand what exactly the updated SIMM fixed.  Maybe there's some rework that can be done to fix it.

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#8 2015-08-11 05:58:29

uniserver
Member
From: Sf, Mi
Registered: 2014-05-15
Posts: 956
Website

Re: Performa 6230cd - Bad Cache/ROM DIMM?

awesome thanks rob!  i'm curious!


#I Re-Cap √Mac √NeTX √Amiga Boards - A/B - PSU# (MacCaps.com)  Modern SCSI HD's - For Old Macs - Pre Cfg'd - 10k RPM! 73gb!! $50 + free shipping  -- Mac 128K Re-Ram kits (16 Chips) $35 + shipping, Floppy Issues?-> Bourns Filter Solution 128k - SE/30, $16 + shipping

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#9 2015-08-11 15:23:03

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,407

Re: Performa 6230cd - Bad Cache/ROM DIMM?

+1

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#10 2015-08-12 02:57:31

LCGuy
Administrator
From: Sydney, Australia
Registered: 2014-05-13
Posts: 819

Re: Performa 6230cd - Bad Cache/ROM DIMM?

uniserver wrote:

if you pop the cache simm out does the message stop, it should run just fine with out the cache simm installed.

Its been a while since I touched my 6200 (in storage, at my parents' place interstate), but I seem to recall that the cache SIMM also contains the ROMs - there is no onboard ROM.

Anyway, good to see he's back in business. Be interesting to see what the difference is between the "good" ones and the "bad" ones.

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#11 2015-08-13 00:00:51

techknight
Member
Registered: 2014-05-22
Posts: 449

Re: Performa 6230cd - Bad Cache/ROM DIMM?

bbraun wrote:

To follow up, we swapped cache SIMMs, and his seems good to go now.  At some point I'll try poking at the bad SIMM to attempt to understand what exactly the updated SIMM fixed.  Maybe there's some rework that can be done to fix it.

Or its just a bugged ROM firmware itself? Maybe dump it and do a decompile and compare against the good copy.

Last edited by techknight (2015-08-13 00:01:07)

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#12 2015-08-13 00:15:37

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: Performa 6230cd - Bad Cache/ROM DIMM?

I'm not sure yet.  The information I've found leads me to believe it's a bug in how the board handles the cache, but that's just what I gathered indirectly.  If there were a bug in the Mac OS ROM portion of the ROM, they usually just patch around that in software, but I guess it could be a problem with the PPC initialization too.  I'll need to dig into it.

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