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mtm84

Powermac 9600 G3 problems

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Off and on reader, brand new user here.

 

I have a 9600/200 with a powerlogix G3 900/512k upgrade that has been giving me some trouble.  I recently dug it out a few weeks ago after putting it away in... 2005ish?, and it just does not like to boot up with the upgrade card installed.  Boots fine with the original 200mhz 604e, but for cost and rarity reasons I don't want to give up on the upgrade or get a replacement.  So I'm asking for help in isolating the cause.  Did the card go bad?  Bad caps on the motherboard?  I didn't see any obvious signs of leakage but could be.  Bad drivers?  I don't think so since 1 time out of 20 the machine does boot up. Ive tried it with the original twin turbo and a R9000 ME, with the same twichy results.  Any ideas would be appreciated.

Edited by mtm84

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What kind of errors do you get?

  • Do you get a boot chime when it fails to power up?
  • If so, how far does it get into the boot?
  • How much RAM are you using, and have you tried installing only the minimum possible, using the fastest (based on refresh rate) dimes you have?

More details would be appreciated.

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59 minutes ago, defor said:

What kind of errors do you get?

  • Do you get a boot chime when it fails to power up?
  • If so, how far does it get into the boot?
  • How much RAM are you using, and have you tried installing only the minimum possible, using the fastest (based on refresh rate) dimes you have?

More details would be appreciated.

 

I think it could be a ram issue.  or a ram bank issue, I'm still trying different setups.  The main error i would get is a chime and then freezing on the happy mac before loading the OS splash screen, tho occasionally I would get to the splash screen and then it would freeze, ususally before any extensions loaded and sometimes with a garbled screen.  I don't remember exactly what ram is in it, I have 512 megs using 4 128meg dimms, I bought them years ago.  I believe, based on the chips, that they are 4k refresh, 60ns EDO.  I will say that with only one dimm in ram slot a and the twin turbo card in it, it was able to boot up and restart a couple of times.  on the last attempt though it crashed on an error 11 while I was in the system profiler (os 9.2.2), possibly related to the G3 cpu speed.

 

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On further testing, it appears that this particular G3 upgrade does not like memory slot B1.  I'll have to remember that if I ever decide to max out its ram.  I will see if it has any more start up issues in the next few days but so far its working ok right now.  Kind of odd because I actually did try pulling out ram earlier and still had some problems, but maybe that was caused by something else.

 

Now to figure out whats wrong with my 6100 floppy drive eject motor...

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Hmm, this is strange.

 

I know this has been known to happen on some G5s, though that comes from excessive hot-cold cycling from heavy usage.

 

Given that your 9600 has been sitting in storage for ~12 years, it's possible this problem is simply being caused by some dirty or corroded pins in slot B1. Did you try cleaning it? Lightly spraying some contact cleaner, if you have any (or rubbing each pin lightly with a pencil eraser), should do the job.

 

That wouldn't necessarily explain why it works with the 604e CPU, though. Weird!

 

Even though there's no signs of leakage, if the caps are the electrolytic kind, it might be wise to get it recapped, since they've got to be at least 20 years old by now.

 

c

Edited by CC_333

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Have you tried removing the heat sink on the G3 upgrade, cleaning the dried out heat sink goo, and reapplying new heat sink compound?  After 12 years, teh heat sink compound is likely to be largely useless dust.

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You might be having problems with Speculative Access.  Basically, all modern CPUs guess what instructions might come next, execute them, and then keep or discard the results.  This is a problem when the CPU guesses I/O instructions that change the state of something, and G3 upgrades in Old World Macs tend to make these bad guesses.  The symptoms are random stability issues, data corruption, and failure to boot.

 

Fortunately, someone made an extension called ROM Fixer which disables Speculative Access, and I found a copy on the Wayback Machine (also attached to this post).  In my G3 upgraded 9600, this solved all my problems except the occasional failure to boot; the three-finger salute gets it going after one or two tries.  I have the extension installed in both System 7.6.1 and Mac OS 9.2.2, and it's probably compatible with every version of the classic Mac OS a 9600 can boot.

 

http://macos9lives.com/smforum/index.php?topic=2656.msg27281#msg27281

ROM_Fixer.sea.hqx

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Hmm, interesting.

 

Is disabling speculative access the same as disabling speculative execution?

 

c

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Could be a weak power supply too.   I had a similar problem with the G3/1000 upgrade in my S900 based frankentosh, and replacing the ATX power supply made it go away.   Of course, all the handling to replace the power supply could have jiggled something just right too...

 

Also, not  a bad idea to (carefully, delicately) clean and replace the CPU/heat sink grease.  After so many years, it may be dried out.

 

I wish I had bought some of those upgrades when they were clearing them out for $100 each, but it just never seems to be a good time to spend that kind of money in the present.

Edited by trag

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So a bit of an update, I never did figure out why the upgrade liked some ram in some slots but not in others. Seeing as how it works with the 512 megs I have and I don't plan on maxing it, I'm not going to worry too much about it.  As an FYI for things mentioned above, I did not see any signs of contact corrosion, I did use compressed air to blow them out but didn't try any contact cleaner or the like.  I had already disabled speculative access as well as reapplying the heat sink with fresh thermal material, mostly because I had to replace the small fan that came with it when I broke a couple of blades by being... over zealous with compressed air while cleaning out all the gunk that had built up over the years.

 

I am ashamed to say this particular 9600 is in pretty rough physical shape so is even more prone to gathering dust and debris. When I bought it off eBay the seller shipped it in quite a large box with quite not a large amount of shipping material protecting it.  Perhaps a dozen news paper pages waded up?  It arrived to me with almost every plastic tab on every case panel/bezel snapped off, and parts of the frame slightly bent.  At the time I didn't much care since it worked just fine and I thought it looked "cool", but years later I still kick myself for tossing the broken pieces instead of trying to fix them.  Live and learn, and I thank everyone for their help in troubleshooting.

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Oh.  If you have a broken case, is the top end of the CPU card supported by the case?   I've seen old X500/X600 class motherboards that have been in use for a long time in towers, on which the top of the CPU card was not supported develop problematical CPU sockets.   Too many years with the CPU card trying to lean downwards at the far end.

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There is small metal clip that supports the original CPU card just fine, but it doesn't do my upgrade any good since this particular one is a very small board compared to some of the other upgrades I've seen.  It's no wider then the CPU socket itself.  Everything is pretty tight though and there isn't much play in the card.

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