• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

Weird Quadra 700 Bus Error

broccoliwithattitude

Active member
Hello guys (-:

I own a Quadra 700 with the PPC upgrade.
Since I installed the PPC it started acting up, throwing bus errors all the time when the upgrade card is enabled. However, starting with extensions disabled leads to a successful boot.

Lately the HDD also was acting up and ultimately died. So I installed SCSI2SD and it seemed all ok.

No, starting in 68040 is all good but starting in PPC still throws bus error. Also, when I power in PPC mode the “info on this macintosh” screen is all glitched up and the memory bar is out of bounds. In 68040 mode is fine.

Is the RAM going bad? I don’t get it…

thank you!
 

jessenator

Well-known member
I'm no expert on the PPC upgrades, but here's what I'd do first:

I would go ahead and check for dirt/dust, corrosion, or anything else on both PDS connectors. Also, check the PPC card visually for anything that might be a damaged trace, or even faulty board component.

Also, if the Q700's RAM was bad, you'd likely have a lot of errors in 040 mode, including a death chime I imagine. A RAM check test like Apple Personal Diagnostics or MacTest Pro would be able to test it in depth if you further suspect it. I'd also check the DRAM and sockets for the same as the PDS slot: dust, dirt, and whatever else that might be.

But I have to ask: is your PPC card one of the fancier, non-Apple-branded ones with its own DRAM on the card itself? If that's the case, I'd check the DRAM and slots there as well.
 

broccoliwithattitude

Active member
I'm no expert on the PPC upgrades, but here's what I'd do first:

I would go ahead and check for dirt/dust, corrosion, or anything else on both PDS connectors. Also, check the PPC card visually for anything that might be a damaged trace, or even faulty board component.

Also, if the Q700's RAM was bad, you'd likely have a lot of errors in 040 mode, including a death chime I imagine. A RAM check test like Apple Personal Diagnostics or MacTest Pro would be able to test it in depth if you further suspect it. I'd also check the DRAM and sockets for the same as the PDS slot: dust, dirt, and whatever else that might be.

But I have to ask: is your PPC card one of the fancier, non-Apple-branded ones with its own DRAM on the card itself? If that's the case, I'd check the DRAM and slots there as well.
Hey, thank you for your answer (-:

No, it’s not one of the fancy ones. It’s the Apple issued one. A guy gave it to me after i spotted it on his cupboard as he was using it as decoration (in the box).

No sign of corrosion, it’s almost as new. Dusty, that is. Now that I think about RAM, when I first reinstalled the system the installer said i needed at least 8mb of ram. I have 20mb. Then I hit restart and it booted from 68040 and I could install.

Somehow the system has an hard time recognising RAM when booted in PPC mode. However, disabling all extension let it boot. So I don’t really know. Maybe the PPC card is bad, or RAM or there is something in extensions troubling it.

When restated with no extensions seems to work fine, RAM bar glitch aside. So it’s something concerning RAM and PPC. Very strange indeed…
 

Byrd

Well-known member
Hi @broccoliwithattitude,

I'd to a fresh Mac OS install, and while you've got the card out remove the heatsink and reapply thermal paste to the 601 CPU. Contact cleaning spray on the card's connector wouldn't go astray either.
 

broccoliwithattitude

Active member
Hi @broccoliwithattitude,

I'd to a fresh Mac OS install, and while you've got the card out remove the heatsink and reapply thermal paste to the 601 CPU. Contact cleaning spray on the card's connector wouldn't go astray either.
hi, thank you for your answer (-:

I already did a fresh system7 install with no avail. There is probably something wrong with the card, I'll try cleaning it and see how it goes. Worst case scenario I'll have to always disable the extensions when I need to use PPC apps.
 

Daniël

Well-known member
Hi @broccoliwithattitude,

I'd to a fresh Mac OS install, and while you've got the card out remove the heatsink and reapply thermal paste to the 601 CPU. Contact cleaning spray on the card's connector wouldn't go astray either.
Note, be VERY careful when detaching and attaching the heatsink. Those 601 processors with their exposed dies are fragile buggers that can crack and break easily.
 

broccoliwithattitude

Active member
Note, be VERY careful when detaching and attaching the heatsink. Those 601 processors with their exposed dies are fragile buggers that can crack and break easily.
Hey, thank you (-:

I'm scared now. I don't know if I'll pop that card off. If I kill it, who knows if I can find another one.

Besides, confirmed it is a PPC-RAM issue. When started in PPC mode, even with extensions off, it won't open any app cause it detects no ram. I could try maxing the RAM to 68mb and see what happens but it's very strange.

Also, it won't retain the settings and always start in PPC mode. It has no PRAM battery, so maybe that's why. To enter 040mode I have to hit the restart button. That always starts in 040.
 

jessenator

Well-known member
Also, it won't retain the settings and always start in PPC mode. It has no PRAM battery, so maybe that's why. To enter 040mode I have to hit the restart button. That always starts in 040.

Question for the more experienced—I may be way off base—could this be because of 24- vs 32-bit addressing? Without a PRAM battery that's not on by default in certain versions of System 7. Or is that something that doesn't matter when booting into PPC mode? IIRC my Q700 would default into 24-bit addressing…

It's definitely a good idea to have a PRAM battery solution, unless you're just constantly tinkering.

edit: have you had a look at this? https://www.applerepairmanuals.com/the_manuals_are_in_here/Power_Macintosh_Upgra#C5891.pdf
These usually aren't terribly helpful, but you never know :)
 
Last edited:

broccoliwithattitude

Active member
Question for the more experienced—I may be way off base—could this be because of 24- vs 32-bit addressing? Without a PRAM battery that's not on by default in certain versions of System 7. Or is that something that doesn't matter when booting into PPC mode? IIRC my Q700 would default into 24-bit addressing…

It's definitely a good idea to have a PRAM battery solution, unless you're just constantly tinkering.

edit: have you had a look at this? https://www.applerepairmanuals.com/the_manuals_are_in_here/Power_Macintosh_Upgra#C5891.pdf
These usually aren't terribly helpful, but you never know :)
Thank your for the manual. (-: I actually have the original box with the floppies manual etc, and the official apple one is not very helpful either.

However what itches me is that basically they say "add more RAM" as a solution for everything. I'll try doing that then. Made me laugh a bit.

In case of uncertainty, add more RAM.

P.S. mine would always start in 32bit addressing, even on 040.
 

jessenator

Well-known member
not very helpful either
Exactly! There's a funny joke in 65scribe's video on the Quadra 800 where he needs to replace a bogus AppleCD 300i:

hey say "add more RAM" as a solution for everything.
"we said said 'here's the minimum' but you need to add more" :ROFLMAO: yeah, it's a funny thing.

I'm hoping a PowerPC card expert will chime in, because I'm clearly leading you nowhere :)
 

broccoliwithattitude

Active member
Exactly! There's a funny joke in 65scribe's video on the Quadra 800 where he needs to replace a bogus AppleCD 300i:


"we said said 'here's the minimum' but you need to add more" :ROFLMAO: yeah, it's a funny thing.

I'm hoping a PowerPC card expert will chime in, because I'm clearly leading you nowhere :)
I swear their trouble session in pamphlet are always bogus. Literally under almost every trouble:

-Add more RAM (you don't say)
-Switch off PPC Card

Excuse me, my good sir, why then have I got this card for?
They are basically saying put more RAM or pretend the PPC card doesn't exist baby, never existed. wtf ahahah

Oh another issue. It won't retain any setting. I changed the sounds and they always revert to the default. )-:
 
Top