Problems Troubleshooting a Slot-loading
iMac
From Steve:
Hi Charles,
Thanks for all your (compassionate!) advice to all of us
forgotten low-end Mac users out here!
I just finally crossed over to Macs (again - I used to use
Mac Pluses and SEs at my first job and loved them) and
have been heartbroken to encounter a major system problem within a
couple of days of getting my iMac.
I also have an interesting way that I am trying to solve it.
Care to take a look?
Here's my description of it:
- I have an iMac (summer
2001)
- I bought it secondhand with Tiger already installed; there are
no CDs/DVDs
- Installed two (supposedly) 512 MB DIMMs in it.
- At first one came up as only 256 MB, then when I swapped them,
the total was 1 gig
- But then the screen got all sorts of coloured lines across it
and the computer probably froze up (I didn't wait to see this
before turning it off)
- When I've tried to start the unit with both the new and the old
memory, it has stopped at the grey screen with the turning wheel
and got no further
- I've tried many different types of starts, but nothing
works
- Interestingly, on the single-user start, the command prompt
doesn't come up: I can't type anything
- It also refuses to do a safe start
Other possible areas of interest:
- When I first got the computer I noticed it would lose the time
if it was unplugged, so I assume the battery is flat
- Just before all these problems, at one point I changed the
startup drive to start Mac OS 9 (in order to try a RAM-testing
program). I also (pointlessly I guess), ticked for it to start OS 9
even if it actually started in Tiger. I guess the point of this was
to get it to start OS 9 within Tiger if it actually failed to start
in it.
- I bought the unit secondhand, so I don't have the OS X startup
disc - and can't easily get one
- What I have done, though, is to pull out the Mac's drive and
connect it successfully to my PC via a USB drive case, and am able
to read it through Macdrive (cool, huh?)
I'm willing to buy Tiger again if I have to. There are some
Aussies selling the DVD(s) on eBay. I know I could buy the CDs from
Apple, but that would take ages!
I've also noticed a fairly affordable FireWire disk drive on
eBay locally, but no affordable FireWire DVD-drives. (Will any make
and model work with the Mac, or does it have to be for Mac
especially?)
Any suggestions?
I'm heartbroken and lost!
- Steve
Hi Steve,
Sorry to hear of your troubles.
Did the iMac work okay before you installed the
RAM upgrade?
Bad or substandard RAM could be part of the
problem. My son once fried the motherboard in a Power Mac 9500 by installing bad RAM. In any
case, revert to the RAM it had in it when you got it for the
troubleshooting phase.
You really need some sort of bootable disk in
order to vet out this issue, since it won't boot from the system on
the hard drive. I would recommend getting an OS 9 disk and
getting set up with it first (provided that you don't have a
hardware problem. If it will boot from the OS 9 install CD
(hold down the C key while booting) and mount the hard disk, then
you know your basic hardware is functional. Install Tiger when/if
you get it working with the Classic OS.
You should probably reinitialize the hard drive
and start from scratch. I recommend partitioning the drive and
putting OS 9 and OS X on separate partitions.
My guess is that most any FireWire device that
doesn't require Windows-specific drivers should work with a Mac,
but I can't guarantee it.
Charles
From Steve:
Just found an affordable USB DVD drive . . . could you
boot an iMac G3 2001 from that?
Hi Steve,
No; pre-Intel Macs are not bootable (at least in
practical terms) from USB.
Charles
From Steve:
Hey Charles - thanks for your extremely generous answer! You
actually saved me $70 buying a USB DVD drive unnecessarily!
From Steve
Hi Charles,
Just a quicky! I do have a CD, but it is a set up CD
specifically for an old Power Mac
7600. It appears to have an OS on it, but I figured that
doesn't necessarily mean it will start in an iMac, because they are
different hardware. When I put it in before, it did nothing.
So I was wondering, are there other (startup-type) tests I can
do to rule out the worse-case scenario of the motherboard being
fried?
For example, when I booted while hitting the option key, where
it gives you the choice of boot drive, it does show a pic of a hard
drive with the OS X logo.
I thought: Well if it had enough processing brain to do that,
then perhaps the motherboard is okay? Interestingly though, it
doesn't actually show OS 9. So maybe something is funny with
the file structure or something.
What do you think?
(I really appreciate you taking time to reply by the way - know
that in this hour of need it is particularly appreciated!)
Hi Steve,
It's pretty hard to troubleshoot without a
bootable system. You need either a generic install disk or a System
Restore disk for your particular Mac.
I suspect there is something amiss in the file
structure. The appearance of the startup icon is a hopeful
sign.
Have you tried booting into Single User Mode (hold
down command-S at startup)? If this works, you will be in command
line land, with a black background and a lot of code text.
If you get that far, at the localhost# prompt,
type in fsck -y (make sure to include the space before the dash)
and hit Return. That should initiate a disk check. If that doesn't
work, try fsck -fy, which is supposed to force a disk check.
After the diagnostic routine, it will report
whether it was able to find a problem and repair it. Sometimes it
takes several passes.
Good luck.
Charles
Is My Pismo Really Overheating?
From Tom Gabriel:
Hi Charles,
I've got a strange possible problem with my Pismo G3 500 MHz PowerBook running OS X
10.3.9 & 9.2.2. It's never given me any functional problems
whatsoever, but I occasionally check the CPU temperature by
restarting in 9.2.2 and using Gauge Pro, which
won't work in Classic mode - only 9.2.2 rebooted. In the past, it's
been showing between 51-55° C, but last time it showed a
temperature of 72° C, which for G3s should be frying time! (The
fan hadn't cut in.) It also showed a CPU speed of 509 MHz and a
system bus speed of 105 MHz!
Within 15 seconds or so, reported temperature went down to
64°, and CPU speed to 504 MHz, with bus speed at 102 MHz.
Within a minute, it reported at 54° with CPU and bus speeds at
the customary rates of 499.9 & 99.9 MHz respectively.
I don't know (a) what could be causing this sudden heating
problem, or (b) if Gauge Pro is haywire and not reporting
accurately, which I tend to suspect. I have 768 megs of RAM in it,
the 512 stick labeled as PC100 but reporting in System Profiler as
a PC133, yet I doubt this is doing anything to the CPU.
As I say, functionally it has always been fine, though this
obviously worries me. The outer case is quite warm to the touch
around the CPU & hard drive area, but not hot or uncomfortable
if placed on the lap (I had it on a table with a smooth, hard flat
surface when testing).
Do you or any of your other readers have any ideas on this? I'm
mystified and a bit panicky! Thanks for any help you can give!
God Bless,
Tom Gabriel
Hi Tom,
If your Pismo is really running at 70° or
more, it should feel pretty hot to touch, and the fan should
definitely be cutting in.
My first suggestion would be to download Temperature
Monitor (freeware) and run it in OS X 10.3.9, to get a
"second opinion".
If Temperature Monitor also shows it's
overheating, you may have some logic board component on the way
out, or the fan thermostat could just be malfunctioning.
Charles
From Tom Gabriel:
Hey Charles,
I was installing a big update to the System software which had
the hard drive working pretty hard, and the fan did cut in for
awhile, then out when its job was done, so evidently that works
okay.
I downloaded Temperature Monitor, installed it, and it told me
it couldn't find any temperature sensors in the computer to read!
Back to OS 9, and Gauge Pro told me temperatures in the 60s
again (quickly quieted down to 50s)!
Well, I'm stumped, but it looks like the logic board component
you referred to.
Don't know what else to think at this point.
Thanks for your help!
Tom
Hi Tom,
If it only happens when the processor is under
extraordinary load, perhaps noting to worry about.
Charles
From Tom Gabriel:
Hi Charles,
I'd like to mention that I am very appreciative of how quickly
you get back to me (and, I know, with your other readers) with
feedback on an issue. It's totally professional and the mark of a
conscientious writer.
Anyway, one last thing I did as a check on this whole issue,
which I think points in the direction of the real answer: After
operating the Pismo for 3-4 minutes, I rebooted into 9.2 and looked
at Gauge Pro's reading. It was at 50° C, rapidly going down (10
seconds) to 42°. No Mac I have ever owned has ever gotten that
warm that fast, and if it had, I could feel the warmth in the outer
case, especially a laptop (er, notebook). The case felt completely
cool to the touch at that point.
I think I've got Gauge Pro somehow messing up and reporting
temperatures higher by fifteen-twenty degrees C than are actually
present.
Anyway, as you advise, I'm not going to give it a whole lot of
thought unless and until the Pismo starts acting up. And I'll soon
invest in a hard drive that has a SMART temperature sensor (which
my present original does not) so that I can use Temperature Monitor
in X.
Thanks again for your input, I think we've probably got as close
to the truth as we can!
Good Luck and God Bless,
Tom
Hi Tom,
FWIW, back when my Pismo still had its original
500 MHz G3 processor, it would typically run at 35° to 50°
- usually at the lower end. I haven't found a temperature utility
that can read the temp in the 550 MHz G4 upgrade, but it does run
somewhat hotter with the G4. Daystar's replacement processor heat
sink (copper instead of composite) helped significantly with
keeping the fan silent, even running Tiger. That part would work
with the stock processor as well.
Charles
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