my 7600 did not make a sound at and did not start at all when the
processorcard was not properly seated or when there was some small
shortcircuit, the machine would "feel" that and turn off faster than
the audible click.
a bad pram battery did also produce absolutely NO life . in an older
mac maybe 8160 or so.
k
Date: Thu, 22 Dec 2005 02:45:02 -0500
From: "Greg Shafritz" <[EMAIL PROTECTED]>
I have a stock WGS 9150/120 with 256 MB of RAM installed
that mysteriously stopped working in a way that I have NEVER
seen before!
The machine was operating completely normally (with OS 7.6.1)
and I merely needed to restart after installing some new software.
So I selected "Restart" from the Special menu...
and the screen went blank, and the system went to reboot...
... but absolutely nothing happened after that!!!
(NO startup chime, no image or blank raster on the screen,
no Sad Mac error code or error tones... NOTHING!
It's as if restarting the system KILLED IT!!!!
So far, I have tried the following, all without success:
1. Replaced the PRAM battery with a brand new one
2. Removed all hard drives and tried to boot from known good drive
3. Replaced the internal SCSI cable
4. Removed ALL NuBus cards
5. Took out the PDS terminator from the PDS slot and replaced it
with another known good PDS terminator
6. Tried to "bypass" the internal 120 MHz 601 PPC CPU by inserting
a NewerTech Maxpowr G3 upgrade into the PDS slot
NONE of these steps have worked.
I still get NOTHING when I turn the power on... not even a startup chime.
If you mean that none of the fans spin up and none of the hard
drives spin up, then you have a power problem of some kind. If one
desolders the CPU from the circuit board, the machine will still
spin up the fans and hard drives when you push the power button on
the keyboard (the 6502 in the CUDA chip handles power-on). So if
you're getting nothing, including no fan or drive noise, then the
power supply is the place to look.
Now, could you have a loose power cable? :-)
Oh, hey, this machine has a keyswitch to protect it from operation
by unauthorized folks. Could you have turned that key
inadvertently? Is the keyswitch in the correct position? Is the
cable to the keyswitch connected inside the computer properly. You
may wish to use an ohmmeter or continuity checker to test that the
keyswitch is working properly. It could be broken or dirty. This
is the kind of problem that probably best fits your symptoms.
Have you tried using the power-on button on a different keyboard?
Have you tried using a different keyboard cable? Have your removed
all ADB devices except the keyboard?
I believe, but am not 100% certain that the 8100 and 9100 use teh
same power supply connector and pinout. So, if you have an 8100 MB
around you could test your 9100 power supply. And vice versa with
an 8100 power supply. I'm pretty sure I tested a 9100 MB using an
8100 PS, a while back, but the memory is hazy. Of course you do
this test on the bench. The 8100 components don't go in the 9100
case.
Another possibility is that the power-on circuitry on the 9100 board
may have failed. Have you had any problems where the machine was
difficult to turn on--turns on and turns itself back off? That
would indicate that capacitors in the Power-on circuitry might be
bad. Alternatively, your CUDA chip could be dead. This isn't as
bad as it sounds, as the chip only has 28 pins and can be salvaged
off machines from Quadra 605s to PM7200s. Personally, I'd kill a
7200 before I'd kill a Q605.
If the fans and drives do spin up but the machine fails to chime,
then you could still have a failed power supply (good 12V, failed 5V
and/or 3.3V (3.3V on 9100 PS?)). In most cases where the fans
spin, but the machine does not chime, there is a MB problem. These
range from a loose power supply cable to the MB to a cracked CPU.
Could also be loose RAM or cache. You may wish to pull the cache
and pull and reseat the ROM. However, if the fans aren't spinning,
then this is not your problem.
It would be mighty coincidental if your CPU cracked just as you were
restarting. Is you heat sink properly seated, the Peltier unit
plugged in and the CPU fan in place and operating properly?
Still, I think that the keyswitch is your best/first place to look for issues.
Jeff Walther
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