28 Jun
2006
28 Jun
'06
1:26 a.m.
A quick question about the Mac G3, if you'll forgive it being not yet
on-topic. Feel free to reply off-list to avoid rampant topic drift...
Does anyone here know about the internals of the G3 line? I have a
motherboard in front of me that I'm attempting to see if it will work.
It came from a machine that had already been stripped, so there's no
guarantee the hardware is functional. With the Apple Reset/NMI board
installed, and RAM, and the Apple-enhanced ATI Rage 128 video card,
I've attempted to see if it works by plugging in a PC ATX power supply
and pressing the "power on" button on the motherboard and on the
Reset/NMI board. I get a brief green flash from several LEDs, but the
PSU doesn't kick on the fan, and the machine does not appear to be
starting.
Do I need an Apple ATX supply to test this? Could this be a battery
problem? (the battery was completely dead and I have no handy
replacement, so the battery compartment is empty)
Do I need to have a keyboard and mouse plugged in to get a response?
Thanks for any tips.
-ethan
28 Jun
28 Jun
4:39 a.m.
Ethan Dicks wrote:
A quick question about the Mac G3, if you'll
forgive it being not yet
on-topic. Feel free to reply off-list to avoid rampant topic drift...
Does anyone here know about the internals of the G3 line? I have a
motherboard in front of me that I'm attempting to see if it will work.
It came from a machine that had already been stripped, so there's no
guarantee the hardware is functional. With the Apple Reset/NMI board
installed, and RAM, and the Apple-enhanced ATI Rage 128 video card,
I've attempted to see if it works by plugging in a PC ATX power supply
and pressing the "power on" button on the motherboard and on the
Reset/NMI board. I get a brief green flash from several LEDs, but the
PSU doesn't kick on the fan, and the machine does not appear to be
starting.
Do I need an Apple ATX supply to test this? Could this be a battery
problem? (the battery was completely dead and I have no handy
replacement, so the battery compartment is empty)
Do I need to have a keyboard and mouse plugged in to get a response?
Ethan,
There are a couple of different G3 system boards with very different
PSU inputs. As far as I know, neither is PC ATX compatible.
www.xlr8yourmac.com has some pages that detail converting an
off-the-shelf ATX PSU for use on a "beige" G3. IIRC, that one requires
a simple inverter board.
The Blue & White G3 I haven't seen plans for, but I'd bet its PSU is
closer to PC-ish.
Doc
9:59 p.m.
On 6/28/06, Doc Shipley <doc at mdrconsult.com> wrote:
Ethan Dicks wrote:
Not surprising.
Does anyone here know about the internals of the
G3 line?
There are a couple of different G3 system boards with very different
PSU inputs. As far as I know, neither is PC ATX compatible. www.xlr8yourmac.com has some pages that detail
converting an
off-the-shelf ATX PSU for use on a "beige" G3...
That's just the sort of tip I was looking for. Thanks!
-ethan
10 Jul
10 Jul
9:47 p.m.
On 6/28/06, Doc Shipley <doc at mdrconsult.com> wrote:
Ethan Dicks wrote:
To close this topic out, I did get it all working. It's a "Blue &
White" G3, 350Mhz, 384MB of RAM, Firewire, ATI Rage 128 video, now
running OS X (10.3). I have no battery, so it won't remember the time
when I power it off, but that's an easy problem to fix once planes
start flying. As for the PSU, I'm using a bog-standard ATX supply
with one modification - I've pulled the -5VDC pin because on this
motherboard, Apple grounded the pin normally used for -5V. That's why
it was pulsing before - the crowbar circuit was preventing the PSU
Does anyone here know about the internals of the
G3 line? I have a
motherboard in front of me that I'm attempting to see if it will work.
There are a couple of different G3 system boards with very different
PSU inputs. As far as I know, neither is PC ATX compatible.
www.xlr8yourmac.com has some pages that detail converting an
off-the-shelf ATX PSU for use on a "beige" G3.
The Blue & White G3 I haven't seen plans for, but I'd bet its PSU is
closer to PC-ish. from frying itself when its -5V line was shorted to
ground at the
motherboard.
I found a page, thanks to the pointers here, about how to mount this
in an ATX case - the only real hitch is that the location of the PSU
connector is too far away from the top of the case for a standard PSU
cable to reach; it will require an extender. Two minor mechanical
issues are the location of the mounting holes and the custom I/O
backplate, but those are trivial to work around.
Thanks again for all the advice.
-ethan
28 Jun
28 Jun
11:19 a.m.
I saw this on a G4 once. I think it was something to do with the monitor
circuit (i.e. no monitor was connected that the card recognized)
I don't know if a standard ATX PSU will work. The G4 I worked on a few
weeks ago seemed to have a standard power supply, but with a seprate pair of
wires for a fan that was connected.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Ethan Dicks
Sent: Wednesday, June 28, 2006 3:27 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Macintosh question (G3, 7 years old, so OT)
A quick question about the Mac G3, if you'll forgive it being
not yet on-topic. Feel free to reply off-list to avoid
rampant topic drift...
Does anyone here know about the internals of the G3 line? I
have a motherboard in front of me that I'm attempting to see
if it will work.
It came from a machine that had already been stripped, so
there's no guarantee the hardware is functional. With the
Apple Reset/NMI board installed, and RAM, and the
Apple-enhanced ATI Rage 128 video card, I've attempted to see
if it works by plugging in a PC ATX power supply and pressing
the "power on" button on the motherboard and on the Reset/NMI
board. I get a brief green flash from several LEDs, but the
PSU doesn't kick on the fan, and the machine does not appear
to be starting.
Do I need an Apple ATX supply to test this? Could this be a
battery problem? (the battery was completely dead and I have
no handy replacement, so the battery compartment is empty) Do
I need to have a keyboard and mouse plugged in to get a response?
Thanks for any tips.
-ethan
11:42 a.m.
Julian Wolfe wrote:
I saw this on a G4 once. I think it was something to
do with the monitor
circuit (i.e. no monitor was connected that the card recognized)
I don't know if a standard ATX PSU will work. The G4 I worked on a few
weeks ago seemed to have a standard power supply, but with a seprate pair of
wires for a fan that was connected.
G4 "Sawtooth" - 350-450MHz, 100Mb ethernet, AGP video - can use a
standard ATX PSU with a simple -wire-wire modification. The other G4
PSUs *look*, standard, but they definitely aren't. The Digital Audio
model requires a 28V supply line....
I don't recall whether a G3 will boot with a dead battery or not, but
I'm fairly sure it won't boot with no battery.
Doc
12:52 p.m.
On 28/6/06 09:26, "Ethan Dicks" <ethan.dicks at gmail.com> wrote:
Do I need an Apple ATX supply to test this? Could
this be a battery
problem? (the battery was completely dead and I have no handy
replacement, so the battery compartment is empty)
Do I need to have a keyboard and mouse plugged in to get a response?
Doc S. has already mentioned the PSU problem, ie you need an Apple one, also
you need a battery fitted otherwise you'll get nothing even with a good PSU.
Macs won't power up without a PRAM battery.....
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
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