26 Apr
2004
26 Apr
'04
2:58 a.m.
No signs of life from the PSU but there normally
isn't until powerup and the
LED lights up.
Usually the vent fan will start spinning right away. If the fan doesn't
even jerk, then the PS may not be doing anything. I've used that to track
problems in some macs before (Mac PSs tend to be "short resistant", at
least that is what I've found. If there is a short somewhere, the PS will
power itself back off rather than fry itself... in those cases, the fan
usually jerks as the PS comes on and cycles right back off)
It is starting to sound like the PS is dead.
There are no additional troubleshooting steps listed in the Apple tech
manual for the IIfx (actually, there are no troubleshooting steps at ALL
in that manual).
-chris
<http://www.mythtech.net>
26 Apr
26 Apr
3:35 a.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of chris
Sent: 26 April 2004 15:58
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: Mac IIfx update
Usually the vent fan will start spinning right away. If the
fan doesn't even jerk, then the PS may not be doing anything.
No jerk, but I've already swapped the PSU with one from another Mac II and
got similar results, though I guess it's entirely possible that one's toast
as well. Nothing obviously physically wrong with the PSU though, no bulging
caps etc. Was there a common cause of death for them?
It is starting to sound like the PS is dead.
There are no additional troubleshooting steps listed in the
Apple tech manual for the IIfx (actually, there are no
troubleshooting steps at ALL in that manual).
That's helpful of them :)
Cheers
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
7:44 p.m.
I would take everything out, memory, drives etc., use a known good apple
brand mouse and keyboard and see if some minimum system doesn't get some
kind of response. ADB, SCSI, and memory can all look like this IIRC.
BTW now is when its nice to have a good old Snooper board around. ;)
8:25 p.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of Mike Ford
Sent: 27 April 2004 08:44
To: General Discussion: On-Topic Posts Only
Subject: RE: Mac IIfx update
I would take everything out, memory, drives etc., use a known
good apple brand mouse and keyboard and see if some minimum
system doesn't get some kind of response. ADB, SCSI, and
memory can all look like this IIRC.
I thought the fx required memory to be present to boot? So far my minimal
system has been system ROM/memory/known good kb/rodent but I still don't get
+5V on the ADB cable to the keyboard or anywhere on the motherboard
connector.....it's looking very dead-PSU-ish now.
BTW now is when its nice to have a good old Snooper
board around. ;)
I assume that's a diagnostic board for dead nubus machines?
Cheers
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
27 Apr
27 Apr
5:11 a.m.
I would take
everything out, memory, drives etc., use a known
good apple brand mouse and keyboard and see if some minimum
system doesn't get some kind of response. ADB, SCSI, and
memory can all look like this IIRC.
I thought the fx required memory to be present to boot? So far my minimal
system has been system ROM/memory/known good kb/rodent but I still don't get
+5V on the ADB cable to the keyboard or anywhere on the motherboard
connector.....it's looking very dead-PSU-ish now.
BTW now is when its nice to have a good old
Snooper board around. ;)
I assume that's a diagnostic board for dead nubus machines?
5:30 a.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of Mike Ford
Sent: 27 April 2004 18:12
To: General Discussion: On-Topic Posts Only
Subject: RE: Mac IIfx update
Anyone in the UK with one of these? :)
I assume that's a diagnostic board for dead
nubus machines?
Yeah, Snooper has a nubus card that checks all voltages etc.
with leds. Does the ADB have a fuse?
Apparently it's fed off one of the 2 small upright boards in the PSU....this
afternoon I dismantled and cleaned said PSU for a visual check and there's
no burning or obvious leakage occurred so do I carry on troubleshooting or
get another one from the US for $10+s/h?
Actually, some of the copious glue that's on this PSU has burned and cracked
on what looks like 2 ballast resistors, but I guess they get v.hot so that's
OK.
Heh, about time to try swapping in a known good IIfx
motherboard. ;)
:)
Cheers
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
9:22 a.m.
Yeah, Snooper has a nubus card that checks all
voltages etc. with leds.
I guess a DMM and a nubus pinout would be as useful if not more so. At
least on the PC side, the 'diagnostic cards' tend to just have an LED and
resistor from each power line to ground. So if the line is low, but not
missing (say the +5V line is sitting at 4.2V or something), the LED still
lights.
Does the ADB have a fuse?
Heh, about time to try swapping in a known good IIfx motherboard. ;)
Or actually fixing the problem properly by making some measurements and
finding what's failed rather than replacing random parts until the fault
goes away. As I've said before, this is no way to fix anything, certainly
not a computer!
-tony
9:18 p.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of Tony Duell
Sent: 27 April 2004 22:23
To: cctalk(a)classiccmp.org
Subject: Re: Mac IIfx update
Well, like I posted yesterday I've cleaned and dismantled the PSU and
verified it's not giving out any voltage at all. There's evidence of heat
damage on what looks like ballast resistors next to a relay that must be
triggered by the 5V ADB line to actually powerup the PSU, but I'd guess
those things get hot anyways.
There's a pic at http://www.wowrarelook.co.uk/DSCF6517.JPG. The cracking in
the post-assembly hot glue can be seen lower left of the pic. (I know that
doesn't help you, Tony :) The resistors are marked '5W 100ohm J MICRON 8DT'
and there's evidence of solder 'leakage' on the solder side of the board but
again I guess that's down to operational heat rather than excessive heat?
Cheers
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
Heh, about time to try swapping in a known good
IIfx motherboard. ;)
Or actually fixing the problem properly by making some
measurements and finding what's failed rather than replacing
random parts until the fault goes away. As I've said before,
this is no way to fix anything, certainly not a computer! 
28 Apr
28 Apr
9:33 a.m.
Well, like I posted yesterday I've cleaned and
dismantled the PSU and
verified it's not giving out any voltage at all. There's evidence of heat
damage on what looks like ballast resistors next to a relay that must be
triggered by the 5V ADB line to actually powerup the PSU, but I'd guess
those things get hot anyways.
Yes, there is second 5V for standby for the ADB and batteries in the
IIfx does the rest for power up. Relay closes AC power for the
AC monitor socket and kicks the main SMPS into action.
Turn over and look at solder connections are they good? If not,
resolder them. This is odd because this SMPS in Mac II family
usually uses 2 sided fiberglass PCB not this cheap tan biscuit that
is commonly found in TVs.
again I guess that's down to operational heat
rather than excessive heat?
More like operational heat.
Cheers
--
Adrian/Witchy
Cheers,
Wizard
10:46 p.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of jpero(a)sympatico.ca
Sent: 28 April 2004 22:34
To: cctalk(a)classiccmp.org
Subject: RE: Mac IIfx update
Turn over and look at solder connections are they good? If
not, resolder them. This is odd because this SMPS in Mac II
family usually uses 2 sided fiberglass PCB not this cheap tan
biscuit that is commonly found in TVs.
The PSU in my other II uses the same board.....
I'm going to resolder this afternoon once I've cleared some space on my
bench.
Film at 11 :)
Cheers
w
29 Apr
29 Apr
3:54 a.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of jpero(a)sympatico.ca
Sent: 28 April 2004 22:34
To: cctalk(a)classiccmp.org
Subject: RE: Mac IIfx update
Turn over and look at solder connections are they good? If
not, resolder them. This is odd because this SMPS in Mac II
family usually uses 2 sided fiberglass PCB not this cheap tan
biscuit that is commonly found in TVs.
Well, I've resoldered all dull and 2 cracked connections and I still get no
voltage on the outputs so I'm looking at a failed component somewhere in the
5V circuit......
Curses.
Cheers
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
10:48 a.m.
Well, I've resoldered all dull and 2 cracked
connections and I still get no
voltage on the outputs so I'm looking at a failed component somewhere in the
5V circuit......
Can somebody tell me how this auxilliary 5V supply is produced? Is it a
separate linear PSU, a separate swiching PSU, or the main PSU running at
a much reduced drive (like the standby mode of many TVs over here)?
When I know a little more about the supply I might be able to suggest
what to look for.
-tony
30 Apr
30 Apr
3:25 p.m.
Well, I've resoldered all dull and 2 cracked
connections and I still get no
voltage on the outputs so I'm looking at a failed component somewhere in the
5V circuit......
This is about the point where I would be checking continuity on all the
power bus's etc. with an ohmmeter.
7311
days inactive
7315
days old
12 comments
5 participants
participants (5)
-
ard＠p850ug1.demon.co.uk -
cb＠mythtech.net -
jpero＠sympatico.ca -
mikeford＠socal.rr.com -
witchy＠binarydinosaurs.co.uk