12 Jun
2009
12 Jun
'09
1:54 a.m.
Wow. "I don't read [anything]."
I'm done with this. This is either troll bait or a truly sad psychopathology.
---
Folks, let get on with things. Hey, we just got a restored PDP-8/TC08/TU56 booting OS/8!
After calibrating the TC08, I turned off the system to put all the 'skins' back in
place, fired it up... and it wouldn't boot After checking the obvious things, I
decided to let the system warm up for fifteen minutes or so. Yep, it booted fine.
Something tells me I need to look at the RC components in those one-shots and clock
circuits, and probably replace some realllllllllly old capacitors. -- Ian
________________________________________
From: cctalk-bounces at classiccmp.org [cctalk-bounces at classiccmp.org] On Behalf Of
Kirn Gill [segin2005 at gmail.com]
Sent: Thursday, June 11, 2009 9:18 PM
To: On-Topic and Off-Topic Posts
Subject: Re: the arrogance of youth [was RE: UNIX V7]
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Hash: SHA1
Rich Alderson wrote:
Simply because you don't hear about an OS in
_Linux Journal_ does
not mean that it's dead, or even ailing.
I don't read _Linux Journal_. Or
_BusinessWeek_. Or any magazines.
I occasionally glance at Slashdot if I'm desperate. It's quickly
becoming a reorganizing 'digg' link aggregate.
Otherwise, I just Google for nonsense terms. The news you find that way...
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iEYEARECAAYFAkox1yoACgkQF9H43UytGibF1QCggHyvvhtqRSMJs0TBQ8pftPrR
ReEAnj0b/Xrp1PvkoUdRbRBS6lxPWRvk
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12 Jun
12 Jun
2:37 a.m.
New subject: Move on, nothing to see here (was RE: the arrogance of youth [was RE: UNIX V7])
Ian King wrote:
we just got a restored PDP-8/TC08/TU56 booting OS/8!
Cool!
After calibrating the TC08, I turned off the system
to put all the 'skins' back in place, fired it up... and it wouldn't boot
After checking the obvious things, I decided to let the system warm up for fifteen minutes
or so. Yep, it booted fine.
Something tells me I need to look at the RC components in those one-shots and clock
circuits, and probably replace some realllllllllly old capacitors. -- Ian
I can't imagine that they would have used electrolytic capacitors in
those, and I don't think ceramics are likely to have gone bad unless
they've been subject to extreme mechanical shock. I'm not sure about
other kinds of capacitors, but I'd expect they'd most likely have used
ceramic.
I certainly wouldn't go replacing ceramic capacitors without using some
freeze spray to confirm that it is a temperature problem and identify
the failing component.
Eric
3:30 a.m.
New subject: Move on, nothing to see here (was RE: the arrogance of youth[was RE: UNIX V7])
Eric Smith wrote:
Ian King wrote:
Not sure what type of components DEC was using in these, but on the R side,
carbon-composition resistors tend to drift high with age.
I just pulled out a few-K series flip-chips ca. 1971 and made some measurements
on several dozen 10% carbon comp R. All of them were *above* target, with a
couple of them a little above tolerance (out of spec).
(An early 60's RACAL receiver I was rebuilding recently had over a third of the
resistors above tolerance.)
we just got a restored PDP-8/TC08/TU56 booting
OS/8!
Cool!
After calibrating the TC08, I turned off the
system to put all the 'skins' back in place, fired it up... and it wouldn't
boot After checking the obvious things, I decided to let the system warm up for fifteen
minutes or so. Yep, it booted fine.
Something tells me I need to look at the RC components in those one-shots and clock
circuits, and probably replace some realllllllllly old capacitors. -- Ian
I can't imagine that they would have used electrolytic capacitors in
those, and I don't think ceramics are likely to have gone bad unless
they've been subject to extreme mechanical shock. I'm not sure about
other kinds of capacitors, but I'd expect they'd most likely have used
ceramic.
I certainly wouldn't go replacing ceramic capacitors without using some
freeze spray to confirm that it is a temperature problem and identify
the failing component. 
9:44 a.m.
New subject: Move on, nothing to see here (was RE: the arrogance of youth [was RE: UNIX V7])
----------------------------------------
Date: Thu, 11 Jun 2009 23:37:37 -0700
From: eric at brouhaha.com
To:
Subject: Re: Move on, nothing to see here (was RE: the arrogance of youth [was RE: UNIX
V7])
Ian King wrote:
Hi
The older ceramics are notorious for going short when used
in low current applications. As bypass caps they would self
remove the short because of the current. In low current
applications they just become vary leaky.
Having worked on pinball machines, I've replaced a lot
of these bad caps when used in the switch inputs.
I've also replaced a few when in the services on radio
equipment.
I'm told it is related to metal migration.
I have seen tantilum caps used for RC timing.
Dwight
_________________________________________________________________
Insert movie times and more without leaving Hotmail?.
http://windowslive.com/Tutorial/Hotmail/QuickAdd?ocid=TXT_TAGLM_WL_HM_Tutor…
we just got a restored PDP-8/TC08/TU56 booting
OS/8!
Cool!
After calibrating the TC08, I turned off the
system to put all the 'skins' back in place, fired it up... and it wouldn't
boot After checking the obvious things, I decided to let the system warm up for fifteen
minutes or so. Yep, it booted fine.
Something tells me I need to look at the RC components in those one-shots and clock
circuits, and probably replace some realllllllllly old capacitors. -- Ian
I can't imagine that they would have used electrolytic capacitors in
those, and I don't think ceramics are likely to have gone bad unless
they've been subject to extreme mechanical shock. I'm not sure about
other kinds of capacitors, but I'd expect they'd most likely have used
ceramic.
I certainly wouldn't go replacing ceramic capacitors without using some
freeze spray to confirm that it is a temperature problem and identify
the failing component.
Eric
4:16 p.m.
New subject: old ceramic capacitors (was Re: Move on, nothing to see here (was RE: the arrogance of youth [was RE: UNIX V7]))
I wrote:
I don't think ceramics are likely to have gone bad
unless
they've been subject to extreme mechanical shock.
dwight elvey wrote:
The older ceramics are notorious for going short when
used
in low current applications. As bypass caps they would self
remove the short because of the current. In low current
applications they just become vary leaky.
Having worked on pinball machines, I've replaced a lot
of these bad caps when used in the switch inputs.
I've also replaced a few when in the services on radio
equipment.
I'm told it is related to metal migration.
I stand corrected! I've never observed that problem previously, but now
I know another thing to watch out for when restoring old machines. I'll
have to mention this to the other guys on the PDP-1 team. Maybe this
might be one of the problems with the notoriously unreliable pulse
amplifier modules. On the other hand, they were notoriously unreliable
even when new.
4:46 p.m.
New subject: old ceramic capacitors (was Re: Move on, nothing to see here (wasRE: the arrogance of youth [was RE: UNIX V7]))
Eric Smith wrote:
I wrote:
Just to note, micas can suffer from metal migration as well.
I don't think ceramics are likely to have
gone bad unless
they've been subject to extreme mechanical shock.
dwight elvey wrote:
The older ceramics are notorious for going short
when used
in low current applications. As bypass caps they would self
remove the short because of the current. In low current
applications they just become vary leaky.
Having worked on pinball machines, I've replaced a lot
of these bad caps when used in the switch inputs.
I've also replaced a few when in the services on radio
equipment.
I'm told it is related to metal migration.
I stand corrected! I've never observed that problem previously, but now
I know another thing to watch out for when restoring old machines. I'll
have to mention this to the other guys on the PDP-1 team. Maybe this
might be one of the problems with the notoriously unreliable pulse
amplifier modules. On the other hand, they were notoriously unreliable
even when new. 
13 Jun
13 Jun
7:21 a.m.
New subject: Move on, nothing to see here (was RE: the arrogance of youth [was RE: UNIX V7])
On Thu, 2009-06-11 at 23:37 -0700, Eric Smith wrote:
those, and I don't think ceramics are likely to
have gone bad unless
hahaha haha hahahahaha hahaha hahahahahaha hahaha haha
You've never worked on 1980s TVs and video recorders, have you?
Excuse me, I need to take my pills now. These little brown flat ones...
AARGH!
Gordon
5513
days inactive
5514
days old
6 comments
5 participants
participants (5)
-
dkelvey＠hotmail.com -
eric＠brouhaha.com -
gordonjcp＠gjcp.net -
hilpert＠cs.ubc.ca -
IanK＠vulcan.com