18 Jan
2002
18 Jan
'02
5:06 a.m.
-----Original Message-----
From: Julius Sridhar [mailto:vance@ikickass.org]
How much would you pay for a VAX 7000-650?
As much as I could afford to blow on it at the time. I'd love to have a VAX 7000. :)
Regards,
Chris
Christopher Smith, Perl Developer
Amdocs - Champaign, IL
/usr/bin/perl -e '
print((~"\x95\xc4\xe3"^"Just Another Perl
Hacker.")."\x08!\n");
'
18 Jan
18 Jan
5:29 a.m.
On Fri, 18 Jan 2002, Christopher Smith wrote:
Well, the question's kinda moot, since I've decided not to sell it.
Peace... Sridhar
From: Julius
Sridhar [mailto:vance@ikickass.org]
How much would you pay for a VAX 7000-650?
As much as I could afford to blow on it at the time. I'd love to have a VAX 7000. :)
6:39 a.m.
On Fri, 18 Jan 2002, Julius Sridhar wrote:
Well, the question's kinda moot, since I've decided not to sell it.
Tsk-- Sridhar, you're such a tease
-brian.
On Fri, 18 Jan 2002, Christopher Smith wrote:
> > From: Julius Sridhar [mailto:vance@ikickass.org]
How much would you pay for a VAX 7000-650?
As much as I could afford to blow on it at the time. I'd love to
have a VAX 7000. :) 
9:45 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
Whoo! Able to be online again in short notice because two items
blew out. This stupid little SMD ceramic capacitor
stabbed that transformer!
Was working I turned in for the night before. When I got up,
noticed DSL modem is cold and "dead". Yanked the plug out and
metered it. Nada...and resistance on primary coil is open,
secondary is good. Boooo! This is somewhat odd voltage (16VAC),
grabbed 12AC, snipped it's original plug and took right one from my
junk box and spliced it in.
Huh, modem still sick? Felt heat where it shouldn't be, popped all 4
snaps and looked in, aha, shorted cap easily spotted thing, blackened
on one end and fuse opened in input power section before the full
wave rectifier. :-)
I wondered how this SMD cap die this way, this is first
time I saw insides of DSL Nortel Networks modem. :-) oh, that modem
contains 68HC11 uC.
PCB is decent quality but I'm puzzled at no RF shielding. (!!) The
case is just grey plastic halves, guess that anybody can run
computer guts screaming RF emissions without case. Not smart and
guess what, the manual says place modem about foot away from
monitor. No wonder, no RF tin can.
Cheers,
Wizard and DSL modem bought back from dead. :-D
19 Jan
19 Jan
7:50 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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6:58 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
Ouch! What ever happened to user-replacable fuses to
handle such problems?
Yes *there is* SMD 500mA fuse and zener diode but that is AFTER that
darned ceramic capacitor. That why wall wart died and capacitor
started to cook again starting that stink when I tried to power modem
through that shorted cap.
Many transformers have thermal fuses designed to open
the primary circuit
under such conditions. If you can open up the PSU box, you may find a
replacable (with soldering iron and pliers) thermal fuse on top of the
transformer, or stuck under the tape covering the windings.
How diffcult to find this thermal fuse? This wart is hard to get
voltages w/ 16VAC. Most I see are 9, 12 and nothing of to find. I
had to make do w/ 12VAC for short term.
Don't be tempted to short it out, especially not
on something that runs
unattended like this modem. The next time the capacitor shorts, you might
end up with a fire...
Exactly. I have not seen *ceramic* go bad on low voltage unless
lightning did but this is in middle of winter in southeastern
ontario, no zeus lightning till summer. :-O Only time I saw one like
this was in panasonic printer and that was 12 years ago.
Some plastic cases have a conductive (Nickel-based?)
sheilding coating on
the inside. The HP thermal printer that's currently taking up most of my
bench does. Of course cheaper stuff tries to get away with no shielding :-(
Yes, that's right, nothing of this sort. Basically unpainted
grey plastic shells. Oh, Good Thing, maker forgot to put seal
sticker to bar me from cracking open that modem. >:-D
-tony
Cheers,
Wizard
3:01 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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3:28 p.m.
New subject: about those SCA <=> "SCSI-3" adapters
It turns out htat SCSISTUFF.COM was not where I ordered those things for $6,
folks, it was http://www.CableClub.com, in case anybody was wondering whether
I'd hit my head or something.
That's about $10 less than the comparable item from SCSISTUFF.
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Saturday, January 19, 2002 7:01 PM
Subject: Re: Kinda OT but that what's true HW hacker do in a pinch.
circuit
That depends on the transformer. Sometimes it's an external thermal fuse
on top of the tape over the windings (looks like a small metal cylinder,
or sometimes a ceramic block). Sometimes it's under the very top layer of
tape. Sometimes it's under the windings, but can be pulled out from one
end. Sometimes you'd have to unwind the transformer to get to it :-(
And sometimes the primary is designed to be the thermal fuse. If it
overheats, the insulation melts, you get shorted turns, and it either
melts the wire or blows the current-operated fuse. Apparently the former
(wire that's designed to melt after the insulation has melted) actually
meets most safety approvals, and it's the intended failure mode of most
cheap wall-warts over here. Is it any wonder I can't stand the darn things?
>
>
> > Ouch! What ever happened to user-replacable fuses to handle such
problems?
Yes *there is* SMD 500mA fuse and zener diode but that is AFTER that
darned ceramic capacitor. That why wall wart died and capacitor
Brilliant!. This reminds me of a number of other safety features (and
also self-diagnostic features) that fail to work when a fairly common
problem occurs....
> > Many transformers have thermal fuses designed to open the primary
under such conditions. If you can open up the PSU box,
you may find a
replacable (with soldering iron and pliers) thermal fuse on top of the
transformer, or stuck under the tape covering the windings.
How diffcult to find this thermal fuse? This wart is hard to get voltages w/ 16VAC. Most I see are 9, 12 and
nothing of to find. I
had to make do w/ 12VAC for short term.
I'd probably buy a transformer (15V is common over here, and would be
near enough, I think). Mount it in an earthed metal box with primary and
secondary fuses, and a thermal fuse in series with the primary. Oh, and
add decent mains connectors. It may not be as neat as the original, but
IMHO it's safer and easier to repair. That's what I normally do for
missing/defective wall warts. Or sometimes I do it even if I have the
right wall-wart, if I don't think the latter meets _my_ safety standards.
-tony
4:02 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
So, Tony, is there an orderly an reliable way to get these wall-warts open? I
seem to break about half the ones I want to fix. I've seen quite a few with
those fusible links in series with the windings, but the main problem, aside
circuit
That depends on the transformer. Sometimes it's an external thermal fuse
on top of the tape over the windings (looks like a small metal cylinder,
or sometimes a ceramic block). Sometimes it's under the very top layer of
tape. Sometimes it's under the windings, but can be pulled out from one
end. Sometimes you'd have to unwind the transformer to get to it :-(
And sometimes the primary is designed to be the thermal fuse. If it
overheats, the insulation melts, you get shorted turns, and it either
melts the wire or blows the current-operated fuse. Apparently the former
(wire that's designed to melt after the insulation has melted) actually
meets most safety approvals, and it's the intended failure mode of most
cheap wall-warts over here. Is it any wonder I can't stand the darn things?
from getting the right replacements, is getting the
wall-wart opened and
resealed (often possible with MEK or such) such that it still
looks
presentable.
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Saturday, January 19, 2002 7:01 PM
Subject: Re: Kinda OT but that what's true HW hacker do in a pinch.
>
>
> > Ouch! What ever happened to user-replacable fuses to handle such
problems?
Yes *there is* SMD 500mA fuse and zener diode but that is AFTER that
darned ceramic capacitor. That why wall wart died and capacitor
Brilliant!. This reminds me of a number of other safety features (and
also self-diagnostic features) that fail to work when a fairly common
problem occurs....
> > Many transformers have thermal fuses designed to open the primary
under such conditions. If you can open up the PSU box,
you may find a
replacable (with soldering iron and pliers) thermal fuse on top of the
transformer, or stuck under the tape covering the windings.
How diffcult to find this thermal fuse? This wart is hard to get voltages w/ 16VAC. Most I see are 9, 12 and
nothing of to find. I
had to make do w/ 12VAC for short term.
I'd probably buy a transformer (15V is common over here, and would be
near enough, I think). Mount it in an earthed metal box with primary and
secondary fuses, and a thermal fuse in series with the primary. Oh, and
add decent mains connectors. It may not be as neat as the original, but
IMHO it's safer and easier to repair. That's what I normally do for
missing/defective wall warts. Or sometimes I do it even if I have the
right wall-wart, if I don't think the latter meets _my_ safety standards.
-tony
20 Jan
20 Jan
7:28 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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19 Jan
19 Jan
8:32 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Sun, 20 Jan 2002, Tony Duell wrote:
And sometimes the primary is designed to be the
thermal fuse. If it
overheats, the insulation melts, you get shorted turns, and it either
melts the wire or blows the current-operated fuse. Apparently the
former (wire that's designed to melt after the insulation has melted)
actually meets most safety approvals, and it's the intended failure
mode of most cheap wall-warts over here. Is it any wonder I can't
stand the darn things?
The 9V AC wall-warts that are sold with USRobotics/3Com modems are made
this way. I had one spontaneously fail, and could find no problems with
the modem it had powered. The wall-wart had an open primary, so I
disassembled it. Inside, I found the core's plastic bobbin was melted.
While removing the primary windings, I found damage to the enamel wire
that indicated that the wire had been wound too tightly when the core was
manufactured. It appears that a few layers of the primary winding were
shorted out from the factory. What seems to have happened, is that the
remaining primary windings were over voltage, and eventually the heat that
it produced damaged both the plastic bobbin and the wire's enamel
insulation.
USRobotics/3Com still would not send a replacement unit free of change,
even tho this one was clearly factory defective. They want $15 plus
shipping for these pieces of junk.
I've been considering rewinding this particular transformer, just for
practice (I haven't rebuilt one in awhile). I've not yet decided if it's
worth possibly wasting some enamel wire on. I think I'd want to replace
the plastic bobbin if I do decide to rewind this transformer.
-Toth
20 Jan
20 Jan
7:34 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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2:38 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Sun, 20 Jan 2002, Tothwolf wrote:
On Sun, 20 Jan 2002, Tony Duell wrote:
If you want to rewind it just for nostalgia sake, fine. However, a bit
of rustling around in some of the thrift stores would likely turn up a
wall wart with the proper connector and a 9VAC output. I think I saw
one today when looking for a 6VDC one.
- don
And sometimes the primary is designed to be the
thermal fuse. If it
overheats, the insulation melts, you get shorted turns, and it either
melts the wire or blows the current-operated fuse. Apparently the
former (wire that's designed to melt after the insulation has melted)
actually meets most safety approvals, and it's the intended failure
mode of most cheap wall-warts over here. Is it any wonder I can't
stand the darn things?
The 9V AC wall-warts that are sold with USRobotics/3Com modems are made
this way. I had one spontaneously fail, and could find no problems with
the modem it had powered. The wall-wart had an open primary, so I
disassembled it. Inside, I found the core's plastic bobbin was melted.
While removing the primary windings, I found damage to the enamel wire
that indicated that the wire had been wound too tightly when the core was
manufactured. It appears that a few layers of the primary winding were
shorted out from the factory. What seems to have happened, is that the
remaining primary windings were over voltage, and eventually the heat that
it produced damaged both the plastic bobbin and the wire's enamel
insulation.
USRobotics/3Com still would not send a replacement unit free of change,
even tho this one was clearly factory defective. They want $15 plus
shipping for these pieces of junk.
I've been considering rewinding this particular transformer, just for
practice (I haven't rebuilt one in awhile). I've not yet decided if it's
worth possibly wasting some enamel wire on. I think I'd want to replace
the plastic bobbin if I do decide to rewind this transformer.
-Toth 
5:26 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
If you want to rewind it just for nostalgia sake,
fine. However,...
Oops, I may have missed something.
If you need a single output wart of less than 1A I probably have
a spare and will take off list e-quests.
John A.
9:32 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Sun, 20 Jan 2002, John Allain wrote:
Oops, I may have missed something.
If you need a single output wart of less than 1A I probably have
a spare and will take off list e-quests.
The wall-wart I mentioned is a 9V 1000ma. I'm not worried about finding a
replacement. If someone comes across an original USRobotics one they don't
need, I'd be willing to pay shipping tho.
Speaking of USRobotics power supplies, does anyone have a couple loose
power supplies for the older Courier modems? These are very well made
bricks and have a din output connector on their cable.
-Toth
10:22 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Mon, 21 Jan 2002, Tothwolf wrote:
Speaking of USRobotics power supplies, does anyone have a couple loose
power supplies for the older Courier modems? These are very well made
bricks and have a din output connector on their cable.
Oops, actually thats a mini-din output connector.
-Toth
9:26 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Sun, 20 Jan 2002, Don Maslin wrote:
On Sun, 20 Jan 2002, Tothwolf wrote:
The main reason I might rewind it is to practice coil winding. It has been
a few years since I wound anything with wire that small. I already
calculated the proper wire gauge and number of turns, which I had already
estimated as I took off the old windings. I'd trust my own winding work
over that found in prefab wall-warts too.
I'm still searching for a hand operated coil winding machine. I've only
seen a few, and they were all still in use by other people. If anyone
finds one they don't want, even in non-working or incomplete condition,
let me know. These things are likely considered antiques now.
-Toth
I've been considering rewinding this
particular transformer, just for
practice (I haven't rebuilt one in awhile). I've not yet decided if it's
worth possibly wasting some enamel wire on. I think I'd want to replace
the plastic bobbin if I do decide to rewind this transformer.
If you want to rewind it just for nostalgia sake, fine. However, a bit
of rustling around in some of the thrift stores would likely turn up a
wall wart with the proper connector and a 9VAC output. I think I saw
one today when looking for a 6VDC one.
21 Jan
21 Jan
12:31 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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22 Jan
22 Jan
4:45 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Mon, 21 Jan 2002, Tony Duell wrote:
I probably wouldn't want to practice by winding a
mains winding that's
going to be run unattended. But anyway...
I've wound a number of them in the past, including some rather unusual HV
stuff for custom equipment. I'd certainly double check my work with a
meter, but I'd be ok with it.
David Gingery (I think, maybe Vincent Gingery -- AFAIK
they are father
and son) has written a book called something like 'Build a Universal
Coil Winder'. I've not read it, and I've certainly not tried to build
the device, but if it's anything like his other 'build your own exotic
tools' books, then it'll be a design that will work as described, and
will also be a good starting point for your own mods (hackers never
follow instructions, right :-)).
You might want to see if you can get a copy of this book...
I'll search around and see if I can find it.
The only true hand winder I've found online is this one:
http://www.ee.surrey.ac.uk/Workshop/advice/coils/winder1.html
http://www.ee.surrey.ac.uk/Workshop/advice/coils/about_winder.html
Ideally, thats the type of machine I'd like to find or build.
-Toth
12:16 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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23 Jan
23 Jan
12:50 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Tue, 22 Jan 2002, Tony Duell wrote:
On Tue, 22 Jan 2002, Tothwolf wrote:
True, but unfortunately I don't currently own or have access to such a
meter. I would certainly find one to test a transformer core I wound if I
planned to use it unattended.
-Toth
On Mon, 21 Jan 2002, Tony Duell wrote:
You want to do a high voltage insulation test (aka 'megger' test) at
least. And run it at full voltage to make sure nothing flashes over. I probably wouldn't want to practice by
winding a mains winding that's
going to be run unattended. But anyway...
I've wound a number of them in the past, including some rather unusual HV
stuff for custom equipment. I'd certainly double check my work with a
meter, but I'd be ok with it.
12:56 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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24 Jan
24 Jan
12:01 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
On Wed, 23 Jan 2002, Tony Duell wrote:
What would you suggest I look for in a tester? I've been thinking about
getting one for awhile, but I wasn't sure what to look for? Any particular
brand or functions to look for or even avoid?
-Toth
True, but
unfortunately I don't currently own or have access to such a
I wouldn't apply mains to any transformer I'd not meggered. Heck, I
wouldn't apply mains to _anything_ I'd not meggered, and this applies to
brand new consumer electrics/electronics too.
Second-hand meggers are not hard to find in the UK, and are not that
expensive (I paid \pounds 25.00 for an insulation tester, not Megger
brand, but well built, and with selectable test voltages, etc).
10:20 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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2:23 p.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Thursday, January 24, 2002 04:20 PM
Subject: Re: Kinda OT but that what's true HW hacker do in a pinch.
Well, you want a true meter (actually measures and displays the
resistance) rather than a 'go/no go' tester that just says if something
is safe to use or not.
THe most important thing is probably the test voltage. You want to do the
tests at at least tiwce the normal working voltage of the unit (so at
least 500V in the UK). The better testers have the following :
Selectable test voltages (often 100V, 250V, 500V, 1000V). Very useful.
One thing to watch out for is the insulation class you are testing....
Running a 1000v test on insulation rated for 600v isn't the best thing in
the world for it.
Bob
Second-hand meggers are not hard to find in the UK,
and are not that
expensive (I paid \pounds 25.00 for an insulation tester, not Megger
brand, but well built, and with selectable test voltages, etc).
What would you suggest I look for in a tester? I've been thinking about
20 Jan
20 Jan
7:28 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
Ouch! What ever happened to user-replacable fuses
to handle such problems?
Yes *there is* SMD 500mA fuse and zener diode but that is AFTER that
darned ceramic capacitor. That why wall wart died and capacitor from coil.
Cheers,
Wizard
19 Jan
19 Jan
10:46 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
Quothe Tony Duell, from writings of Sat, Jan 19, 2002 at 06:50:27PM +0000:
Ouch! What ever happened to user-replacable fuses to
handle such problems?
They were apparently found to be more than blatantly incompatible with
the "no user serviceable parts inside" stickers, and hence done away
with. It still surprises me that all recently manufactured electronics
equiment isn't sold with cases that are welded, or super-glued,
closed, or that screwdrivers haven't been outlawed.
Many transformers have thermal fuses designed to open
the primary circuit
under such conditions. If you can open up the PSU box, you may find a
replacable (with soldering iron and pliers) thermal fuse on top of the
transformer, or stuck under the tape covering the windings.
Is that only for transformers sold in the U.K., or in the U.S. as
well, and is this something fairly new? (e.g., within the past 10
years or so?) None of the transformers that I've disassembled have
had these fuses in them, but I've not disassembled any made in recent
years.
Some plastic cases have a conductive (Nickel-based?)
sheilding coating on
the inside. The HP thermal printer that's currently taking up most of my
bench does. Of course cheaper stuff tries to get away with no shielding :-(
Aluminum foil and glue to the rescue? :-)
--
Copyright (C) 2001 R. D. Davis The difference between humans & other animals:
All Rights Reserved an unnatural belief that we're above Nature &
rdd(a)rddavis.org 410-744-4900 her other creatures, using dogma to justify such
http://www.rddavis.org beliefs and to justify much human cruelty.
11:23 a.m.
New subject: Kinda OT but that what's true HW hacker do in a pinch.
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8212
days inactive
8218
days old
27 comments
11 participants
participants (11)
-
allain＠panix.com -
ard＠p850ug1.demon.co.uk -
csmith＠amdocs.com -
donm＠cts.com -
edick＠idcomm.com -
jpero＠sympatico.ca -
rdd＠rddavis.org -
rschaefe＠gcfn.org -
tothwolf＠concentric.net -
vance＠ikickass.org -
vaxzilla＠jarai.org