14 Feb
2006
14 Feb
'06
7:18 p.m.
Maybe it's the Scrooge in me, but I've got a couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
Cheers,
Chuck
14 Feb
14 Feb
7:36 p.m.
Chuck Guzis wrote:
Maybe it's the Scrooge in me, but I've got a
couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
If it's a variable-speed Dremel and a real saw, as opposed to a
carborundum wheel, that works. Otherwise cutting plastic is just a mess.
I like a regular fine-tooth scroll saw better.
Doc
15 Feb
15 Feb
2:07 a.m.
Maybe it's the Scrooge in me, but I've got a couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
Cheers,
Chuck
10:32 a.m.
Chuck,
You may not believe it but the best method that I've found to get into
wallwarts is to lay them on a hard surface and smack them with a hammer!
It's sort of like cracking open walnuts. If you hit it on a seam you can
usually pop the seam apart. One of the advantges of doing it this way is
that there's no gap to fill such as there would be if you cut it open. It
takes a bit of practice to learn how how to hit them but once you learn you
can pop the shell apart without damaging anything inside.
If you don't trust yourself to break one open then the next best thing
is one of the THIN saws made by Exacto. They're about 6 inches long and fit
in the large Exacto handle. The nice thing about them is that they have
FINE teeth (just right for cutting thin plastic) and the blade is very thin
so there's little gap left to fill when you glue the case back together.
The saw blade is about 1 1/4" deep and has a backbone on it to keep it
stiff. You should be able to find one in any good hobby shop.
Joe
At 11:07 PM 2/14/06 -0800, you wrote:
Maybe it's the Scrooge in me, but I've got a
couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
Cheers,
Chuck
4:07 p.m.
If you don't trust yourself to break one open
then the next best thing
is one of the THIN saws made by Exacto. They're about 6 inches long and fit
in the large Exacto handle. The nice thing about them is that they have
FINE teeth (just right for cutting thin plastic) and the blade is very thin
so there's little gap left to fill when you glue the case back together.
The saw blade is about 1 1/4" deep and has a backbone on it to keep it
stiff. You should be able to find one in any good hobby shop.
When I have needed to cut open a wallwart nicely, I do it on a table
saw. This way I can control the depth of the cut, as well as having a nice
even seam. The only problem (and not much of one, really) is the gap that
might result from the wider width blades.
William Donzelli
aw288 at osfn.org
8 p.m.
When I have needed to cut open a wallwart nicely, I do
it on a table
saw. This way I can control the depth of the cut, as well as having a nice
even seam. The only problem (and not much of one, really) is the gap that
might result from the wider width blades.
Waht about using a slitting saw in a milling machine (or lathe with
vertical slide)? I've seen those down to a few thou' cut width, and you'd
have excellent control off the depth of cut.
-tony
8:16 p.m.
On 2/15/2006 at 3:32 PM Joe R. wrote:
You may not believe it but the best method that
I've found to get into
wallwarts is to lay them on a hard surface and smack them with a hammer!
It's sort of like cracking open walnuts. If you hit it on a seam you can
usually pop the seam apart. One of the advantges of doing it this way is
that there's no gap to fill such as there would be if you cut it open. It
takes a bit of practice to learn how how to hit them but once you learn
you
can pop the shell apart without damaging anything
inside.
Well, I've got a bunch of nice soft-faced hammers, from a 10 oz. rubber
mallet to a rawhide hammer. I started with a NEC 18v 1800ma. cube with a
blown fuse. I whacked that thing until the experience was no longer
cathartic and my arm was tired--nothing. I then grabbed my jeweler's frame
saw and ran the very thin blade down the groove a bit (using a couple of
drops of oil to prevent binding). I didn't cut all the way through; maybe
only the first 1/64 of an inch to weaken the joint a bit. A few more
healthy whacks with a mallet and the thing opened right up, without
damaging a thing!
I wish I'd hung onto the plastic-faced shot-filled flooring hammer I once
owned--it was probably about 20 oz. and you could land some serious blows
with it.
Next up is an early 80's Racal Vadic modem PSU. Not really a wall wart in
the sense that it actually has a line cord; but the caps in it have dried
out and the regulated +/-12, +5 supplies make this one worth salvaging, as
the internal caps have dried out.
Actually, most DC wall warts are doomed if they get warm enough during
operation. Darned things just cook the juices out of the caps.
Thanks all,
Chuck
3:40 p.m.
I've used rubber mallets with much success opening those up. It's a
crapshoot though. Seems to work on Atari power supplies at least.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Chuck Guzis
Sent: Wednesday, February 15, 2006 1:08 AM
To: cctalk at classiccmp.org
Subject: Repairing wall warts
Maybe it's the Scrooge in me, but I've got a couple of wall
warts (power
supplies) that either have open fuses or dried up caps in
them. They're either multi-voltage or have unusual enough
ratings (e.g. 18 vdc @ 1500 ma) that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case
such that it can be reclosed? I was thinking about using a
saw blade on a Dremel to separate the case halves.
Cheers,
Chuck
4:04 p.m.
On Tuesday 14 February 2006 07:18 pm, Chuck Guzis wrote:
Maybe it's the Scrooge in me, but I've got a
couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
Not "sure fire", but the first thing I'd try is a swab soaked in acetone
(nail polish remover :-) along the seam...
I've had some luck with that, anyhow.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
4:14 p.m.
Roy J. Tellason wrote:
On Tuesday 14 February 2006 07:18 pm, Chuck Guzis
wrote:
I've tried that too. I think the hammer trick works better.
Peace... Sridhar
Maybe it's the Scrooge in me, but I've got
a couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
either multi-voltage or have unusual enough ratings (e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
Not "sure fire", but the first thing I'd try is a swab soaked in acetone
(nail polish remover :-) along the seam...
I've had some luck with that, anyhow.
7:27 p.m.
Maybe it's the Scrooge in me, but I've got a couple of wall warts (power
supplies) that either have open fuses or dried up caps in them. They're
Very few wall-wears (at least the ones sold over here) contain fuses any
more. The transformer is designed to burn out in a safe way if
overloaded, or so I am told -- personal experience suggests it does not
do so before the case has started to melt and smoke is coming out!
either multi-voltage or have unusual enough ratings
(e.g. 18 vdc @ 1500 ma)
that I'm reluctant to scrap them.
Does anyone have a sure-fire method for getting into the case such that it
can be reclosed? I was thinking about using a saw blade on a Dremel to
separate the case halves.
The method I normally use is to put a thin piece of metal in the crack
between the case halves and tap it with a hammer. The idea is to shock
the glued joint between the 2 parts. Work round and round the case, in
the end it'll start to separate. You will probably slightly damage one
case half, but nothing serious,
When youv've done the repair, put the parts back together and run a fine
brush dipped in dichloromethane (methylene chloride) round the crack.
That should disolve the plastic and weld the case back together.
Another method of opening them I've heard of, but don't have the courage
to try is to swing the wall wart by the cables against a hard surface
repeatedly until it pops apart....
-tony
8:27 p.m.
On 2/16/2006 at 12:27 AM ard at p850ug1.demon.co.uk wrote:
Very few wall-wears (at least the ones sold over here)
contain fuses any
more. The transformer is designed to burn out in a safe way if
overloaded, or so I am told -- personal experience suggests it does not
do so before the case has started to melt and smoke is coming out!
That's pretty surprising to me, considering that most UK appliances seem to
have a fuse in the mains plug (almost every one I've seen has been 13A, yet
I KNOW other values are sold). Over here, consumer electronics are usually
fused, but appliances are not, depending on the 15 or 20A distribution
panel breaker to trip.
The NEC wart that I just opened has a microfuse in the DC output. Somehow,
I'd expected to see a fuse in the transformer primary. It seems to me that
the fuse as is may protect the attached equipment, but if the transformer
developed a short in the windings, the thing would turn to slag before
opening the circuit.
Cheers,
Chuck
11:45 p.m.
On 2/15/2006 at 5:27 PM Chuck Guzis wrote:
Well, I applied the "smack it and crack it" approach to the Racal-Vadic
supply. It opened, but the break wasn't very clean, mostly because there
isn't a "groove" where the top meets the bottom part of the case. So it
breaks along the weakest line--in this case, the part of the top case just
above the overlap from the bottom part of the case. Somewhat irregular
line, too.
No matter--it can be stuck back together and if I have to repeat this
operation on another wart, I'll remember to score a groove in the case if
it doesn't have one.
Cheers,
Chuck
16 Feb
16 Feb
1:56 p.m.
On 2/16/2006 at 12:27 AM ard at p850ug1.demon.co.uk wrote:
Yes, the standard mains plug over here is rated at 13A, and contains a
cartridge fuse (nromally, 3A, 5A, or 13A). Obviously PSUs with a mains
cable are fitted with such a plug which contains a fuse (even moulded-on
mains plugs [1] have a fuseholder and fuse)
[1] %deity I hate those things. I've had all sorts of problems with them,
Very few wall-wears (at least the ones sold over
here) contain fuses any
more. The transformer is designed to burn out in a safe way if
overloaded, or so I am told -- personal experience suggests it does not
do so before the case has started to melt and smoke is coming out!
That's pretty surprising to me, considering that most UK appliances seem to
have a fuse in the mains plug (almost every one I've seen has been 13A, yet from live/neutral reversed, to no strain relief on the
cable... I cut
them off and put a rewireable plug on the cable.
But wall warts seem never to contain fuses, relying instead on the
transformer burning out in a safe way. Since the fuse in the fusebox is
generally rated at 30A, I am not very happy about this.
I never use wall warts for homebrew projects. I build my own PSU, with
fuses all over the place. OK, I can't stick an approval label on it, but
I am darn sure it's safer.
-tony
8:40 p.m.
On 2/16/2006 at 6:56 PM ard at p850ug1.demon.co.uk wrote:
Yes, the standard mains plug over here is rated at 13A,
and contains a
cartridge fuse (nromally, 3A, 5A, or 13A). Obviously PSUs with a mains
cable are fitted with such a plug which contains a fuse (even moulded-on
mains plugs [1] have a fuseholder and fuse)
Are there any appliances in the UK, save for heaters, that draw 13A? From
my viewpoint in the US, with 120v mains outlets, appliances are rated at
less than 15A. 13A at 220v seems to me to be a huge amount of power. To
be sure, we have some 240v appliances, but they're mostly stationary items,
like ranges (cookers) and clothes dryers and have special (usually a large
crowfoot) receptacles connected to a single distribution panel circuit.
Cheers,
Chuck
17 Feb
17 Feb
8:35 a.m.
Chuck Guzis wrote:
On 2/16/2006 at 6:56 PM ard at p850ug1.demon.co.uk
wrote:
(Looks around)
Single phase welders, plasma cutters, some water boilers, some washing
machines and tumble driers...
Yes, the standard mains plug over here is rated
at 13A, and contains a
cartridge fuse (nromally, 3A, 5A, or 13A). Obviously PSUs with a mains
cable are fitted with such a plug which contains a fuse (even moulded-on
mains plugs [1] have a fuseholder and fuse)
Are there any appliances in the UK, save for heaters, that draw 13A? From my viewpoint in the US, with 120v mains outlets,
appliances are rated at
less than 15A. 13A at 220v seems to me to be a huge amount of power. To
be sure, we have some 240v appliances, but they're mostly stationary items,
like ranges (cookers) and clothes dryers and have special (usually a large
crowfoot) receptacles connected to a single distribution panel circuit.
Electric cookers tend to be wired to a special 30A circuit, and are
permanently installed. Same for immersion heaters and certain panel
heaters, but they're not really considered to be appliances in the same
way (you wouldn't remove it when you move house). Everything else just
plugs in.
Gordon.
5:44 p.m.
On 2/16/2006 at 6:56 PM ard at p850ug1.demon.co.uk wrote:
A medium-sized PDP11 system :-)
More seriously, the main high-power appliances are all based on heating
elements. 3kW portable electric heaters are common (both radiant elements
and fan-assisted ones). Electric kettles tend to be about 2.5kW (so
around 10A)
Yes, the standard mains plug over here is rated at
13A, and contains a
cartridge fuse (nromally, 3A, 5A, or 13A). Obviously PSUs with a mains
cable are fitted with such a plug which contains a fuse (even moulded-on
mains plugs [1] have a fuseholder and fuse)
Are there any appliances in the UK, save for heaters, that draw 13A? From my viewpoint in the US, with 120v mains outlets,
appliances are rated at
less than 15A. 13A at 220v seems to me to be a huge amount of power. To
What's a typical rating for an electric kettle?
be sure, we have some 240v appliances, but they're
mostly stationary items,
like ranges (cookers) and clothes dryers and have special (usually a large
crowfoot) receptacles connected to a single distribution panel circuit.
Tumble driers (and washing machines, dishwashers, which have internal
water heating elements) are just plugged into a normal 13A socket over
here (and they may well aproach the 13A maximum). Most electric cookers
are permanently wired in to a speical circuit, fused at 30A, but there
are small tabletop cookers that just plug into the 13A socket (and again
may well draw close to that current when in operation). Water heaters and
shower heaters are also permanently wired in on special circuits, the
latter might well be fused at 45A (yes, 9kW shower heaters do exist).
Machine tools, etc are generally connected by a different set of
connectors. I know them as 'BS4343', they have a CEN number that I can't
remember. They are colour-coded as to voltage, come in 3, 4, 5 pole
versions (for 3 phase applications), and come in various ratings up to
125A. These connectors do not contain fuses.
Industrial portable power tools are 110V over here, operated from an
isolating transformer with the secondary centre-tapped to ground. The
idea being that if you accidentally touch a single wire, or the
insulation of the tool breaks down, the maximum voltage you will get
across you is 55V which is unlikely to be fatal. The typical transformer
used for these tools is rated at 3kW (OK, strictly 3kVA). I know my
father has an angle grinder which draws over 20A at 110V....
-tony
7:07 p.m.
On 2/17/2006 at 10:44 PM ard at p850ug1.demon.co.uk wrote:
What's a typical rating for an electric kettle?
1200-1500 watts would be typical. So that translates (at 120v) to 10A -
13A). Electric broilers are rated about the same. My vacuum cleaner
(Eureka, not Hoover) claims to have a "powerful 12A motor".
Industrial portable power tools are 110V over here,
operated from an
isolating transformer with the secondary centre-tapped to ground. The
idea being that if you accidentally touch a single wire, or the
insulation of the tool breaks down, the maximum voltage you will get
across you is 55V which is unlikely to be fatal. The typical transformer
used for these tools is rated at 3kW (OK, strictly 3kVA). I know my
father has an angle grinder which draws over 20A at 110V....
I assume that you're familiar with the 120v NEMA 2 wire (ungrounded) and
3-wire (grounded) 15A receptacles.
Much beyond that, it's a free-for-all affair, even under NEMA code.
Rather than enumerate them all here, I'll simply direct you to:
http://www.et-sales.com/Receptacles.htm
When I worked in a steel mill as a summer job during my time at the
university, the distribution there was even more bewildering: 25 Hz (110,
220 single and 440 3-phase); 60 Hz (120V, 240V single-phase, 208V, 440V
3-phase), DC (250V and 660V). I don't recall what the large machinery
(rolling mills, etc.) used, but I'm certain it was different from the stuff
available at the wild array of receptacles. I learned early on that a 110V
25Hz motor would run just fine on 240V 60Hz current. Mercury-vapor
lighting run on 25Hz would send one into an epileptic fit, while
incandescent lighting on 250v was wonderfully bright and steady.
Cheers,
Chuck
18 Feb
18 Feb
1:40 p.m.
On 2/17/2006 at 10:44 PM ard at p850ug1.demon.co.uk wrote:
So same currnet (and thus half the power) of ours.
What's a typical rating for an electric
kettle?
1200-1500 watts would be typical. So that translates (at 120v) to 10A -
13A). Electric broilers are rated about the same. My vacuum cleaner (Eureka, not Hoover) claims to have a "powerful
12A motor".
As if the input current tells you _anything_....
I assume that you're familiar with the 120v NEMA 2
wire (ungrounded) and
3-wire (grounded) 15A receptacles.
I think so. I know the 115V 15A one with the 2 'vertical' blades for live
and neutral (and a U-shaped earth sometimes), the 20A (?) version with
one blade vertical, the other horizontal, and the 230V version with 2
horixontal blades. Oh, and I've seen various twist-and-lock ones
described in DEC manuals.
The 230V 15A connector is common on BEC hardawre over here (unlike
Tektronix, who ued the 115V version no matter what voltage the instrument
was going to be used on). But getting that connector is very difficult,
I've been quoted \pounds 25.00 (about $40) for a single plug. Surely they
are a lot cheaper in the States.
-tony
2:33 p.m.
On 2/18/2006 at 6:40 PM ard at p850ug1.demon.co.uk wrote:
The 230V 15A connector is common on BEC hardawre over
here (unlike
Tektronix, who ued the 115V version no matter what voltage the instrument
was going to be used on). But getting that connector is very difficult,
I've been quoted \pounds 25.00 (about $40) for a single plug. Surely they
are a lot cheaper in the States.
They are--probably around $5 in single-unit quantities. I use one on my
automatic dishwasher.
It's the hospital-grade receptacles and plugs that are dear here. Aside
from an additional endorsement and a different color, I
don't know if they
differ much from the ordinary consumer grade stuff.
Cheers,
Chuck
16 Feb
16 Feb
4:11 p.m.
----- Original Message -----
From: "Chuck Guzis" <cclist at sydex.com>
To: <cctalk at classiccmp.org>
Sent: Thursday, February 16, 2006 1:27 AM
Subject: Re: Repairing wall warts
On 2/16/2006 at 12:27 AM ard at p850ug1.demon.co.uk
wrote:
to
Very few wall-wears (at least the ones sold over
here) contain fuses any
more. The transformer is designed to burn out in a safe way if
overloaded, or so I am told -- personal experience suggests it does not
do so before the case has started to melt and smoke is coming out!
That's pretty surprising to me, considering that most UK appliances seem have a fuse in the mains plug (almost every one
I've seen has been 13A,
yet
I KNOW other values are sold). Over here, consumer
electronics are
usually
fused, but appliances are not, depending on the 15 or
20A distribution
panel breaker to trip.
The NEC wart that I just opened has a microfuse in the DC output.
Somehow,
I'd expected to see a fuse in the transformer
primary. It seems to me
that
the fuse as is may protect the attached equipment, but
if the transformer
developed a short in the windings, the thing would turn to slag before
opening the circuit.
Cheers,
Chuck
A lot of the ones I've seen recently have a thermal fuse on top of the
primary winding.
Geoff.
6805
days inactive
6808
days old
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