10 Sep
2014
10 Sep
'14
6:02 p.m.
Well, they do say that the device is there to protect the fuse...
http://www.classiccmp.org/acornia/tmp/fuse.jpg
Found in the chassis of an old 'scope. There's actually originally no
provision for a fuse in the 'scope itself - just a circuit breaker - but
quite why someone would take the trouble to cut a wire and then solder both
ends of the same fuse to it, I have no idea.
cheers
Jules
10 Sep
10 Sep
6:17 p.m.
On Sep 10, 2014, at 18:02 , Jules Richardson <jules.richardson99 at gmail.com>
wrote:
I think that tops the wire nuts that I found in my Kaypro II, where a previous owner
spliced some speaker cable into the video signal to relocate a contrast control.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
6:25 p.m.
Has anyone ever put a wire nut in a spectrum analyzer to see what the frequency response
is like?
Ian
Sent from my iPhone
On Sep 10, 2014, at 6:17 PM, Mark J. Blair <nf6x at
nf6x.net> wrote:
On Sep 10, 2014, at 18:02 , Jules Richardson
<jules.richardson99 at gmail.com> wrote:
http://www.classiccmp.org/acornia/tmp/fuse.jpg
I think that tops the wire nuts that I found in my Kaypro II, where a previous owner
spliced some speaker cable into the video signal to relocate a contrast control.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
---
Filter service subscribers can train this email as spam or not-spam here:
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6:57 p.m.
Inquiring minds want to know the make and model of the 'scope.
Zane
On Sep 10, 2014, at 6:02 PM, Jules Richardson <jules.richardson99 at gmail.com>
wrote:
Well, they do say that the device is there to protect the fuse...
http://www.classiccmp.org/acornia/tmp/fuse.jpg
Found in the chassis of an old 'scope. There's actually originally no provision
for a fuse in the 'scope itself - just a circuit breaker - but quite why someone would
take the trouble to cut a wire and then solder both ends of the same fuse to it, I have no
idea.
cheers
Jules
7:51 p.m.
On 09/10/2014 08:57 PM, Zane Healy wrote:
Inquiring minds want to know the make and model of the
'scope.
It's actually an automotive 'scope, rather than a lab 'scope - a Sun SS-90.
Late '60s, I think. I picked this one up for parts, but visually it's in
good shape inside (owner said they thought the CRT neck was smashed) so I
might throw some capacitors at it and see what happens - although I got a
King 'scope at the same time, and there's another Sun and a Marquette plus
spare boards and leads on the way, so I don't know which I'll end up
actually using.
cheers
Jules
9:40 p.m.
On 9/10/2014 6:02 PM, Jules Richardson wrote:
protect the fuse...
I hope everyone here knows
that this almost certainly will open the fuse
with such heavy soldering. Buss made fuses with tails on them that
would allow you to direct solder them into a circuit.
This is of course a joke, but the heavy handed soldering job makes me
wonder if the fuse ever did anything at all. The manufacturer would
have been at fault to have put it in in the first place with direct
solder in the yellow wires. I am thinking of a late night scenario in
this case with one of those nifty Weller 500 watt guns that could be
used with copper water pipe and delicate electronics, and someone with
no idea where fuses came from.
Just legislate the problem out of existence by this sort of mess.
Surprised there was no copper penny used as well.
Jim
11 Sep
11 Sep
5:20 a.m.
On 09/10/2014 11:40 PM, jwsmobile wrote:
On 9/10/2014 6:02 PM, Jules Richardson wrote:
It's not original - or at least there's no fuse in the schematics for the
AC input path (which is what the yellow wire is part of). I don't think a
manufacturer would leave a fuse just flapping about in the chassis like
that, either (although having said that there's a 120VAC distribution panel
on the outside of the case at the back with no indication that it ever had
any kind of cover)
As mentioned in another post, this is an automotive 'scope; what I like to
imagine happened is that some apprentice, perhaps in the early '80s,
complained about having to use such an old device which didn't even have a
fuse, and so their boss did this as a joke, showed it to them, and then
told them to just get on with their job (possibly with a good slap on the
side of the head) :-)
cheers
Jules
protect the fuse...
I hope everyone here
knows that this almost certainly will open the fuse
with such heavy soldering. Buss made fuses with tails on them that would
allow you to direct solder them into a circuit.
This is of course a joke, but the heavy handed soldering job makes me
wonder if the fuse ever did anything at all. The manufacturer would have
been at fault to have put it in in the first place with direct solder in
the yellow wires.I am thinking of a late night scenario in this case with
one of those nifty Weller 500 watt guns that could be used with copper
water pipe and delicate electronics, and someone with no idea where fuses
came from. 
4:06 p.m.
Well, they do say that the device is there to protect the fuse...
Actually my experience relating to thsoe expensive FF fuses used in
SMPSus ios that hte chopper transsitor will fial short-circuit, thus
ensurign the fuse is destroyed too...
http://www.classiccmp.org/acornia/tmp/fuse.jpg
Found in the chassis of an old 'scope. There's actually originally no
provision for a fuse in the 'scope itself - just a circuit breaker - but
quite why someone would take the trouble to cut a wire and then solder both
ends of the same fuse to it, I have no idea.
Err, yes... I think I've seen it all now...
-tony
12 Sep
12 Sep
9:58 a.m.
On Sep 11, 2014, at 7:06 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
That reminds me of an article, perhaps in the late 1960s, in QST by John Troster, w6ISQ,
author of all manner of joke articles. The title was something along the lines of
?Murphy?s laws of electronics?.
One of them: ?A transistor, protected by a fast acting fuse, will protect the fuse by
blowing first?.
Another one: ?A dropped tool will land where it does the most expensive damage ? this is
know as the Law of Selective Gravitation?. (That came with a cartoon showing a hammer
nudged off a shelf, on a direct path to an expensive vacuum tube in an open chassis on the
bench.)
paul
Well, they do say that the device is there to protect the fuse...
Actually my experience relating to thsoe expensive FF fuses used in
SMPSus ios that hte chopper transsitor will fial short-circuit, thus
ensurign the fuse is destroyed too?
3:52 p.m.
On Sep 11, 2014, at 7:06 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
That reminds me of an article, perhaps in the late 1960s, in QST by
John Troster, w6ISQ, author of all manner of joke articles. The title
was something along the lines of ?Murphy?s laws of electronics
Yes, I've come acorss that, or soemthing very like it.Another well-known
law is :
'Any wire cut to length is too short'
Well, they do say that the device is there to protect the fuse...
Actually my experience relating to thsoe expensive FF fuses used in
SMPSus ios that hte chopper transsitor will fial short-circuit, thus
ensurign the fuse is destroyed too? One of them: ?A transistor, protected by a fast acting
fuse, will
protect the fuse by blowing first?
My point is that this does not go far enough,. If you protect a transsito
with an expensive FF fuse, then not only will the transistor fail first,
it will do so i na wat to blow the fuse. It will not protect the fuse.
That owuld be contrary to Muprhy's Law...
Another one: ?A dropped tool will land where it does the most
expensive damage ? this is know as the Law of Selective Gravitation?.
(That came with a cartoon showing a hammer nudged off a shelf, on a
direct path to an expensive vacuum tube in an open chassis on the bench.
Along with
The part you acidnetally drip will be the most expensive and/or delicate
component in the unit. It will land in such a way as to maximise damage'
-tony
3757
days inactive
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