sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

* Why use a contactor? - 8 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/8a277d142156dff2?hl=en
* 3-contact 2.5mm male - 4-contact 3.5 mm female - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/9aa8b3ae778aae08?hl=en
* Favorite Cutters For Snipping DIP Leads? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/30d89f0c2d193f6d?hl=en
* Laser fuser thermal switches? - 10 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/3e3bc34da4e7c0cf?hl=en
* 1/4" phone jack replacement for Behringer 215 speaker. - 1 messages, 1
author
http://groups.google.com/group/sci.electronics.repair/t/0fd5e32c8baa1611?hl=en
* Batt charged but unplug shuts - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/239916b681296dcf?hl=en
* CR2023? CR2032 Batteries - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/8e15ac1d36a61277?hl=en

==============================================================================
TOPIC: Why use a contactor?
http://groups.google.com/group/sci.electronics.repair/t/8a277d142156dff2?hl=en
==============================================================================

== 1 of 8 ==
Date: Mon, Jan 13 2014 7:17 am
From: Gunner Asch


On Mon, 13 Jan 2014 06:11:15 -0600, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote:

>"DoN. Nichols" <BPdnicholsBP@d-and-d.com> fired this volley in
>news:slrnld6mot.id6.BPdnicholsBP@Katana.d-and-d.com:
>
>> It is at least a *possible* one.
>
>Don, I'm not picking on your answer... I had to respond to someone's, and
>yours got the prize...
>
>
>This is the dumbest discussion I've ever heard (short of all the
>political spew on here).
>
>Even half-quality garbage plastic switches from China are NOT prone to
>accidentally 'switching on' from accumulations of dust or swarf.
>
>That it's a remote possibility, I won't deny. But such switches typically
>serve for years to decades without a malfunction in the dusty, dirty,
>swarf-filled environments in which we use them, and it's dumb to think of
>the average home craftsman's going to the trouble to re-wire, retrofit,
>and otherwise jigger-up his equipment with low voltage contactors and
>safety circuits. That some would or even could is beside the question.
>
>This discussion should be turned to "What's the best-quality switch I can
>buy affordably that will suit the safety needs of the application." For
>that, I recommend a good industrial-quality safety-style switch that
>requires a simple swipe of the hand to turn off, and a positive 'de-
>locking' action to turn on.
>
>My old (1970s) Shopsmith came with one. When I finally wore it out in
>the 1990s, I replaced it with the same-quality switch from a US maker
>(IIRC it was a Square-D safety switch, specifically for table saws). You
>could knock it off easily, but had to pull the bat out manually to turn
>it back on -- heavy-duty thing. It lasted more than 20 years of nearly
>daily use, and the replacement is still on the machine, still working.
>
>LLoyd

Last year.. I replaced 5 switches in Delta /Milwaukee table saws
alone.


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is either stupid or a perpetual societal leech"

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== 2 of 8 ==
Date: Mon, Jan 13 2014 7:19 am
From: Gunner Asch


On Mon, 13 Jan 2014 14:01:44 +0100, Leif Neland <leif@neland.dk>
wrote:

>DaveC sendte dette med sin computer:
>
>>
>> Yes, we all know about "during a power failure" but many times this won't be
>> an issue (actually the friend would appreciate the saw continuing the cut
>> after power comes back!), but the "auto turn-on" feature )c: is one I hadn't
>> thought of.
>>
>
>Why on earth would frind want the saw to turn on after a power failure?

In most cases...if the saw is running WHEN the power goes off....it
comes back on when the power returns.

With a contactor..it stays OFF if properly wired until you turn off
the switch..then turn it back on.


__
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is either stupid or a perpetual societal leech"

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== 3 of 8 ==
Date: Mon, Jan 13 2014 12:04 pm
From: Leif Neland


Gunner Asch kom med f�lgende:
> On Mon, 13 Jan 2014 14:01:44 +0100, Leif Neland <leif@neland.dk>
> wrote:
>
>> DaveC sendte dette med sin computer:
>>
>>>
>>> Yes, we all know about "during a power failure" but many times this won't
>>> be an issue (actually the friend would appreciate the saw continuing the
>>> cut after power comes back!), but the "auto turn-on" feature )c: is one I
>>> hadn't thought of.
>>>
>>
>> Why on earth would frind want the saw to turn on after a power failure?
>
> In most cases...if the saw is running WHEN the power goes off....it
> comes back on when the power returns.
>
> With a contactor..it stays OFF if properly wired until you turn off
> the switch..then turn it back on.
>
I agree, but my question is

"Why on earth would frind want the saw to turn on after a power
failure"

which OP claims "the friend would appreciate".

When the power is turned off, the material being sawed, tools, fingers
etc. could block the saw. I very much prefer the saw does *not* start
by itself.

In the circuits I've seen, the ON is a "no", normal open pushbutton,
which energizes the contactor. An on-switch on the contactor in
parallel with this provides current to the contactor.
The OFF is a "NC", normal closed pushbutton, removing the voltage to
the contactor. All kinds of safety switches could be wired in series,
all required to be closed for the saw to run.

Leif

--
Husk k�relys bagp�, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.






== 4 of 8 ==
Date: Mon, Jan 13 2014 4:52 pm
From: Gunner Asch


On Mon, 13 Jan 2014 21:04:37 +0100, Leif Neland <leif@neland.dk>
wrote:

>Gunner Asch kom med f�lgende:
>> On Mon, 13 Jan 2014 14:01:44 +0100, Leif Neland <leif@neland.dk>
>> wrote:
>>
>>> DaveC sendte dette med sin computer:
>>>
>>>>
>>>> Yes, we all know about "during a power failure" but many times this won't
>>>> be an issue (actually the friend would appreciate the saw continuing the
>>>> cut after power comes back!), but the "auto turn-on" feature )c: is one I
>>>> hadn't thought of.
>>>>
>>>
>>> Why on earth would frind want the saw to turn on after a power failure?
>>
>> In most cases...if the saw is running WHEN the power goes off....it
>> comes back on when the power returns.
>>
>> With a contactor..it stays OFF if properly wired until you turn off
>> the switch..then turn it back on.
>>
>I agree, but my question is
>
>"Why on earth would frind want the saw to turn on after a power
>failure"

I would hope that it wouldnt.
>
>which OP claims "the friend would appreciate".
>
>When the power is turned off, the material being sawed, tools, fingers
>etc. could block the saw. I very much prefer the saw does *not* start
>by itself.
>
>In the circuits I've seen, the ON is a "no", normal open pushbutton,
>which energizes the contactor. An on-switch on the contactor in
>parallel with this provides current to the contactor.
>The OFF is a "NC", normal closed pushbutton, removing the voltage to
>the contactor. All kinds of safety switches could be wired in series,
>all required to be closed for the saw to run.
>
>Leif

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== 5 of 8 ==
Date: Mon, Jan 13 2014 7:28 pm
From: "DoN. Nichols"


On 2014-01-13, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:
> "DoN. Nichols" <BPdnicholsBP@d-and-d.com> fired this volley in
> news:slrnld6mot.id6.BPdnicholsBP@Katana.d-and-d.com:
>
>> It is at least a *possible* one.
>
> Don, I'm not picking on your answer... I had to respond to someone's, and
> yours got the prize...

O.K. I won't take it personally. :-)

> This is the dumbest discussion I've ever heard (short of all the
> political spew on here).
>
> Even half-quality garbage plastic switches from China are NOT prone to
> accidentally 'switching on' from accumulations of dust or swarf.

Though some which are made to mount behind a trim plate in the
wall (typical home light switch) may be more open to a buildup of swarf
inside it. I've seen various failures in home electrical hardware which
I would not have expected.

Among those, there was an outlet which failed during a
nearby lightning strike. The form of the failure was a breakdown in the
hole into which a drive screw went to hold the ground strap which mounts
it to the outlet box. It was *supposed* to be a blind hole, but they
had used a slightly too long drive screw, or a chip was under it, and
there was a little of the inside surface which broke away.

Still -- normally not a problem. However, the lightning strike
introduced a high enough voltage so the gap to the nearby hot lead was
bridged, and the subsequent arc, both partially melted the "hot" inside
the socket, and welded it to what was plugged into it (one of those
duplex to six outlet plates) -- *and* filled the vicinity with carbon
dust.

When I got home from work and discovered the power loss in the
living room, I went downstairs and switched on the breaker. Five second
delay and BZZZZTTT-CLICK. A repeat got the same results. I then walked
around the house (old wiring, given breakers showed up in a lot of
outlets around the house.

I then walked around the house, until I smelled the burnt
Bakelite. Of course the outlet was behind a bookcase which I had to
empty and move to get to it. Then I discovered that the multi-outlet
adaptor would not unplug until I applied a lot of force, and that left
one pin of the adaptor in the socket.

I then removed the socket, and replaced it with a new one -- and
just had to take it apart to see what had happened.

If the Bakelite had not flaked around the drive screw, it would
not have broken down -- and the failure would have been somewhere else
at an even higher voltage -- or maybe not.

So -- I don't *depend* on any commercial electrical hardware for
the home to do what it should do.

And -- once I needed a toggle switch which did not introduce
vibration when it was operated to put in the mounting plate for a
turntable, so I could cue a record, and then switch on the motor at the
appropriate time. At that time, you could get "silent" light switches
which contained a puck of mercury in glass and metal end caps. It was
designed to work in a vertical orientation, but it was possible to take
the switch mounting plate off, and file different notches into the
toggle handle so it would hold the puck for horizontal operation. Now,
that switch was *not* designed to keep swarf out, so it would have to
depend on the decorative plate which goes over it. Granted, no normal
person would mount it as I did -- and I never had swarf near the
turntable, so it was no problem. But I do remember that switch, and how
easy it would be for swarf or sawdust to work its way in. Sawdust would
just make it take a bit more force to operate. Metal swarf would bridge
the ends of the puck and leave it on full time.

Granted -- most of the horizontal/vertical bandsaws use a normal
bat-handle toggle switch, but there are variations in quality there.
The best have a seal around the ball on which the bat rotate, and have
sealed wire entrance on the back. Cheap ones either have terminals on
the back (which you screw, solder wires to, or tabs for (hopefully)
insulated push-on crimp terminals -- but still metal swarf could bridge
that to the frame.

> That it's a remote possibility, I won't deny. But such switches typically
> serve for years to decades without a malfunction in the dusty, dirty,
> swarf-filled environments in which we use them, and it's dumb to think of
> the average home craftsman's going to the trouble to re-wire, retrofit,
> and otherwise jigger-up his equipment with low voltage contactors and
> safety circuits. That some would or even could is beside the question.

Given that he is already "jiggering up" the bandsaw -- replacing
the single phase 120 VAC motor with a higher horsepower single phase 240
VAC motor, you introduce another problem. Ideally (given USA wiring,
where 240 VAC is really two 120 VAC wires 180 degrees out of phase, so
they produce 240 VAC between them), you want a switch which interrupts
both sides of the power -- so a winding failure in the motor does not
leave some part of the system perhaps floating at 120 VAC instead of
near ground as it should be. Now, -- in the UK you don't normally have
240 VAC with a grounded center tap. Instead, one side of the 240 VAC is
grounded.

> This discussion should be turned to "What's the best-quality switch I can
> buy affordably that will suit the safety needs of the application." For
> that, I recommend a good industrial-quality safety-style switch that
> requires a simple swipe of the hand to turn off, and a positive 'de-
> locking' action to turn on.

*And* -- one which interrupts both sides of the line, since he
is putting in a 240 VAC motor.

> My old (1970s) Shopsmith came with one. When I finally wore it out in
> the 1990s, I replaced it with the same-quality switch from a US maker
> (IIRC it was a Square-D safety switch, specifically for table saws). You
> could knock it off easily, but had to pull the bat out manually to turn
> it back on -- heavy-duty thing. It lasted more than 20 years of nearly
> daily use, and the replacement is still on the machine, still working.

Good enough. Remember that the motor is being changed here, so
at least some change in the switch is called for.

For special switches, somewhere I still have a switch designed
for reversing a single phase motor. It runs in either direction
(reversing two of the three circuits), but it enforces a pause when
switching from one direction to the other -- since running single phase
motors can't be instantly reversed just by swapping two wires. They
have to be allowed to slow down enough to come to a near halt (enough so
the centrifugal switch closes to enable the start winding for the
reversal.)

So -- yes with the right switches -- no problem. However, if
you want the weight of the arm of a horizontal/vertical bandsaw to
switch it off (at least he 4x6" ones) -- you want a switch with not much
operating force -- which is less likely to be capable of switching both
sides of the line for the 240 VAC motor. (I'm still not sure why he
feels the need for a larger motor -- perhaps it was one of those Chinese
import motors which are almost all empty housing, and very little frame,
made to *look* like a bigger motor, but bound to burn out with any
serious use. My 4x6 HV bandsaw came from MSC, and apparently they
spec'd a better quality motor -- and that one is still running, and does
not get hand-burning hot with a long cut. :-) So perhaps all he needs is
a motor which really is the nameplate horsepower on what he had -- and
for that, a 120 VAC motor should be sufficient and the original switch
might even do well. (I'll have to look under the base of mine to see
what the switch looks like there. :-)

Enjoy,
DoN.

--
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Email: <BPdnicholsBP@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
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== 6 of 8 ==
Date: Mon, Jan 13 2014 7:39 pm
From: "DoN. Nichols"


On 2014-01-13, David Billington <djb@djbillington.freeserve.co.uk> wrote:
> On 13/01/14 12:11, Lloyd E. Sponenburgh wrote:

[ ... ]

>> That it's a remote possibility, I won't deny. But such switches typically
>> serve for years to decades without a malfunction in the dusty, dirty,
>> swarf-filled environments in which we use them, and it's dumb to think of
>> the average home craftsman's going to the trouble to re-wire, retrofit,
>> and otherwise jigger-up his equipment with low voltage contactors and
>> safety circuits. That some would or even could is beside the question.
>
> What's the benefit of a low voltage contactor and safety circuit? I have
> various equipment with safety circuits and they use either the 230V or
> 415V supply for the contactor and safety circuit.

Routing the wiring around the machine tool to provide both the
"stop" switch at the end of cut condition, and multiple "stop" buttons
within convenient reach if something goes wrong, plus more than one
start button as well. With no high voltage on those (if design makes the
back easy to contact). You can use smaller gauge wire to route it where
you need it without adding stiffness to the machine's movement. (I
would like stop and start buttons on the moving arm of the H/V bandsaw,
so I don't have to bend over as far to reach the power switch.) But
this is just me. :-)

Even the Chinese 12x40" lathes have relays and a transformer to
provide the control voltages at 24V instead of the 120 or 240 VAC (the
latter more likely for that large a lathe). And -- the wiring might be
for 480 VAC as well, depending on where the machine will be installed.
Just move some jumpers to change operation from 240 VAC to 480 VAC, and
the control buttons don't get any more voltage than 24 VAC.

I discovered how this was set up when I helped a friend convert
his to a three-phase motor with a VFD. Even added a "jog" feature to
enable rotating the chuck until the proper wrench socket is facing out. :-)

And the VFD actually uses even lower voltages -- 5 VDC or at
worst 10 VDC for all the signal leads.

Enjoy,
DoN.

--
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--- Black Holes are where God is dividing by zero ---




== 7 of 8 ==
Date: Mon, Jan 13 2014 7:42 pm
From: "DoN. Nichols"


On 2014-01-13, Gunner Asch <gunnerasch@gmail.com> wrote:
> On Mon, 13 Jan 2014 06:11:15 -0600, "Lloyd E. Sponenburgh"
><lloydspinsidemindspring.com> wrote:

[ ... ]

>>My old (1970s) Shopsmith came with one. When I finally wore it out in
>>the 1990s, I replaced it with the same-quality switch from a US maker
>>(IIRC it was a Square-D safety switch, specifically for table saws). You
>>could knock it off easily, but had to pull the bat out manually to turn
>>it back on -- heavy-duty thing. It lasted more than 20 years of nearly
>>daily use, and the replacement is still on the machine, still working.
>>
>>LLoyd
>
> Last year.. I replaced 5 switches in Delta /Milwaukee table saws
> alone.

Wood sawdust packed in the switches? What kind of switches?
Perhaps the standard wall switch?

Did you take them apart for the fun of finding out what the
failure mode was? (Detail photos would go a long way towards settling
the debate ranging here. But at least is is about *metalworking*
(and woodworking), not politics.

Enjoy,
DoN.

--
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Email: <BPdnicholsBP@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---




== 8 of 8 ==
Date: Mon, Jan 13 2014 7:48 pm
From: "DoN. Nichols"


On 2014-01-13, Ignoramus28861 <ignoramus28861@NOSPAM.28861.invalid> wrote:
> On 2014-01-13, DoN. Nichols <BPdnicholsBP@d-and-d.com> wrote:
>> On 2014-01-12, Ignoramus13867 <ignoramus13867@NOSPAM.13867.invalid> wrote:
>>
>> [ ... ]
>>> The best argument for using a contactor in a small bandsaw, is that
>>> you can get proper thermal overloads to protect the motor.
>>
>> This is more of a factor with three phase motors, where a motor
>> once started will continue to run if one phase of power fails, but the
>> current drawn in each remaining winding will be higher, and will be
>> likely to burn out the motor. (And he was going to add a 240 VAC single
>> phase motor to the bandsaw in question.)
>
> No, on bandsaw, the main problem is that it runs unattended and can
> easily get stuck.

O.K. I've not experienced that on mine -- but given some of the
motors on the import H/V bandsaws, that is a possibility. And *that* is
a good reason for replacing the motor with one which delivers the
nameplate horsepower, instead of being mostly empty air in a too-large
housing trying to look like an adequate motor. :-) I've read the reports
of motors getting so hot that they burn the hands of the user, but mine
never gets that hot. MSC got a proper motor put into it, apparently.

Enjoy,
DoN.

--
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Email: <BPdnicholsBP@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
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==============================================================================
TOPIC: 3-contact 2.5mm male - 4-contact 3.5 mm female
http://groups.google.com/group/sci.electronics.repair/t/9aa8b3ae778aae08?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Jan 13 2014 7:33 am
From: dave


On 01/12/2014 06:05 PM, vjp2.at@at.BioStrategist.dot.dot.com wrote:
> I got an Iphone headset which has four contacs on a phone plug.
> But the phone uses a normal 3-contact universal handsfree.
>
> I have bought numerous adaptors but they don't seem to work.
> I can hear the phone, but I can't be heard.
>
> I am now tempted to make the adaptors myself. How do you spec them?
> Would places like Mouser have them or are they still too new?
>
> - = -
> Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
> http://www.panix.com/~vjp2/vasos.htm
> ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
> [Homeland Security means private firearms not lazy obstructive guards]
> [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
>
I have a Yaesu adaptor for handheld transceivers that has the 4 chan
male 3.5mm to a stereo 3.5mm Female and a mono 3.5mm





== 2 of 3 ==
Date: Mon, Jan 13 2014 10:41 am
From: Adrian C


On 13/01/2014 02:05, vjp2.at@at.BioStrategist.dot.dot.com wrote:
> I got an Iphone headset which has four contacs on a phone plug.
> But the phone uses a normal 3-contact universal handsfree.
>
> I have bought numerous adaptors but they don't seem to work.
> I can hear the phone, but I can't be heard.
>
> I am now tempted to make the adaptors myself. How do you spec them?
> Would places like Mouser have them or are they still too new?

What color is your phone? How heavy is it? Does the IMEI end with a C or
a Z?

--
Adrian C






== 3 of 3 ==
Date: Mon, Jan 13 2014 11:44 am
From: "William Sommerwerck"


Have you considered getting a new phone? I was trying to make a four-pin
handset work on a three-pin cell phone around the time I decided to switch to
another provider. The phone that came with the change had a four-pin jack, and
everything worked fine.






==============================================================================
TOPIC: Favorite Cutters For Snipping DIP Leads?
http://groups.google.com/group/sci.electronics.repair/t/30d89f0c2d193f6d?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jan 13 2014 8:50 am
From: "Michael A. Terrell"



N_Cook wrote:
>
> On 11/01/2014 16:46, Kaz Kylheku wrote:
> > On 2014-01-11, Doug White <gwhite@alum.mit.edu> wrote:
> >>> 0.5mm thick abrasive disc or cintride/"diamond" disc in a "Dremmel"
> >>
> >> Thus throwing small conductive bits all over the board. No thanks...
> >
> > Reconsider your objection. You can blow the filings away with compressed air,
> > and vacuum up.
> >
> > The board is not powered up while you're doing this, right?
> >
> > You could also mask the board off with a piece of paper (or whatever) that has
> > a cutout just for the IC, if you're paranoid.
> >
>
> Its not as though the bits of metal grow dendrite or tin-whisker
> fashion. You'd have to be extremly unlucky to end up with a continous
> patch of dozens of minute particles forming a continuous path.
> Similar situation with solder paste, you cannot guarantee making all
> those tiny balls molten and aggregate together as one


Really? You ever test new boards, right out of the reflow oven? A lot
of lead to lead shorts from balls of solder trapped under the IC's leads
if the reflow profile, paste solder and a dozen other things aren't
exactly right. I've removed hundreds of them from new boards. Metal dust
doesn't have to make good connections to cause problems. I had a batch
of new embedded computer boards come from the vendor with a problem. It
wasn't caught at incoming inspection, so we stuffed and reflowed them.
The were erratic as hell. I found the problem. The PCB house had
scratched the film along a +5V rail. This was arching to the parallel
ground plane, and right next to the input of an ADC. Know it alls claim
you can't have an arc at that voltage. All you need is enough potential
to jump the gap.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.




== 2 of 2 ==
Date: Mon, Jan 13 2014 3:08 pm
From: "Rick"



"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:lau958$lkd$1@dont-email.me...
>I did this a few years ago when I had to remove a DIP and a five-lead
>TO-cased buffer from the top of a board.
>
> The TO package came lose with a pair of cutters. I don't remember how I
> removed the DIP, but I'm pretty certain I used a cutoff disk. (Even if you
> have fine-tipped cutters, you run the risk of damaging the board from the
> force exerted.) I don't remember what I did about the fine shavings (if
> there were any).

I have been using this from Home Depot
www.homedepot.com/p/Xcelite-4-in-Shear-Cutter-Plier-Set-2-Piece-S2KS5/100163974?keyword=s2ks5#.UtRwxiFEOgM

They are only $ 13.97 and include a needle nose pliers. They cut dip leads
just fine and are cheap enough to keep a few sets around. It is a good
bench set of tools.







==============================================================================
TOPIC: Laser fuser thermal switches?
http://groups.google.com/group/sci.electronics.repair/t/3e3bc34da4e7c0cf?hl=en
==============================================================================

== 1 of 10 ==
Date: Mon, Jan 13 2014 11:57 am
From: T i m


Hi all,

I fault found (what I believe is) an open cct thermal switch in the
fuser of a 'faulty' Samsung CLX 3175 laser printer I was recently
given.

https://dl.dropboxusercontent.com/u/5772409/Thermal%20switch.jpg

One is marked 170/0 100209 and the other is unmarked.

Because it looks like there are two in series, as a test I shorted one
out and the printer fired up and seemed to work ok. ;-)

So, am I right in thinking there are two in series as a failsafe and
they are used as an overtemp and that the actual temperature might be
managed by a thermister and finer / electronic (PWM?) controls?

I believe I could buy a new fuser at a reasonable price and that would
obviously come with a pair of new thermal switches but as the fuser is
otherwise working it would be nice if I could simply replace this
faulty device (and if so from where please)?

Cheers, T i m




== 2 of 10 ==
Date: Mon, Jan 13 2014 12:06 pm
From: jurb6006@gmail.com


I think the fuser temperature is pretty much determined by its current draw (resistance) and any control is simply on or off. Looks like those are just to kep it from burning the house down.

Why there are two is a mystery to me. Maybe it consists of two elements in series and if one shorts it would trigger ? Something like that ?




== 3 of 10 ==
Date: Mon, Jan 13 2014 12:31 pm
From: mroberds@att.net


T i m <news@spaced.me.uk> wrote:
> I fault found (what I believe is) an open cct thermal switch in the
> fuser of a 'faulty' Samsung CLX 3175 laser printer I was recently
> given. [...]
>
> So, am I right in thinking there are two in series as a failsafe

This is probably true.

> and they are used as an overtemp

Could be an overtemp, could be a normal operating control. Sometimes
there will be an "operating" thermostat at X degrees C in series with
a "limit" thermostat at (say) X+20 degrees C. In this configuration,
sometimes the operating thermostat is designed to turn on and off
indefinitely, but the limit thermostat is more of a thermal fuse - it
opens the circuit once and stays open forever after that.

> and that the actual temperature might be managed by a thermister and
> finer / electronic (PWM?) controls?

Maybe. It could be that the electronic control has also failed for some
reason, such that the printer appears to work in a short test, but if
you leave it on for a long time or run a long print job, it might
overheat again. If you do replace the switch, it's probably a good idea
to run the first several print jobs while you/someone is nearby, to shut
off the printer in case of excitement.

> I believe I could buy a new fuser at a reasonable price and that would
> obviously come with a pair of new thermal switches but as the fuser is
> otherwise working it would be nice if I could simply replace this
> faulty device (and if so from where please)?

That looks like the Korean interpretation of a Klixon 7BT2 thermostat.
They are available in a variety of mounting options and terminal types,
but all with pretty much the same size body.
http://www.sensata.com/klixon/thermostat-precision-7bt2.htm

The White-Rodgers 3L11 series is similar, but the ones I can find
quickly all have a mounting foot, which you may not need in your
application. These are distributed in small quantities by Mouser (US):
http://www.mouser.com/ProductDetail/White-Rodgers/3L11-325/?qs=sGAEpiMZZMusbZ2pNxAMx%2f729FK%252btZH%2fyKEVnol6%252b%2f4%3d
(or search 3L11-325 at mouser.com)

Cantherm R53 series also appears to be similar. These are distributed
in small quantities by Digi-Key (US):
http://www.digikey.com/product-detail/en/CS715025Z/317-1553-ND
The ones Digi-Key sells come with a mounting flange, but it looks like
it would be easy to remove this with pliers.

Hopefully the "170" in the part number on yours means 170 C, but it
would be good to find out for sure.

It looks like your two thermostats have been joined by spot-welding the
terminals; you may have to replace both thermostats and come up with a
way to join the terminals on your own - a really short jumper wire,
perhaps.

In the US, these are all over the place inside home refrigerators,
clothes dryers, etc. An appliance repair shop will probably have some,
but they will probably only know them by the manufacturer part number
and not just the fact that it's for 170 C or whatever.

Standard disclaimers apply: I don't get money or other consideration
from any companies mentioned.

Matt Roberds





== 4 of 10 ==
Date: Mon, Jan 13 2014 12:33 pm
From: T i m


On Mon, 13 Jan 2014 12:06:21 -0800 (PST), jurb6006@gmail.com wrote:

>I think the fuser temperature is pretty much determined by its current draw (resistance) and any control is simply on or off.

Ok.

> Looks like those are just to kep it from burning the house down.

;-)

>Why there are two is a mystery to me. Maybe it consists of two elements in series and if one shorts it would trigger ? Something like that ?

Don't think so in this case as these thermal switches are connected in
series and with no other connections etc, and I can only see the ends
for one heater / lamp?

https://dl.dropboxusercontent.com/u/5772409/Fuser.jpg

I think the two in series is as you say and a safety thing ... and as
only one is marked they are possibly both the same temperature rating.

I have seen n/c thermal switches and assuming 170 marking is the
temperature in Centigrade, I could potentially get a similar
replacement but they are set in holes and facing the fuser roller so
the dimensions could be reasonably critical.

I guess I could just run the printer, turning it on and off as
required and if it seems reliable / useful, treat it to a new fuser in
any case?

Cheers, T i m




== 5 of 10 ==
Date: Mon, Jan 13 2014 1:34 pm
From: T i m


On Mon, 13 Jan 2014 20:31:01 +0000 (UTC), mroberds@att.net wrote:

>T i m <news@spaced.me.uk> wrote:
>> I fault found (what I believe is) an open cct thermal switch in the
>> fuser of a 'faulty' Samsung CLX 3175 laser printer I was recently
>> given. [...]
>>
>> So, am I right in thinking there are two in series as a failsafe
>
>This is probably true.
>
>> and they are used as an overtemp
>
>Could be an overtemp, could be a normal operating control. Sometimes
>there will be an "operating" thermostat at X degrees C in series with
>a "limit" thermostat at (say) X+20 degrees C. In this configuration,
>sometimes the operating thermostat is designed to turn on and off
>indefinitely, but the limit thermostat is more of a thermal fuse - it
>opens the circuit once and stays open forever after that.

Ah, that makes sense and was another option I considered (and the code
on the pair could have been a Samsung part number for the two devices
combined as a 'solution' (they are cold welded together with a
bridging plate).
>
>> and that the actual temperature might be managed by a thermister and
>> finer / electronic (PWM?) controls?
>
>Maybe. It could be that the electronic control has also failed for some
>reason, such that the printer appears to work in a short test, but if
>you leave it on for a long time or run a long print job, it might
>overheat again.

The paper certainly comes out pretty warm but then I think this is the
case when they have upped the page rate? The paper isn't curled etc,
if that says anything?

>If you do replace the switch, it's probably a good idea
>to run the first several print jobs while you/someone is nearby, to shut
>off the printer in case of excitement.

Hehe. I have probably put 60 pages though it whilst testing today and
it seems to have survived that ok. However and as I mentioned just,
the paper did feel pretty warm (I can put the IR thermometer on it and
see what sort of temps are going on).
>
>> I believe I could buy a new fuser at a reasonable price and that would
>> obviously come with a pair of new thermal switches but as the fuser is
>> otherwise working it would be nice if I could simply replace this
>> faulty device (and if so from where please)?
>
>That looks like the Korean interpretation of a Klixon 7BT2 thermostat.
>They are available in a variety of mounting options and terminal types,
>but all with pretty much the same size body.
>http://www.sensata.com/klixon/thermostat-precision-7bt2.htm

<checks link> Thanks for that, plenty of choice there. I did have a
quick look for a Service Manual as there may well be some calibration
/ temperature measurements in there but as yet, only have the parts
section (with exploded diagrams).
>
>The White-Rodgers 3L11 series is similar, but the ones I can find
>quickly all have a mounting foot, which you may not need in your
>application. These are distributed in small quantities by Mouser (US):
>http://www.mouser.com/ProductDetail/White-Rodgers/3L11-325/?qs=sGAEpiMZZMusbZ2pNxAMx%2f729FK%252btZH%2fyKEVnol6%252b%2f4%3d
>(or search 3L11-325 at mouser.com)
>
>Cantherm R53 series also appears to be similar. These are distributed
>in small quantities by Digi-Key (US):
>http://www.digikey.com/product-detail/en/CS715025Z/317-1553-ND
>The ones Digi-Key sells come with a mounting flange, but it looks like
>it would be easy to remove this with pliers.

Again, that was something I also considered.
>
>Hopefully the "170" in the part number on yours means 170 C, but it
>would be good to find out for sure.

I guess I could test the remaining working one with a DMM, heat gun
and IR thermometer?
>
>It looks like your two thermostats have been joined by spot-welding the
>terminals; you may have to replace both thermostats and come up with a
>way to join the terminals on your own - a really short jumper wire,
>perhaps.

Understood.
>
>In the US, these are all over the place inside home refrigerators,
>clothes dryers, etc. An appliance repair shop will probably have some,
>but they will probably only know them by the manufacturer part number
>and not just the fact that it's for 170 C or whatever.

Also understood. I have changed such (and thermal fuses) on a few
things now.
>
>Standard disclaimers apply: I don't get money or other consideration
>from any companies mentioned.

Understood. ;-)

As the fuser comes as an assembly and therefore no sub-part
information is available, I might just run the printer as-is for a
while (switching on and of as required) and if it proves reliable,
then maybe treating it to a new fuser in any case. At least that way I
might be able to see if there are any more useful markings on the new
one and if so, see if they are indeed just in duplicate (switch +
switch) or as you say, something more final, like switch + thermal
fuse (and have the old fuser for other spares). ;-)

Cheers and thanks for all the links etc.

T i m.




== 6 of 10 ==
Date: Mon, Jan 13 2014 3:11 pm
From: jurb6006@gmail.com


The main reason I figured the temperature is self regulating is that the fuser is one of those parts that are different on a 120 volt unit or a 240 volt unit. It probably just kicks on with a relay.

I could be wrong, but I doubt they could get precise enough temperature control out of one of those little bimetal jobs to assure consistent print quality.

Of ocurs eI could be wrong, but there is still usually a different part for 24 volt operation, whereas most modern power supplies switch automatically. Some don't even need to switch, they just have good enough regulation to run fine anywhere from 50 - 250 VAC.




== 7 of 10 ==
Date: Mon, Jan 13 2014 3:15 pm
From: Jeff Liebermann


On Mon, 13 Jan 2014 19:57:41 +0000, T i m <news@spaced.me.uk> wrote:

>I fault found (what I believe is) an open cct thermal switch in the
>fuser of a 'faulty' Samsung CLX 3175 laser printer I was recently
>given.

What is "faulty" about the Samsung CLX 3175 printer?
Are you getting an error message on the front panel?
Is it perhaps a "Deve Home Sensor Error" message?

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558




== 8 of 10 ==
Date: Mon, Jan 13 2014 3:27 pm
From: T i m


On Mon, 13 Jan 2014 15:15:11 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Mon, 13 Jan 2014 19:57:41 +0000, T i m <news@spaced.me.uk> wrote:
>
>>I fault found (what I believe is) an open cct thermal switch in the
>>fuser of a 'faulty' Samsung CLX 3175 laser printer I was recently
>>given.
>
>What is "faulty" about the Samsung CLX 3175 printer?

Nothing now. ;-)

>Are you getting an error message on the front panel?

I was.

>Is it perhaps a "Deve Home Sensor Error" message?

No, it was something about cycling the power (that made no difference)
but a Goggle search from that suggested a fuser fault (as one of the
main causes).

The fuser was indeed cold and (as it turned out) because of what looks
like a thermal switch (or fuse) that had gone o/c. Shorting said
device with some copper wire removed the error message and allowed the
printer to return to a working condition. ;-)

That said, because I don't know of the type / function of the o/c
device, I now may not have either:

1) The extra safety functionality (thermal fuse)

2) The right running temperature (two different temperature threshold
devices in series and the lower temp unit has failed).

As what is probably and aside I'm also seeing a horizontal band across
the page. It could be off the OPC drum. I'll have to measure the
circumference but it looks about right.

Cheers, T i m







== 9 of 10 ==
Date: Mon, Jan 13 2014 3:44 pm
From: T i m


On Mon, 13 Jan 2014 15:11:46 -0800 (PST), jurb6006@gmail.com wrote:

>The main reason I figured the temperature is self regulating is that the fuser is one of those parts that are different on a 120 volt unit or a 240 volt unit.

Understood.

> It probably just kicks on with a relay.

I think I read somewhere that someone had changed a thyristor (triac?)
on the SMPS but it could be used in the same on/off way of course.

This is the PSU:

https://dl.dropboxusercontent.com/u/5772409/Samsung%20PSU.jpg

The input (240V in this case (UK)) is in the bottom left and the
output to the fuser on the bottom right.
>
>I could be wrong, but I doubt they could get precise enough temperature control out of one of those little bimetal jobs to assure consistent print quality.

That was what I was thinking and why I wondered if the thermistor
(that also sits over the fuser roller and beside the thermal switches
/ fuse) may control it more finely. Mind you, even the temperature
range you might see with something with the hysteresis of a bi-metal
switch may not be sufficient to affect the ability to fuse toner (I
don't know if that is the case etc).
>
>Of ocurs eI could be wrong, but there is still usually a different part for 24 volt operation,

There is indeed (assuming you meant 240V there). I have seen them both
in the parts list and the voltage would (of course) affect both the
rating of the heater / lamp and the thermal switch (working voltages,
although they would probably be 240 in either case).


> whereas most modern power supplies switch automatically. Some don't even need to switch, they just have good enough regulation to run fine anywhere from 50 - 250 VAC.

Clever aren't they. ;-)

Cheers, T i m




== 10 of 10 ==
Date: Mon, Jan 13 2014 4:51 pm
From: Jeff Liebermann


On Mon, 13 Jan 2014 23:27:47 +0000, T i m <news@spaced.me.uk> wrote:

>No, it was something about cycling the power (that made no difference)
>but a Goggle search from that suggested a fuser fault (as one of the
>main causes).

Duz this sound familiar?
<http://www.fixyourownprinter.com/forums/printer/72871>
See 2nd to last comment near bottom of page. That's my favorite fix
of mechanical thermostats.

>The fuser was indeed cold and (as it turned out) because of what looks
>like a thermal switch (or fuse) that had gone o/c. Shorting said
>device with some copper wire removed the error message and allowed the
>printer to return to a working condition. ;-)

Finding the exact replacement has been a bit of a challenge. This is
the best I can do for now:
<http://www.alibaba.com/product-gs/982359539/PT056_Replacement_for_Samsung_4623_1666.html>
which isn't going to be easy to obtain. The CLX-3175FN manual shows
the part as a 4712-001027 but that's a single thermostat, not a
double. Incidentally, on the exploded view of the fuser, there's an
thermistor-NTC which is what probably controls the temperature.

>As what is probably and aside I'm also seeing a horizontal band across
>the page. It could be off the OPC drum. I'll have to measure the
>circumference but it looks about right.

If the fuser wasn't getting hot, but the mechanism was still moving,
then you could have a nice pile of toner piled up in or under the
fuser. Remove and clean.

Note: I don't fix or like Samsung printers.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558





==============================================================================
TOPIC: 1/4" phone jack replacement for Behringer 215 speaker.
http://groups.google.com/group/sci.electronics.repair/t/0fd5e32c8baa1611?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 13 2014 12:24 pm
From: "David Farber"


Gareth Magennis wrote:
> "David Farber" <farberbear.unspam@aol.com> wrote in message
> news:lasrd8$btm$1@dont-email.me...
>> This Behringer 215 speaker has two 1/4" phone jacks that are wired in
>> parallel. It also has two Speakon jacks wired in parallel to
>> facilitate adding extra speakers to the system. The unit came to me
>> with one broken 1/4" phone jack. The picture of the pc board is here.
>> http://webpages.charter.net/mrfixiter/images/Electronics/Behringer/pc-board.jpg
>
>
>
> David,
>
> I have just found a switched jack socket in my workshop similar to the
> Switchcraft style ones in your photo.
> Looking at the left PCB print in your photo, the one I have here
> connects the jack centre pin to the "12 O'clock" contact and the jack
> ground to the "7 O'clock contact. However, inserting the jack also
> connects the jack ground to the "3 O'clock" contact, meaning jack
> centre pin and ground are shorted together since the PCB has 12
> O'clock and 3 O'clock positions shorted.
> Remove this shorting on the PCB and your socket will probably work OK.
>
> Alternatively, just remove the 3 Oclock pin from the socket, though
> the first method is much safer and more sensible.
>
>
> Cheers,
>
> Gareth.

Hi Gareth,

I called Behringer parts back this morning and told them I received the
wrong parts and why they were the wrong parts. I got a call back after some
research was done and they are shipping me the correct parts this time. They
can't mess this order up twice, can they? (-:

The pc board is multi-layered so I really don't want to mess with that.
Let's see if the replacement parts are the correct ones.

Thanks for your reply.
--
David Farber
Los Osos, CA







==============================================================================
TOPIC: Batt charged but unplug shuts
http://groups.google.com/group/sci.electronics.repair/t/239916b681296dcf?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 13 2014 1:09 pm
From: Jerry Peters


vjp2.at@at.biostrategist.dot.dot.com wrote:
> It is an Acer Aspire running Linpus not Windows.
>
> I do have an identical machine which runs Windows so I might be able to swap
> batteries. I see no obvious battery compartment, so I imagine I have to open
> the unit.

The battery is at the back. There are 2 latches that hold it in place
just in front of the rear feet. Slide the latches to release the
battery and it should pull straight out.

>
> What happened is I played with the OS, trying to install a diff version of
> Linux (Quantian/Knoppix/Debian) and ended up having to reinstall Linpus from
> CD. It may have needed a larger SD card as secondary disk - I got one but
> can't set it up just yet. So I didn't use it for about two years. It was
> fine before that. Linpus is a Fedora variant and I have run into repomd
> dependency chaos, so I might install a different OS, unless I can just run
> Java apps. But I can't play with the machine for a few months until the
> current project I am using it for ends.

I've got a 16G SDHC card, /home & /var are on it, everything else is
on the internal SSD. I replaced Linpus after a week or two with my
standard Slackware install, which has since been changed to Salix
13.37 (a Slackware derivative). Bought it originally for travelling,
but it's also convenient for reading mail and newsgroups sitting in my
living room recliner.

>
> I like the size of these Acer Aspire Ones. They are great as Notebooks for
> reading PDFs and writing notes, but not much else (too slow on XP, but linpus
> is quite fast - which actually promotes the Java options). I don't like the
> idea of carrying around something expensive in NYC. I had a similarly sized
> Compaq Aero 4/25 runnign DOS for ten years and I liked it for the same
> reasons, but it also had a bum battery (ev'tho I replaced batt) so I had to
> use it always plugged in in the living room. The LED died in 12/08 the same
> week my desktop LED screen also died (wierd, never figured, prolly some kind
> of solar storm, tho bothscreens died during light drizzle outdoors - no
> machines not wet).
>
> - = -
> Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
> http://www.panix.com/~vjp2/vasos.htm
> ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
> [Homeland Security means private firearms not lazy obstructive guards]
> [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
>
>
>
>





==============================================================================
TOPIC: CR2023? CR2032 Batteries
http://groups.google.com/group/sci.electronics.repair/t/8e15ac1d36a61277?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 13 2014 8:44 pm
From: stratus46@yahoo.com



Today we received the 2032 cells from Digikey. 100 pcs Panasonic for $19.25.

Don't pay those horrible drugstore prices.

G²




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