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

sci.electronics.repair@googlegroups.com

Today's topics:

* Favorite Cutters For Snipping DIP Leads? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/30d89f0c2d193f6d?hl=en
* 1/4" phone jack replacement for Behringer 215 speaker. - 8 messages, 3
authors
http://groups.google.com/group/sci.electronics.repair/t/0fd5e32c8baa1611?hl=en
* Why use a contactor? - 12 messages, 9 authors
http://groups.google.com/group/sci.electronics.repair/t/8a277d142156dff2?hl=en
* CR2023? CR2032 Batteries - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/8e15ac1d36a61277?hl=en
* Yamaha Stagepas 500W - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/ffe9b12e2d51ee46?hl=en
* 3-contact 2.5mm male - 4-contact 3.5 mm female - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/9aa8b3ae778aae08?hl=en

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

== 1 of 2 ==
Date: Sun, Jan 12 2014 6:57 pm
From: ggherold@gmail.com


On Friday, January 10, 2014 9:40:47 PM UTC-5, Doug White wrote:
> I have occasional need to cut the leads on a standard DIP to remove it
> from a PCB. If the chip is dead or not worth saving, and the circuit
> board is delicate, I'd rather cut the leads & pull them one at a time
> rather than risk damaging the board trying to yank it all at once.
>
> The catch is that my pointiest cutters are a bit broad, and won't really
> fit down between the leads far enough to get a good cut. The ones I
> have are Utica 582E angle tip cutters, similar to these:
>
>
>
> http://www.stanleysupplyservices.com/erem-angled-tip-cutters/g/329
>
> Given the cost of a really good pair of cutters, and the generally poor
> quality of the pictures/descriptions supplied by most tool vendors, I'd
> rather not blow big bucks on them sight unseen.
>
> Does anyone have a particular make & model they can recommend?
>
> Thanks!
> Doug White

I've got a decent set of cutters that I took to the grinding wheel,
and trimped down the 'bits' that where in the way.
I use them for SMD dips too.

George H.




== 2 of 2 ==
Date: Sun, Jan 12 2014 10:32 pm
From: John Robertson


On 01/11/2014 11:38 AM, Edward Knobloch wrote:
> On 1/10/2014 9:40 PM, Doug White wrote:
>> I have occasional need to cut the leads on a standard DIP to remove it
>> from a PCB. If the chip is dead or not worth saving, and the circuit
>> board is delicate, I'd rather cut the leads& pull them one at a time
>> rather than risk damaging the board trying to yank it all at once.
> <snip>
>> Does anyone have a particular make& model they can recommend?
>
> Hi,
>
> I like the Xcelite model 170M
>
> http://www.amazon.com/Xcelite-170M-General-Shearcutter-Diagonal/dp/B0002BBZIS
>
>
> 73,
> Ed Knobloch
>

Yes, those Xceltie snips are our cutters of choice in our shop too.

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."





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

== 1 of 8 ==
Date: Sun, Jan 12 2014 7:08 pm
From: "William Sommerwerck"


"Gareth Magennis" wrote in message news:o7FAu.1651$2j5.1005@fx02.am4...

> William, why do you keep doing this?

Do what?


> If you had bothered to do your research properly you will have
> discovered that the Behringer B215 is a loudspeaker.
> It has no internal amplifiers, the jack sockets are simply in
> parallel with the Speakon sockets and do exactly the same job.

I did do my research properly, because I knew I would be subjected to this
crap. Did you look at the B215 link I supplied? The B215 is A POWERED SPEAKER,
and the 1/4" phone jack is a balanced input. READ WHAT IT SAYS on the Details
tab.

If there's something wrong, it's with Berenger's product sheet -- not my
ability to read or understand it. Or perhaps David Farber gave the wrong model
number. This might very well be the case, because the drawing doesn't show a
Speakon connection.

I normally don't ask for apologies -- but in this case, I'll make an
exception. Someone owes me an apology. Don't tell me I don't know how to
interpret a product sheet.





== 2 of 8 ==
Date: Sun, Jan 12 2014 7:17 pm
From: "William Sommerwerck"


"Phil Allison" wrote in message news:bjgu42FpsslU1@mid.individual.net...

> Clearly there is a problem with the replacement jack socket that
> seems to provide a short with a mono jack plug inserted in it.

** Yep -- it's a stereo jack with the ring contact wired to the
tip contact via the PCB.

Now, why would any manufacturer in its right mind wire a stereo jack -- input
or output -- in such a way that inserting a mono plug would short out the
signal? Oh, wait -- it's Behringer.





== 3 of 8 ==
Date: Sun, Jan 12 2014 7:34 pm
From: "Phil Allison"



"William Sommerwanker"

>
> I did do my research properly, because I knew I would be subjected to this
> crap. Did you look at the B215 link I supplied? The B215 is A POWERED
> SPEAKER, and the 1/4" phone jack is a balanced input. READ WHAT IT SAYS on
> the Details tab.


** The B215 is a passive speaker - as stated at the top of the first page
of the link.

http://www.behringer.com/EN/Products/B215.aspx

Says: " * 2 professional speaker connectors (compatible with Neutrik Speakon
connectors) plus �'' jack connectors."


The "details" tab give you a different model - the B215D which
incorporates a class D amplifier.

The OP made it VERY clear which model he was on about.




.... Phil







== 4 of 8 ==
Date: Sun, Jan 12 2014 7:39 pm
From: "Phil Allison"



"William Sommerwanker SNIPPING MANIAC "
>
>
> "Phil Allison"
>> Clearly there is a problem with the replacement jack socket that
>> seems to provide a short with a mono jack plug inserted in it.
>
> ** Yep -- it's a stereo jack with the ring contact wired to the
> tip contact via the PCB.
>
>
> Now, why would any manufacturer in its right mind wire a stereo jack

** But no manufacturer did.

The OP did that himself when he fitted the wrong part.

Which is obvious if you read the fucking post un SNIPPED !!!!!!!!!!




.... Phil








== 5 of 8 ==
Date: Mon, Jan 13 2014 2:15 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bjgu42FpsslU1@mid.individual.net...
>
> "Gareth Magennis"
>
>>
>> William, why do you keep doing this?
>
> ** The Sommerwanker fails to read his own words, let alone other's.
>
>>
>> If you had bothered to do your research properly you will have discovered
>> that the Behringer B215 is a loudspeaker.
>
> ** The heading alone makes that clear.
>
> Then the pic backs it up.
>
>> It has no internal amplifiers, the jack sockets are simply in parallel
>> with the Speakon sockets and do exactly the same job.
>
> ** But Speakons do it way better and are not prone to shorting.
>
>
>> Clearly there is a problem with the replacement jack socket that seems to
>> provide a short with a mono jack plug inserted in it.
>
> ** Yep - it a stereo jack with the ring contact wired to the tip contact
> via the PCB.
>
>
> ... Phil
>
>


It may be easiest in this case to use this "wrong" socket by modifying the
PCB traces, thus retaining the mounting between PCB and backplate and having
an easily replaceable part in the future.

It is not uncommon now to find chinese manufactured parts that look very
similar to off the shelf western parts but having different pinouts. I seem
to remember our Mr Cook reporting something along these lines here a while
ago (TRS = RTS?)

One I saw recently was a PCB mount switched jack socket where the switched
terminals were on the opposite side of the socket to just about every other
switched jack socket in existance, so the switching action would not work
with a generic replacement, even though it fitted perfectly.
(this was either a Laney or Crate guitar combo)

Seems this may be the case here.



Gareth.






== 6 of 8 ==
Date: Mon, Jan 13 2014 3:45 am
From: "Phil Allison"



"Gareth Magennis"
>
>
> One I saw recently was a PCB mount switched jack socket where the switched
> terminals were on the opposite side of the socket to just about every
> other switched jack socket in existance, so the switching action would not
> work with a generic replacement, even though it fitted perfectly.
> (this was either a Laney or Crate guitar combo)


** Seen the exact same thing myself.

Luckily, it was possible to remove the metal parts from the socket and
reverse them.

Seems both Re-An and Cliff can supply mirror image versions - if you want
them.

Gotta be smarter then the "average bear" if repairs are you game .....



.... Phil







== 7 of 8 ==
Date: Mon, Jan 13 2014 6:19 am
From: "William Sommerwerck"


"June Allyson" wrote in message news:bjh556Fr4vhU1@mid.individual.net...

>> I did do my research properly, because I knew I would be subjected to this
>> crap. Did you look at the B215 link I supplied? The B215 is A POWERED
>> SPEAKER, and the 1/4" phone jack is a balanced input. READ WHAT IT SAYS on
>> the Details tab.

** The B215 is a passive speaker -- as stated at the top of the first page
of the link.

http://www.behringer.com/EN/Products/B215.aspx

Says: " * 2 professional speaker connectors (compatible with Neutrik Speakon
connectors) plus �'' jack connectors."

The "details" tab give you a different model -- the B215D which
incorporates a class D amplifier.

The OP made it VERY clear which model he was on about.


Maybe. You will perhaps forgive me for making the not-unreasonable assumption
that a product sheet is supposed to be about one product, not two. (Yes, I saw
the B215D model number on the Details page.)

I'm still wondering why any company would use a stereo connector for a mono
circuit -- but who said the world is rational?





== 8 of 8 ==
Date: Mon, Jan 13 2014 7:11 am
From: "Gareth Magennis"



"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.







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

== 1 of 12 ==
Date: Sun, Jan 12 2014 7:19 pm
From: "DoN. Nichols"


On 2014-01-12, Mike Marlow <mmarlowREMOVE@windstream.net> wrote:
> DaveC wrote:
>>> The reason to use a contactor instead of just an on / off switch is
>>> that the insides of the switch can get full of saw dust and turn on
>>> the saw with the switch in the off position. I've seen this happen!
>>> Regular AC switches are not sealed well enough, but you can buy
>>> sealed switches with lower current ratings which is enough to engage
>>> the contactor.
>>>
>>> Shaun.
>>
>> Best answer yet.
>>
>> 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.
>>
>> Thanks!
>
> It may not get you much mileage with your friend. Despite the previous
> poster's claim to have "seen this", you really have to consider the
> likelihood of such a thing. Wood is an... insulator.

A) Note the newsgroups to which this is cross-posted:

sci.electronics.misc
sci.electronics.repair
rec.crafts.metalworking
rec.woodworking

And while wood may be an insulator, horizontal bandsaws (which I
remember from the earlier articles in this thread, and which I
use) are more commonly used to cut metal. And metal swarf is
certainly conductive.

B) Toggle switches typically have a spring-loaded actuator which
bears on a metal plate which rocks back and forth to bridge
contacts or not bridge them.

Even a buildup of wood sawdust or plastic dust *could* trap the
metal rocker in a position to keep the bridging happening, even
when the toggle is in the "off" position.

> Though he may have
> "seen this", do you think your friend is going to believe it to be a real
> enough possibility for him to consider? There are millions of simple
> switches in shops all over the world - and they work.

And most of those switches are not located near the point of
generation of metal swarf as they are on the typical inexpensive
horizontal bandsaw. The airborne sawdust in a wood-working shop is not
likely to be a problem. However, metal chips dribbled from the blade
(after going almost a full turn around the path of the blade) are a
possibility, depending on the construction of the switch. (And, they
could also conduct from the switch terminals to the chassis of the saw,
if they got under the frame.) Certainly a sealed limit switch (more
commonly found on serious machine tools) would be free of that
particular problem. They are a small MicroSwitch module inside a metal
housing with O-rings to keep out oil as well as chips. They are
operated by a cam, also sealed, or an external plunger -- operating
through a sealed path. (Honeywell is one maker -- and they *are* quite
expensive, but the best thing where swarf will build up.) The wiring
comes in through a fitting which normally has a tapered gasket which
compresses around oil-proof wiring, so there is no path for the chips in
through there either. And yes, the are best used at low voltages and
low currents. I recently re-designed the limit switches in a conversion
of a CNC milling machine, and needed to get switches of the same
physical mounting but which had two separate circuits depending on which
direction they were operated in.)

> It would probably be
> hard to convince your friend their is a real risk here. For good reason...

It is at least a *possible* one. Now, if the power is fed to
this through a wall-mounted disconnect switch, so you could stop the
bandsaw without having to unplug it (which might be difficult to reach
with the saw still running), that would be less of a problem. It would
be nice to have a warning LED near where you would reach to change the
clamping of the workpiece, so you know the saw is still running,
especially of other noisy tools are being run at the same time in the
shop. A horizontal bandsaw is typically fairly quiet, unless it is
cutting relatively thin metal.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
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 ---




== 2 of 12 ==
Date: Sun, Jan 12 2014 7:34 pm
From: "DoN. Nichols"


On 2014-01-12, Ignoramus13867 <ignoramus13867@NOSPAM.13867.invalid> wrote:

[ ... ]

> On 2014-01-12, DaveC <invalid@invalid.net> wrote:
>> A friend (in USA) with a 220v, 1-phase horizontal bandsaw in his home machine
>> shop wants to replace the 1/4 hp motor with 1/2 hp and rewire with an
>> auto-off switch (when the blade cuts through the metal).
>>
>> I always default to using a 3-wire control with contactor, but he asks the
>> logical question: "Why?"

[ ... ]

>> What are the arguments for using a contactor as opposed to a simple on-off
>> switch of equivalent rating?

[ ... ]

> The best argument for using a contactor in a small bandsaw, is that
> you can get proper thermal overloads to protect the motor.
>
> i

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.)

A proper motor starter (of which the contactor is a part)
includes thermal sensors for the current through each winding, and if
any one of the three goes well above the normal full-load running
current (as will happen if one phase dies), it will interrupt the power
to the motor and stop it before the motor is damaged. And it also
protects the windings from burning out when trying to start with one
phase of three missing.

And actually, some starters only measure the current through two
of the three legs, because if one is out, one of the two monitored will
be over-current enough to trip it.

So -- with a single phase 240 VAC motor, the over-current from
loss of a phase would not apply.

But the other reasons for using a motor starter/contactor still
stand.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
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 ---




== 3 of 12 ==
Date: Sun, Jan 12 2014 7:39 pm
From: "DoN. Nichols"


On 2014-01-12, DaveC <invalid@invalid.net> wrote:
>> The best argument for using a contactor in a small bandsaw, is that
>> you can get proper thermal overloads to protect the motor.
>>
>> i
>> cc
>
> Can you get just thermal overloads without a contactor?

Not really. The thermal overloads sense the current in each
winding, and generate heat to soften either a wax or a low temperature
solder to allow a wheel to rotate and a low-current contact to open.
All of the phases have their contacts in series, and in series with the
coil of the contactor. Any one of them opening drops the contactor out
to protect the load.

With single phase, a slow-blow fuse in series with each hot lead
should sufficient, but with three phases, you need to sense any
condition of over-current in any single phase, and to drop everything
once it is sensed. (Of course, if you are running the three-phase motor
from a VFD, that incorporates the functions of the starter (current
sensing and automatic shutdown) in the electronics of the VFD.

Enjoy,
DoN.n

--
Remove oil spill source from e-mail
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 ---




== 4 of 12 ==
Date: Sun, Jan 12 2014 7:43 pm
From: "Mike Marlow"


DoN. Nichols wrote:

> And while wood may be an insulator, horizontal bandsaws (which I
> remember from the earlier articles in this thread, and which I
> use) are more commonly used to cut metal. And metal swarf is
> certainly conductive.
>

You are absolutely correct Don - and thank you for that correction. I got
sidetracked by the one poster who mentioned that he had once seen sawdust
create a short. While I disagree that such is a common or even an
anticipated occurance, I do acknowkedge your clarification - you point is
well taken.


> B) Toggle switches typically have a spring-loaded actuator which
> bears on a metal plate which rocks back and forth to bridge
> contacts or not bridge them.
>
> Even a buildup of wood sawdust or plastic dust *could* trap the
> metal rocker in a position to keep the bridging happening, even
> when the toggle is in the "off" position.

Yes... and the earth could have been flat before centrifigul force changed
all that. My point Don is that yes - things are possible - probable, or
even common in the real world is something different.



>
> It is at least a *possible* one.

I will concede that anything is possible - even my wife deciding... well...
we won't go there... Just because something is possible does not put it in
the realm of probable, practical, or even worth thinking about. I am not
saying that your comments are not worth consideration with that statement,
I'm simply trying to make your statement that it is at least possible as
meaningless in its context as I can.

--

-Mike-
mmarlowREMOVE@windstream.net






== 5 of 12 ==
Date: Sun, Jan 12 2014 8:48 pm
From: Ignoramus28861


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.

i




== 6 of 12 ==
Date: Mon, Jan 13 2014 1:55 am
From: Jasen Betts


On 2014-01-12, Gunner Asch <gunnerasch@gmail.com> wrote:
> On Sat, 11 Jan 2014 23:56:48 -0800, DaveC <invalid@invalid.net> wrote:
>
>>> The best argument for using a contactor in a small bandsaw, is that
>>> you can get proper thermal overloads to protect the motor.
>>>
>>> i
>>> cc
>>
>>Can you get just thermal overloads without a contactor?
>
> Yes..but they are NOT..NOT fuses or circuit breakers. They are
> designed to carry SMALL current loads..often times much smaller than
> the motors they are protecting.
>
> They may read the current..but the internal switches are too small to
> handle repeated ons/offs
>

http://www.sensata.com/klixon/thermostat-precision-7bt2.htm

they describe it as a "thermostat" and rate the contacts at 10A 240V.

probably enough for a 1/2 HP motor.

but if you need the cut-out to switch both terminals that's not going
to suit.

--
For a good time: install ntp

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---




== 7 of 12 ==
Date: Mon, Jan 13 2014 4:11 am
From: "Lloyd E. Sponenburgh"


"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




== 8 of 12 ==
Date: Mon, Jan 13 2014 5:01 am
From: Leif Neland


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?

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






== 9 of 12 ==
Date: Mon, Jan 13 2014 5:04 am
From: David Billington


On 13/01/14 12:11, Lloyd E. Sponenburgh 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.

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.

>
> 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





== 10 of 12 ==
Date: Mon, Jan 13 2014 5:06 am
From: "Lloyd E. Sponenburgh"


David Billington <djb@djbillington.freeserve.co.uk> fired this volley in
news:52d3e44d$0$1398$5b6aafb4@news.zen.co.uk:

> 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.

It's simple, cheap, and easy to rig remote switching and sensors for things
like safety guards. It requires only bell wire and some thoughtful
routing, rather than running live power everywhere a switch is required.

LLoyd




== 11 of 12 ==
Date: Mon, Jan 13 2014 6:28 am
From: "Jim Wilkins"


"David Billington" <djb@djbillington.freeserve.co.uk> wrote in message
news:52d3e44d$0$1398$5b6aafb4@news.zen.co.uk...
>
> 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.

Low voltage control confines the high voltage to the control box and
the motor, so it's less exposed to physical damage. There isn't much
if any benefit if you have only a single short run to the power switch
and the motor draws less than the switch's rating, for the cost of a
24V transformer and a larger control enclosure.

I can't remember ever seeing a contactor and low voltage controls on
consumer power tools although it's pretty much standard for industry.

The difference may be the risk of forklift accidents, since humans
can't crush conduit or puncture sheetmetal.






== 12 of 12 ==
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.


__
"Anyone who thinks Obama is doing a good job
is either stupid or a perpetual societal leech"

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

== 1 of 2 ==
Date: Sun, Jan 12 2014 7:49 pm
From: "Geoffrey S. Mendelson"


vjp2.at@at.BioStrategist.dot.dot.com wrote:
> I could swear the battery I removed was 2023 but when I went to the store
> I pulled out a 2032 which might have gotten confused when I looked for
> 2023. But the 2032 I bought fit into the socket.
>
> The computer in question still has CMOS errors,
> so I'm wondering if I popped the wrong battery in.
> But it fit perfectly in the socket.
>
> THis is a 1995 Gateway (GW2k) P5-75 CMOS battery.
>
> If it was 2023 I lost the 2023. Are they similar enough? Is there any way to
> check which one was used by Gateway? (I had found a completely different one
> online when I searched a few months ago which is why I was susprised which
> one I found)
>

There is a CR2025. Many motherboards of that vintage used them, but probably
just as many used the CR2032. They are close enough in size that a
CR2032 will fit in a socket for a CR2025 that is basically a cup with
tabs to hold the battery in and a large flat spring to contact it.

There is a socket that looks like the letter U where the battery slides
down into it, and that is too close a tolerance for a CR2032 to fit.

At this point, if it works, make a label that says CR2032 on it, and stick
it on the motherboard. :-)

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379





== 2 of 2 ==
Date: Sun, Jan 12 2014 8:39 pm
From: jurb6006@gmail.com


>"There is no CR2023 battery"

It appears I found a typo on the internet. (oh dear lol)

http://www.large-battery.com/cr2023-computer-bios-battery.html





==============================================================================
TOPIC: Yamaha Stagepas 500W
http://groups.google.com/group/sci.electronics.repair/t/ffe9b12e2d51ee46?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 13 2014 2:11 am
From: N_Cook


Had to fudge +/-44V supply before longtail section would bias properly
with mute off. Not in that area , between that and power section proper
a 120V .1A SMD Q with 10V forward across B-E junction. Not an iota of
difference DVM-D cold checking that Q and its good PA brother.
Hopefully enough space between the two tiny PAs for a 120V E-line to go
in there





==============================================================================
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 1 ==
Date: Mon, Jan 13 2014 4:57 am
From: Leif Neland


vjp2.at@at.BioStrategist.dot.dot.com har bragt dette til os:
> 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.
>
How about buying a headset that fits instead of spending money on
numerous adaptors?

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






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