sci.electronics.repair
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Today's topics:

* 1/4" phone jack replacement for Behringer 215 speaker. - 13 messages, 5
authors
http://groups.google.com/group/sci.electronics.repair/t/0fd5e32c8baa1611?hl=en
* Why use a contactor? - 5 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/8a277d142156dff2?hl=en
* CR2023? CR2032 Batteries - 4 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/8e15ac1d36a61277?hl=en
* Batt charged but unplug shuts - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/239916b681296dcf?hl=en
* 3-contact 2.5mm male - 4-contact 3.5 mm female - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/9aa8b3ae778aae08?hl=en
* Favorite Cutters For Snipping DIP Leads? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/30d89f0c2d193f6d?hl=en

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

== 1 of 13 ==
Date: Sun, Jan 12 2014 11:01 am
From: "David Farber"


William Sommerwerck wrote:
> It's amazing Fran Allyson didn't jump all over you.
>
> The 1/4" phone jack is (supposedly) a balanced line-level input. If
> you plug a mono plug into it, the plug's sleeve will short the jack's
> ring to ground. This is normal; there's nothing inherently wrong with
> this. It's one way unbalanced signals can be connected to balanced
> inputs.
> http://www.behringer.com/EN/Products/B215.aspx
>
> I suspect you have a problem that isn't really a problem.

Hi William,

I think if you take an ohmmeter and connect it to a speaker input, and it
measures the lowest reading that it can display, that would be cause for
concern. The only time this happens is when the stereo plug is inserted into
the jack even when the plug isn't connected to anything. How do you perceive
that this isn't a problem?

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







== 2 of 13 ==
Date: Sun, Jan 12 2014 11:04 am
From: "David Farber"


N_Cook wrote:
> On 12/01/2014 01:33, David Farber wrote:
>> 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
>> The Speakon jacks were fastened to the back panel of the cabinet
>> with two screws per jack. On the other end of the screw was a nut.
>> Unfortunately, the nut wasn't anchored to anything so it was futile
>> to try and remove the screw. The circuit board prevented me from
>> inserting any tool in there to hold the nut while I was turning the
>> screw. You can see the results. I replaced the Speakon jacks, no
>> problem. With the help of a Mouser telephone tech to match the original
>> part,
>> I ordered replacement 1/4" phone jacks, manufacturer part number
>> NYS232.
>> http://www.mouser.com/ProductDetail/REAN/NYS232/?qs=%2fha2pyFadujcNYWYyUSyMSHhOqDb3buvV%252b7cmiFFRuQ%3d
>> The owner suggested I replaced both of them as long as I had it
>> apart. The parts arrived and I installed them. I wired everything
>> back in place. Something told me to check the input impedance of the
>> speaker with a multimeter just to make sure it was wired probably.
>> It was a good thing I did. It measured a direct short from the
>> speaker plug input. After searching up and down for a short, I
>> didn't find any until I inserted the phone plug into the jack.
>> That's when an internal contact in the jack switched to a different
>> position and shorted out the plug. Ok, I guess this jack will not
>> work on this pc board. I called Behringer's parts department and had
>> them research the original part. After a day or two of researching,
>> I received a call back from Behringer and ordered the parts. I
>> received the parts today. Excited to finally get the speaker
>> repaired, I removed the Mouser jacks and put in the Behringer jacks,
>> same thing. Direct short across the input terminals. Then I looked
>> inside and noticed there wasn't any difference in the terminal
>> configuration between the Mouser jack and the replacement Behringer
>> jack. I will call Behringer back on Monday to discuss this situation
>> but meanwhile, do any of you know what kind of 1/4" phone jack is
>> supposed to fit on this pc board? Thanks for your reply.
>>
>
> Just a thought, are the outputs in antiphase and just one of them is
> exhibiting this "fault" if you check to chassis ground?

I'm not sure what you mean by outputs. Do you mean the amplifier outputs? I
have not connected it to any amplifier as of yet. I'm just measuring the dc
resistance of the speaker at the input jack.

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






== 3 of 13 ==
Date: Sun, Jan 12 2014 11:41 am
From: "William Sommerwerck"


"David Farber" wrote in message news:lauoqa$lgk$1@dont-email.me...
William Sommerwerck wrote:

> The 1/4" phone jack is (supposedly) a balanced line-level input. If
> you plug a mono plug into it, the plug's sleeve will short the jack's
> ring to ground. This is normal; there's nothing inherently wrong with
> this. It's one way unbalanced signals can be connected to balanced
> inputs.
> http://www.behringer.com/EN/Products/B215.aspx
> I suspect you have a problem that isn't really a problem.

Hi William,

I think if you take an ohmmeter and connect it to a speaker input, and it
measures the lowest reading that it can display, that would be cause for
concern. The only time this happens is when the stereo plug is inserted into
the jack even when the plug isn't connected to anything. How do you perceive
that this isn't a problem?
-------------------------------------------------

As far as I can tell, this isn't a speaker input -- it's a balanced amplifier
input. There is no reason why a mono plug or stereo plug should show a short.

Your description of what's going on seems inconsistent and confused.





== 4 of 13 ==
Date: Sun, Jan 12 2014 2:45 pm
From: "David Farber"


William Sommerwerck wrote:
> "David Farber" wrote in message news:lauoqa$lgk$1@dont-email.me...
> William Sommerwerck wrote:
>
>> The 1/4" phone jack is (supposedly) a balanced line-level input. If
>> you plug a mono plug into it, the plug's sleeve will short the jack's
>> ring to ground. This is normal; there's nothing inherently wrong with
>> this. It's one way unbalanced signals can be connected to balanced
>> inputs.
>> http://www.behringer.com/EN/Products/B215.aspx
>> I suspect you have a problem that isn't really a problem.
>
> Hi William,
>
> I think if you take an ohmmeter and connect it to a speaker input,
> and it measures the lowest reading that it can display, that would be
> cause for concern. The only time this happens is when the stereo plug
> is inserted into the jack even when the plug isn't connected to
> anything. How do you perceive that this isn't a problem?
> -------------------------------------------------
>
> As far as I can tell, this isn't a speaker input -- it's a balanced
> amplifier input. There is no reason why a mono plug or stereo plug
> should show a short.
> Your description of what's going on seems inconsistent and confused.

Hi William,

The are two Speakon and two 1/4" phone jacks wired in parallel that are
situated in the back of the speaker cabinet. It's not a powered speaker. The
inside of the speaker cabinet contains a crossover pc board, a woofer, and a
midrange speaker. When I replaced the damaged 1/4" phone jack and checked
continuity across the pc board input with the speakers disconnected, it
measured open circuit. When I put a monaural phone plug into the jack, I
rechecked the continuity and it was shorted. The monaural phone plug was not
connected to anything on the other end so the short had to becoming from the
jack itself. Does that make sense?

--
David Farber
Los Osos, CA






== 5 of 13 ==
Date: Sun, Jan 12 2014 2:59 pm
From: "Gareth Magennis"




"William Sommerwerck" wrote in message news:laur5g$4vk$1@dont-email.me...

"David Farber" wrote in message news:lauoqa$lgk$1@dont-email.me...
William Sommerwerck wrote:

> The 1/4" phone jack is (supposedly) a balanced line-level input. If
> you plug a mono plug into it, the plug's sleeve will short the jack's
> ring to ground. This is normal; there's nothing inherently wrong with
> this. It's one way unbalanced signals can be connected to balanced
> inputs.
> http://www.behringer.com/EN/Products/B215.aspx
> I suspect you have a problem that isn't really a problem.

Hi William,

I think if you take an ohmmeter and connect it to a speaker input, and it
measures the lowest reading that it can display, that would be cause for
concern. The only time this happens is when the stereo plug is inserted into
the jack even when the plug isn't connected to anything. How do you perceive
that this isn't a problem?
-------------------------------------------------

As far as I can tell, this isn't a speaker input -- it's a balanced
amplifier
input. There is no reason why a mono plug or stereo plug should show a
short.

Your description of what's going on seems inconsistent and confused.





William, why do you keep doing this?

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.

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


David, my usual technique where the original socket cannot easily be
replaced is to simply use a chassis mounted switched jack socket hard wired
to the PCB, if space allows it, after carefully working out what connections
to connect to where.



Gareth.












== 6 of 13 ==
Date: Sun, Jan 12 2014 3:39 pm
From: "David Farber"


Gareth Magennis wrote:
> "William Sommerwerck" wrote in message
> news:laur5g$4vk$1@dont-email.me...
> "David Farber" wrote in message news:lauoqa$lgk$1@dont-email.me...
> William Sommerwerck wrote:
>
>> The 1/4" phone jack is (supposedly) a balanced line-level input. If
>> you plug a mono plug into it, the plug's sleeve will short the jack's
>> ring to ground. This is normal; there's nothing inherently wrong with
>> this. It's one way unbalanced signals can be connected to balanced
>> inputs.
>> http://www.behringer.com/EN/Products/B215.aspx
>> I suspect you have a problem that isn't really a problem.
>
> Hi William,
>
> I think if you take an ohmmeter and connect it to a speaker input,
> and it measures the lowest reading that it can display, that would be
> cause for concern. The only time this happens is when the stereo plug
> is inserted into the jack even when the plug isn't connected to
> anything. How do you perceive that this isn't a problem?
> -------------------------------------------------
>
> As far as I can tell, this isn't a speaker input -- it's a balanced
> amplifier
> input. There is no reason why a mono plug or stereo plug should show a
> short.
>
> Your description of what's going on seems inconsistent and confused.
>
>
>
>
>
> William, why do you keep doing this?
>
> 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.
>
> Clearly there is a problem with the replacement jack socket that
> seems to provide a short with a mono jack plug inserted in it.
>
>
> David, my usual technique where the original socket cannot easily be
> replaced is to simply use a chassis mounted switched jack socket hard
> wired to the PCB, if space allows it, after carefully working out
> what connections to connect to where.
>
>
>
> Gareth.

Hi Gareth,

There is lots of space to drill a new hole and mount another jack. Then it
doesn't have to fit the pc board directly. Why would it have to be a
switched jack? What would it be switching?

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






== 7 of 13 ==
Date: Sun, Jan 12 2014 4:36 pm
From: "Gareth Magennis"




"David Farber" wrote in message news:lav951$3u4$1@dont-email.me...

Gareth Magennis wrote:
> "William Sommerwerck" wrote in message
> news:laur5g$4vk$1@dont-email.me...
> "David Farber" wrote in message news:lauoqa$lgk$1@dont-email.me...
> William Sommerwerck wrote:
>
>> The 1/4" phone jack is (supposedly) a balanced line-level input. If
>> you plug a mono plug into it, the plug's sleeve will short the jack's
>> ring to ground. This is normal; there's nothing inherently wrong with
>> this. It's one way unbalanced signals can be connected to balanced
>> inputs.
>> http://www.behringer.com/EN/Products/B215.aspx
>> I suspect you have a problem that isn't really a problem.
>
> Hi William,
>
> I think if you take an ohmmeter and connect it to a speaker input,
> and it measures the lowest reading that it can display, that would be
> cause for concern. The only time this happens is when the stereo plug
> is inserted into the jack even when the plug isn't connected to
> anything. How do you perceive that this isn't a problem?
> -------------------------------------------------
>
> As far as I can tell, this isn't a speaker input -- it's a balanced
> amplifier
> input. There is no reason why a mono plug or stereo plug should show a
> short.
>
> Your description of what's going on seems inconsistent and confused.
>
>
>
>
>
> William, why do you keep doing this?
>
> 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.
>
> Clearly there is a problem with the replacement jack socket that
> seems to provide a short with a mono jack plug inserted in it.
>
>
> David, my usual technique where the original socket cannot easily be
> replaced is to simply use a chassis mounted switched jack socket hard
> wired to the PCB, if space allows it, after carefully working out
> what connections to connect to where.
>
>
>
> Gareth.

Hi Gareth,

There is lots of space to drill a new hole and mount another jack. Then it
doesn't have to fit the pc board directly. Why would it have to be a
switched jack? What would it be switching?

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


A switched jack will just cover all possibilities. You can use the
switching or ignore it, the cost is pretty much the same.

I can't see how a switched jack might be used in this unit, but nor can I
see how inserting a mono jack plug into the replacement socket can cause a
short, so something in the wiring is amiss.

You might not need to drill a new hole, you may be able to fit the chassis
mounting socket in the original hole, and just run wires from it to the PCB.
Hot melt glue or silicone sealant will secure and insulate it.


Gareth.






== 8 of 13 ==
Date: Sun, Jan 12 2014 4:53 pm
From: dave


On 01/11/2014 05:33 PM, David Farber wrote:
> 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
> The Speakon jacks were fastened to the back panel of the cabinet with two
> screws per jack. On the other end of the screw was a nut. Unfortunately, the
> nut wasn't anchored to anything so it was futile to try and remove the
> screw. The circuit board prevented me from inserting any tool in there to
> hold the nut while I was turning the screw. You can see the results. I
> replaced the Speakon jacks, no problem.
>
> With the help of a Mouser telephone tech to match the original part, I
> ordered replacement 1/4" phone jacks, manufacturer part number NYS232.
> http://www.mouser.com/ProductDetail/REAN/NYS232/?qs=%2fha2pyFadujcNYWYyUSyMSHhOqDb3buvV%252b7cmiFFRuQ%3d
> The owner suggested I replaced both of them as long as I had it apart. The
> parts arrived and I installed them. I wired everything back in place.
> Something told me to check the input impedance of the speaker with a
> multimeter just to make sure it was wired probably. It was a good thing I
> did. It measured a direct short from the speaker plug input. After searching
> up and down for a short, I didn't find any until I inserted the phone plug
> into the jack. That's when an internal contact in the jack switched to a
> different position and shorted out the plug. Ok, I guess this jack will not
> work on this pc board. I called Behringer's parts department and had them
> research the original part. After a day or two of researching, I received a
> call back from Behringer and ordered the parts. I received the parts today.
> Excited to finally get the speaker repaired, I removed the Mouser jacks and
> put in the Behringer jacks, same thing. Direct short across the input
> terminals. Then I looked inside and noticed there wasn't any difference in
> the terminal configuration between the Mouser jack and the replacement
> Behringer jack. I will call Behringer back on Monday to discuss this
> situation but meanwhile, do any of you know what kind of 1/4" phone jack is
> supposed to fit on this pc board?
>
> Thanks for your reply.
>
Tell Del Hopkins I said "hi". Thanks.




== 9 of 13 ==
Date: Sun, Jan 12 2014 5:34 pm
From: "Phil Allison"



"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






== 10 of 13 ==
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.





== 11 of 13 ==
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.





== 12 of 13 ==
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







== 13 of 13 ==
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









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

== 1 of 5 ==
Date: Sun, Jan 12 2014 12:08 pm
From: Gunner Asch


On Sun, 12 Jan 2014 13:56:33 -0500, clare@snyder.on.ca wrote:

>On Sat, 11 Jan 2014 22:45:56 -0800, John Robertson <spam@flippers.com>
>wrote:
>
>>On 01/11/2014 8:41 PM, Mike Marlow 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. 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. It would probably be
>>> hard to convince your friend their is a real risk here. For good reason...
>>>
>>
>>Wood may be an insulater but carbon certainly isn't. I suspect what the
>>provious poster was talking about was burnt bits of sawdust being
>>conductive. They would be burnt by the sparks present when the switch
>>was opened...leading to a potentially hazardous situation!
>>
>>John :-#(#
> Or dust physically jamming the motion of the switch contacts - - -

Indeed.

I do service work on the side for a So Cal tool buyer/seller and the
number of switches Ive pulled out of wood working machinery jammed
solid with sawdust is huge. Even so called "sealed" switches.

Gunner

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

---
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== 2 of 5 ==
Date: Sun, Jan 12 2014 12:12 pm
From: Gunner Asch


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


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

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== 3 of 5 ==
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
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--- Black Holes are where God is dividing by zero ---




== 4 of 5 ==
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.

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




== 5 of 5 ==
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

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Email: <BPdnicholsBP@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---





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

== 1 of 4 ==
Date: Sun, Jan 12 2014 5:51 pm
From: vjp2.at@at.BioStrategist.dot.dot.com


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)



- = -
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]








== 2 of 4 ==
Date: Sun, Jan 12 2014 6:02 pm
From: jurb6006@gmail.com


According to the internet they are pretty much the same. An old PC like that might need some manual configuration. I'd pull out pretty much everything and load setup or default values and see what happens. then add stuff one at a time, probably starting with the harddrive.




== 3 of 4 ==
Date: Sun, Jan 12 2014 6:32 pm
From: Jeff Liebermann


On Mon, 13 Jan 2014 01:51:36 +0000 (UTC),
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)

A CR2032 is 20 mm diameter, 3.2 mm thick, 225ma-hr
A CR2025 is 20 mm diameter, 2.5 mm thick, 165ma-hr
There is no CR2023 battery.
Either will fit in a 20 mm dia battery holder.

The only real difference is that the 2025 is thinner and may not make
as solid a connection as the thicker CR2032. You can bend the top +
terminal on the battery holder to compensate. However, I'm fairly
sure your ancient Gateway uses a CR2032 battery and that you bought
and installed the correct battery.

Why it doesn't work is unknown.
Did you install it upside-down? The + goes on top.

--
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




== 4 of 4 ==
Date: Sun, Jan 12 2014 6:56 pm
From: "William Sommerwerck"


I think you misread the number. There is no CR2023, but there is a CR2025.

The difference among these cells is their thickness, which translates into a
difference in capacity. There is nothing wrong with using a higher-capacity
cell than required, unless (as someone else pointed out), it doesn't make
proper contact.

It's a good idea to keep a separate list of the CMOS settings, "just in case"
you have to re-enter values appropriate to your computer. In principle, any
computer should boot with the default settings.






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

== 1 of 1 ==
Date: Sun, Jan 12 2014 6:02 pm
From: vjp2.at@at.BioStrategist.dot.dot.com


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.

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 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: 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 2 ==
Date: Sun, Jan 12 2014 6:05 pm
From: vjp2.at@at.BioStrategist.dot.dot.com


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]








== 2 of 2 ==
Date: Sun, Jan 12 2014 6:34 pm
From: Jeff Liebermann


On Mon, 13 Jan 2014 02:05:38 +0000 (UTC),
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.

Slightly wrong. A 3 contact 3.5mm plug can be used for earphones
only, but if you want a microphone, you'll need the 4th connection
(nearest the plug).
>
>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?

This should help:
<http://www.ediy.co.nz/use-ipod-touch-iphone-with-skype-xidc55676.html>
--
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: Favorite Cutters For Snipping DIP Leads?
http://groups.google.com/group/sci.electronics.repair/t/30d89f0c2d193f6d?hl=en
==============================================================================

== 1 of 1 ==
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.




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