sci.electronics.repair@googlegroups.com

Today's topics:

* TO INFECT YOUR COMPUTER IN A SECOND - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/0bb447a4b4f95df6?hl=en
* Danger of running hot receiver (Kyocera)? - 6 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/2eeb7d68559500c5?hl=en
* Where to get schematic of Funai TV, Model FT1371? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/f75b6f935b5d3675?hl=en
* How do I check the output of an amp with a scope? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/6b586764171b3ca8?hl=en
* Rectifier wiring - 13 messages, 11 authors
http://groups.google.com/group/sci.electronics.repair/t/b087d99e9ce594b1?hl=en
* continuous action solder sucker - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/1447a02166d89d01?hl=en
* So, who's the king of finding data sheets ... ? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/4e444c319ac55fa0?hl=en

==============================================================================
TOPIC: TO INFECT YOUR COMPUTER IN A SECOND
http://groups.google.com/group/sci.electronics.repair/t/0bb447a4b4f95df6?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Jul 1 2010 10:47 am
From: Meat Plow

On Thu, 01 Jul 2010 08:00:40 -0700, Tiresh kumar K.C ǝʇoɹʍ:

> DEAR ALL ,
>
>
> VISIT:
> Click here
>
> http://infectmypc.blogspot.com
>
>
> AND TO INFECT YOUR COMPUTER IN A SECOND :
>
>
> TO KNOW YOU'VE BEEN SCREWED ROYAL
>
>
>
> -NEW MALWARE
>
> -SUCCESS IN INFECTION
>
> -THOUGHT YOU WERE

==============================================================================
TOPIC: Danger of running hot receiver (Kyocera)?
http://groups.google.com/group/sci.electronics.repair/t/2eeb7d68559500c5?hl=en
==============================================================================

== 1 of 6 ==
Date: Thurs, Jul 1 2010 2:16 pm
From: "Trevor Wilson"

"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:i0e4fs$apf$1@reader1.panix.com...
> David Nebenzahl <nobody@but.us.chickens> wrote:
>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
>> "smells like something's burning". Don't have more specific information
>> than that; I'm assuming no magic smoke is visible. I'm advising them
>> that perhaps something (dust, etc.) is in the heat sink that's getting
>> heated and smelling. Apparently the output stages (MOSFET) of these
>> beasts tend to run on the hot side.
>
> weird heatsink in that thing:
>
> http://www.audiokarma.org/forums/showthread.php?t=246095

**Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the fluid
has leaked, there can be problems. A quick way to test is to power up and
ensure that heat travels rapidly (less than 10 seconds) from the hot devices
to the other end of the heat pipe. If it doesn't then it is possible that
the fluid is gone from inside the pipe.

--
Trevor Wilson
www.rageaudio.com.au

== 2 of 6 ==
Date: Thurs, Jul 1 2010 2:24 pm
From: David Nebenzahl

On 7/1/2010 2:16 PM Trevor Wilson spake thus:

> "Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
> news:i0e4fs$apf$1@reader1.panix.com...
>
>> David Nebenzahl <nobody@but.us.chickens> wrote:
>>
>>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
>>> "smells like something's burning". Don't have more specific information
>>> than that; I'm assuming no magic smoke is visible. I'm advising them
>>> that perhaps something (dust, etc.) is in the heat sink that's getting
>>> heated and smelling. Apparently the output stages (MOSFET) of these
>>> beasts tend to run on the hot side.
>>
>> weird heatsink in that thing:
>>
>> http://www.audiokarma.org/forums/showthread.php?t=246095
>
> **Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the fluid
> has leaked, there can be problems. A quick way to test is to power up and
> ensure that heat travels rapidly (less than 10 seconds) from the hot devices
> to the other end of the heat pipe. If it doesn't then it is possible that
> the fluid is gone from inside the pipe.

Having been inside this unit before, I'm fairly certain the heat pipe is
intact.

Any idea what the fluid is?

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

== 3 of 6 ==
Date: Thurs, Jul 1 2010 2:56 pm
From: "Trevor Wilson"

"David Nebenzahl" <nobody@but.us.chickens> wrote in message
news:4c2d0650$0$3736$822641b3@news.adtechcomputers.com...
> On 7/1/2010 2:16 PM Trevor Wilson spake thus:
>
>> "Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
>> news:i0e4fs$apf$1@reader1.panix.com...
> >
>>> David Nebenzahl <nobody@but.us.chickens> wrote:
> >>
>>>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
>>>> "smells like something's burning". Don't have more specific information
>>>> than that; I'm assuming no magic smoke is visible. I'm advising them
>>>> that perhaps something (dust, etc.) is in the heat sink that's getting
>>>> heated and smelling. Apparently the output stages (MOSFET) of these
>>>> beasts tend to run on the hot side.
>>>
>>> weird heatsink in that thing:
>>>
>>> http://www.audiokarma.org/forums/showthread.php?t=246095
>>
>> **Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the
>> fluid has leaked, there can be problems. A quick way to test is to power
>> up and ensure that heat travels rapidly (less than 10 seconds) from the
>> hot devices to the other end of the heat pipe. If it doesn't then it is
>> possible that the fluid is gone from inside the pipe.
>
> Having been inside this unit before, I'm fairly certain the heat pipe is
> intact.

**You need to measure to be certain.

>
> Any idea what the fluid is?

**Not really. Some kind of refrigerant. It could be FreonT, ammonia, alcohol
or a number of others.

--
Trevor Wilson
www.rageaudio.com.au

== 4 of 6 ==
Date: Thurs, Jul 1 2010 3:20 pm
From: Cydrome Leader

Trevor Wilson <trevor@rageaudio.com.au> wrote:
>
> "David Nebenzahl" <nobody@but.us.chickens> wrote in message
> news:4c2d0650$0$3736$822641b3@news.adtechcomputers.com...
>> On 7/1/2010 2:16 PM Trevor Wilson spake thus:
>>
>>> "Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
>>> news:i0e4fs$apf$1@reader1.panix.com...
>> >
>>>> David Nebenzahl <nobody@but.us.chickens> wrote:
>> >>
>>>>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
>>>>> "smells like something's burning". Don't have more specific information
>>>>> than that; I'm assuming no magic smoke is visible. I'm advising them
>>>>> that perhaps something (dust, etc.) is in the heat sink that's getting
>>>>> heated and smelling. Apparently the output stages (MOSFET) of these
>>>>> beasts tend to run on the hot side.
>>>>
>>>> weird heatsink in that thing:
>>>>
>>>> http://www.audiokarma.org/forums/showthread.php?t=246095
>>>
>>> **Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the
>>> fluid has leaked, there can be problems. A quick way to test is to power
>>> up and ensure that heat travels rapidly (less than 10 seconds) from the
>>> hot devices to the other end of the heat pipe. If it doesn't then it is
>>> possible that the fluid is gone from inside the pipe.
>>
>> Having been inside this unit before, I'm fairly certain the heat pipe is
>> intact.
>
> **You need to measure to be certain.
>
>>
>> Any idea what the fluid is?
>
> **Not really. Some kind of refrigerant. It could be FreonT, ammonia, alcohol
> or a number of others.

I got curious and dug up a sample of a heat pipe (Noren Products
http://www.norenproducts.com ) from a trade show, and it seems they can
even be filled with distilled water depending on the use.

It's still interesting to me that anybody bothered to use these in
amplifiers, products where nobody cares about size and complains about it
being made too sturdy and too heavy.

I have an ATI amp where it's not clear if the heatsinks or tranformer
weigh more.

== 5 of 6 ==
Date: Thurs, Jul 1 2010 3:28 pm
From: Robert Macy

On Jul 1, 2:24 pm, David Nebenzahl <nob...@but.us.chickens> wrote:
> On 7/1/2010 2:16 PM Trevor Wilson spake thus:
>
>
>
>
>
>
>
> > "Cydrome Leader" <prese...@MUNGEpanix.com> wrote in message
> >news:i0e4fs$apf$1@reader1.panix.com...
>
> >> David Nebenzahl <nob...@but.us.chickens> wrote:
>
> >>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
> >>> "smells like something's burning". Don't have more specific information
> >>> than that;  I'm assuming no magic smoke is visible. I'm advising them
> >>> that perhaps something (dust, etc.) is in the heat sink that's getting
> >>> heated and smelling. Apparently the output stages (MOSFET) of these
> >>> beasts tend to run on the hot side.
>
> >> weird heatsink in that thing:
>
> >>http://www.audiokarma.org/forums/showthread.php?t=246095
>
> > **Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the fluid
> > has leaked, there can be problems. A quick way to test is to power up and
> > ensure that heat travels rapidly (less than 10 seconds) from the hot devices
> > to the other end of the heat pipe. If it doesn't then it is possible that
> > the fluid is gone from inside the pipe.
>
> Having been inside this unit before, I'm fairly certain the heat pipe is
> intact.
>
> Any idea what the fluid is?
>
> --
> The fashion in killing has an insouciant, flirty style this spring,
> with the flaunting of well-defined muscle, wrapped in flags.
>
> - Comment from an article on Antiwar.com (http://antiwar.com)

At a show a heat pipe/heat sink company took a straight normal looking
tube at room temperature and plunging it into ice water transferred
ice water temp to your hand NOW! The speed of the heat flow was
impressive. a simple copper pipe was no where near as fast.

Old issues of ?? Electronics Design?? described the heat pipe and its
operation in great detail. Should be at Wiki, or someplace, too.

I think this is the right firm for heat pipes. I munged his email
address a bit.

Amir Tahsini, Regional Sales Manager
Radian Heatsinks an Intricast Div.
2160 Walsh Avenue
Santa Clara, CA 95050
Phone: 408-988-6200 ext. 224
Fax: 408-988-0683
Email: atahsini
@?radianheatsinks .?com

http://www.radianheatsinks.com

== 6 of 6 ==
Date: Thurs, Jul 1 2010 4:03 pm
From: Meat Plow

On Thu, 01 Jul 2010 22:20:16 +0000, Cydrome Leader ǝʇoɹʍ:

> Trevor Wilson <trevor@rageaudio.com.au> wrote:
>>
>> "David Nebenzahl" <nobody@but.us.chickens> wrote in message
>> news:4c2d0650$0$3736$822641b3@news.adtechcomputers.com...
>>> On 7/1/2010 2:16 PM Trevor Wilson spake thus:
>>>
>>>> "Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
>>>> news:i0e4fs$apf$1@reader1.panix.com...
>>> >
>>>>> David Nebenzahl <nobody@but.us.chickens> wrote:
>>> >>
>>>>>> Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they
>>>>>> say "smells like something's burning". Don't have more specific
>>>>>> information than that; I'm assuming no magic smoke is visible. I'm
>>>>>> advising them that perhaps something (dust, etc.) is in the heat
>>>>>> sink that's getting heated and smelling. Apparently the output
>>>>>> stages (MOSFET) of these beasts tend to run on the hot side.
>>>>>
>>>>> weird heatsink in that thing:
>>>>>
>>>>> http://www.audiokarma.org/forums/showthread.php?t=246095
>>>>
>>>> **Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the
>>>> fluid has leaked, there can be problems. A quick way to test is to
>>>> power up and ensure that heat travels rapidly (less than 10 seconds)
>>>> from the hot devices to the other end of the heat pipe. If it doesn't
>>>> then it is possible that the fluid is gone from inside the pipe.
>>>
>>> Having been inside this unit before, I'm fairly certain the heat pipe
>>> is intact.
>>
>> **You need to measure to be certain.
>>
>>
>>> Any idea what the fluid is?
>>
>> **Not really. Some kind of refrigerant. It could be FreonT, ammonia,
>> alcohol or a number of others.
>
> I got curious and dug up a sample of a heat pipe (Noren Products
> http://www.norenproducts.com ) from a trade show, and it seems they can
> even be filled with distilled water depending on the use.
>
> It's still interesting to me that anybody bothered to use these in
> amplifiers, products where nobody cares about size and complains about
> it being made too sturdy and too heavy.
>
> I have an ATI amp where it's not clear if the heatsinks or tranformer
> weigh more.

The whole heatpipe/heat sink/mosfet mount block assembly on my SCS
350x350 WRMS rackmount amp probably weighs 2 pounds minus the 12 fets.
The actual heat sink looks like a round bristled aluminum brush through
which an infinitely speed controlled fan blows through from back to
front. SCS is not in business now, hasn't been for a long time but I
really like this amp. Low THD for a pro audio amp easily usable for a big
home system. Makes no noise unless you're pushing it then the noise
doesn't really matter.

==============================================================================
TOPIC: Where to get schematic of Funai TV, Model FT1371?
http://groups.google.com/group/sci.electronics.repair/t/f75b6f935b5d3675?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Jul 1 2010 3:09 pm
From: Robert Macy

On Jul 1, 8:39 am, <jet...@bc-mung-supernet.com> wrote:
> In article <cf0e27fd-cd11-4476-bf7a-
> d07eb13a0...@y11g2000yqm.googlegroups.com>, m...@california.com says...> Anybody got one lying around?
>
> > Or at least covering the PCB on the back of the CRT neck?
>
>    www.funai-corp.com
>
> --- news://freenews.netfront.net/ - complaints: n...@netfront.net ---

Thank you for that URL!

I didn't even think to try there, but sadly there's only a User's
Manual, which I have a copy of.

==============================================================================
TOPIC: How do I check the output of an amp with a scope?
http://groups.google.com/group/sci.electronics.repair/t/6b586764171b3ca8?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Jul 1 2010 4:09 pm
From: Robert Macy

On Jun 30, 1:38 pm, "fynnas...@yahoo.com" <fynnas...@yahoo.com> wrote:
> On Jun 30, 8:15 pm, whit3rd <whit...@gmail.com> wrote:
>
> > On Jun 30, 11:38 am, "fynnas...@yahoo.com" <fynnas...@yahoo.com>
> > wrote:
>
> > >       I have built a mic amp and wanted to check the wave form on a
> > > scope but when I connect the probes to the o/p of the amp the power
> > > supply trips (The Mic operates on 9 volt single rail.)
>
> > Is one of your scope probes a GROUND connection?  Couple to the
> > microphone amp output through a coupling transformer, see if that
> > helps.
>
> > Which power supply trips, the scope, or the microphone amp?  What
> > are the specifications of that power supply?
>
> Thanks
>  no the ground connection of the scope is connected directly to the
> Amp
> Its the power supply connected to the amp that trips or reads about 4
> volts instead of 9v
> The current of the PSU was set to 1 Ampere.
> Please, generally, how do you check the responds of an audio Amp on
> the scope? I mean how the probes are connected.

need a good explanation of what is in that power supply

or, how about float the power supply, even better, use a battery.

then you should be able to connect your scope ground anywhere on the
circuit. just make sure your mike, amplifier, and power supply are all
floating.

Usually one connects the ground of the scope to the system's reference
point, also called ground, and connects the input of scope to the
output of the amplifier. If the output of the amplifier is an 'H'
drive, you will need two input probes, one for each output leg.

If you get the amplifier up and running there's a way to use your
sound card in your PC to explore what is happening at different
frequencies and what the bandwidth of your system is.

==============================================================================
TOPIC: Rectifier wiring
http://groups.google.com/group/sci.electronics.repair/t/b087d99e9ce594b1?hl=en
==============================================================================

== 1 of 13 ==
Date: Thurs, Jul 1 2010 4:16 pm
From: Ignoramus14602

I have this rectifier: GPBC 50A

http://tinyurl.com/25fmjfu

It has four terminals, but they are not marked. The datasheet is pretty
sparse, too. Which of them are AC and which are DC?

i

== 2 of 13 ==
Date: Thurs, Jul 1 2010 4:27 pm
From: Ned Simmons

On Thu, 01 Jul 2010 18:16:14 -0500, Ignoramus14602
<ignoramus14602@NOSPAM.14602.invalid> wrote:

>I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
>It has four terminals, but they are not marked. The datasheet is pretty
>sparse, too. Which of them are AC and which are DC?
>

You can figger it out in a minute or two with your DMM.

--
Ned Simmons

== 3 of 13 ==
Date: Thurs, Jul 1 2010 4:35 pm
From: Winston

On 7/1/2010 4:16 PM, Ignoramus14602 wrote:
> I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
> It has four terminals, but they are not marked. The datasheet is pretty
> sparse, too. Which of them are AC and which are DC?

Put your multimeter in 'junction test' continuity mode.
(Normally indicated by a diode symbol.)
Test across every terminal combination of both polarities
until you locate the diodes as they conduct in forward
direction (Red + to Anode, Black - to Cathode) and as
they block in reverse direction (Red + to Cathode, Black -
to Anode). Write down each reading on a large sketch
of the part and all will be revealed.

It'll prolly end up looking a lot like:
http://www.fairchildsemi.com/ds/GB/GBPC12005.pdf

--Winston

== 4 of 13 ==
Date: Thurs, Jul 1 2010 4:41 pm
From: Spehro Pefhany

On Thu, 01 Jul 2010 18:16:14 -0500, the renowned Ignoramus14602
<ignoramus14602@NOSPAM.14602.invalid> wrote:

>I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
>It has four terminals, but they are not marked. The datasheet is pretty
>sparse, too. Which of them are AC and which are DC?
>
>i

The one on the chamfered corner that's at 90� to the rest is the +,
the one _diaagonally_ opposite is the -, and the other two are the AC
input terminals.

Check it on 12VDC with a small light bulb in series to be sure. You
should measure 11VDC or so out with the + terminal as I said,
regardless of the polarity of the input (and, of course, the series
light should never light up (!)).

As Ned said, this is easily figured out with a DMM that has a diode
check range, but compare it with a regular diode to be sure of the
polarity. Most digital DMMs have the red lead source positive voltage,
and most analog VOMs are the opposite.

http://www.repairfaq.org/sam/semitest.htm#sttdj

Obviously if you get it wrong you'll probably kill the bridge or cause
the capacitor to vent its lifeblood.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

== 5 of 13 ==
Date: Thurs, Jul 1 2010 4:40 pm
From: BQ340

On 7/1/2010 7:16 PM, Ignoramus14602 wrote:
> I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
> It has four terminals, but they are not marked. The datasheet is pretty
> sparse, too. Which of them are AC and which are DC?
>
> i

Usually the clipped corner (or terminal that is not oriented the same as
the other 3) is the positive & the diagonal opposite is negative. The
other 2 are the AC.

<http://www.softwareforeducation.com/electronics/notes/AS/Diode/bridge-rectifier.jpg>

MikeB

== 6 of 13 ==
Date: Thurs, Jul 1 2010 5:17 pm
From: news@jecarter.us

On Thu, 01 Jul 2010 18:16:14 -0500, Ignoramus14602
<ignoramus14602@NOSPAM.14602.invalid> wrote:

>I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
>It has four terminals, but they are not marked. The datasheet is pretty
>sparse, too. Which of them are AC and which are DC?
>
>i

The GBPC case seems to use the angled corner as the + indicator. See
this datasheet: http://www.vishay.com/docs/88612/gbpc12.pdf

John

== 7 of 13 ==
Date: Thurs, Jul 1 2010 5:20 pm
From: "Lloyd E. Sponenburgh"

Ignoramus14602 <ignoramus14602@NOSPAM.14602.invalid> fired this volley in
news:7NSdneQgVuYjvLDRnZ2dnUVZ_radnZ2d@giganews.com:

> http://tinyurl.com/25fmjfu

They ARE marked, Iggy. The corner miter usually denotes the + output lead.

LLoyd

== 8 of 13 ==
Date: Thurs, Jul 1 2010 5:53 pm
From: "Pete C."

Ignoramus14602 wrote:
>
> I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
> It has four terminals, but they are not marked. The datasheet is pretty
> sparse, too. Which of them are AC and which are DC?
>
> i

Have you looked on the *top* of the case?

== 9 of 13 ==
Date: Thurs, Jul 1 2010 6:11 pm
From: "Karl Townsend"

...
> Obviously if you get it wrong you'll probably kill the bridge or cause
> the capacitor to vent its lifeblood.
`...

You guys are taking all the excitement out of Iggy's life. Just hook it up,
the smoke will come out if its wrong, then do something else. Like the time
I tried a start cap in the run cap position on my three phase converter.
Now, I know the difference.

Karl

== 10 of 13 ==
Date: Thurs, Jul 1 2010 6:49 pm
From: Ignoramus14602

On 2010-07-01, Ignoramus14602 <ignoramus14602@NOSPAM.14602.invalid> wrote:
> I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
> It has four terminals, but they are not marked. The datasheet is pretty
> sparse, too. Which of them are AC and which are DC?

I figured it out. Thanks to all. The power supply is now working
nicely.

i

== 11 of 13 ==
Date: Thurs, Jul 1 2010 6:50 pm
From: Ignoramus14602

On 2010-07-02, Karl Townsend <karltownsend.NOT@embarqmail.com> wrote:
> ...
>> Obviously if you get it wrong you'll probably kill the bridge or cause
>> the capacitor to vent its lifeblood.
> `...
>
> You guys are taking all the excitement out of Iggy's life. Just hook it up,
> the smoke will come out if its wrong, then do something else. Like the time
> I tried a start cap in the run cap position on my three phase converter.
> Now, I know the difference.

I know the fun feeling. In about 0.1 seconds after a loud BANG I know
that something went very wrong.

i

== 12 of 13 ==
Date: Thurs, Jul 1 2010 9:02 pm
From: clare@snyder.on.ca

On Thu, 01 Jul 2010 18:16:14 -0500, Ignoramus14602
<ignoramus14602@NOSPAM.14602.invalid> wrote:

>I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
>It has four terminals, but they are not marked. The datasheet is pretty
>sparse, too. Which of them are AC and which are DC?
>
Use your ohm meter to check the polarity of the 4 diodes. The AC
goes to the points where the positive and negative diodes join.
You get DC+ where the 2 positive diodes joinn, and DC- whre the
negative diodes join. GENERALLY the cut off corner, if present, is one
of the DC terminals.

== 13 of 13 ==
Date: Thurs, Jul 1 2010 10:10 pm
From: "DoN. Nichols"

On 2010-07-01, Ignoramus14602 <ignoramus14602@NOSPAM.14602.invalid> wrote:
> I have this rectifier: GPBC 50A
>
> http://tinyurl.com/25fmjfu
>
> It has four terminals, but they are not marked. The datasheet is pretty
> sparse, too. Which of them are AC and which are DC?

The terminal nearest the corner which is cut off is the positive
output. (Also, it is at right angles to the other three) The diagonally
opposite one is the negative. The other two are AC input.

You can verify this with a multimeter in the ohms or the
diode-check positions. Positive probe on the negative terminal will
show conduction to the other two adjacent terminals. Negative probe on
the Positive terminal will show conduction to the other two adjacent
terminals.

The diodes are arranged pretty much like the schematic symbol
for a bridge rectifier, and surround the center mounting hole as shown
here. Always positive and negative are opposite corners, and the AC
inputs are the other two corners. Something will mark the positive
terminal as different -- here the cut corner and the blade being at
right angles to the rest of the blades. Sometimes there is a red dot by
the positive terminal, black near the negative (except on black potting
epoxy), and yellow on the two AC inputs.

I guess that they did not spell this out on the data sheet
because it is so common a construction -- and has been for at least
forty years or so. Or -- it might be spelled out somewhere else in the
Comchip products manual -- and you only have two pages out of that
manual.

Enjoy,
DoN.

--
Email: <dnichols@d-and-d.com> | 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 ---

==============================================================================
TOPIC: continuous action solder sucker
http://groups.google.com/group/sci.electronics.repair/t/1447a02166d89d01?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Jul 1 2010 5:04 pm
From: Jim Yanik

zekfrivo@zekfrivolous.com (GregS) wrote in
news:i0iabg$r25$3@usenet01.srv.cis.pitt.edu:

> In article
> <732fbe89-97bd-499f-ad18-99066ece2603@d37g2000yqm.googlegroups.com>,
> rush14 <rush14@columbus.rr.com> wrote:
>>On Jun 29, 11:05=A0am, rush14 <rus...@columbus.rr.com> wrote:
>>> I'm attempting to fabricate a continuous action solder sucker along
>>> the lines of those used at work
>>>
>>> when repairing circuit boards. =A0They were fast, clean, easy to use
>>> and prevented damage to the circuit boards from excessive prolonged
>>> heat.
>>>
>>> Unfortunately I'm now retired and the factory work has all been
>>> outsourced overseas. =A0There's nobody left now from work who would
>>> know about this.
>>>
>>> As I recall they consisted of a vacuum source (unknown to me), a
>>> flexible hose connected to a small cylinder with a tuft of steel
>>> wool inside to trap solder and a =A0teflon sucking tip at the other
>>> end of the cylinder.
>>>
>>> Apparently there is more to vacuum technology than I imagined
>>> because all my attempts have so far failed miserably. =A0When I
>>> adapt a short (~3 foot) flexible hose to my vacuum source the
>>> suction at the end of the hose is almost non-existent.
>>>
>>> My first attempt was using the air intake of a 12V automotive tire
>>> inflator, an idea I got from extensive Google searching, although
>>> not intended for that purpose. There seemed to be plenty of suction
>>> at the air intake itself but almost no suction at the end of the
>>> flexible hose.
>>>
>>> I then decided to go to extremes and adapted the hose to the vacuum
>>> port of a powerful shop vac. =A0I actually expected the hose to
>>> collapse from excessive vacuum but instead there was again almost no
>>> suction at the end of the hose. =A0I then added a secondary intake
>>> port to alleviate what I thought might be excessive load on the shop
>>> vac then tried using the shop vac exhaust port to create a vacuum.
>>> =A0Neither attempt worked.
>>>
>>> I would normally give up but I know the theory behind it works from
>>> my experience at the factory. =A0I'm apparently ignorant in the
>>> physics of vacuum.
>>>
>>> I'm also familiar with other desoldering tools including plunger and
>>> squeeze bulb solder suckers, solder wick and built in suckers on
>>> soldering irons. =A0I've found them all lacking in one way or
>>> another compared to the gizmo I'm trying to imitate from the
>>> factory.
>>>
>>> Any ideas from you guys about the error of my ways will be greatly
>>> appreciated.
>>>
>>> Thanks a bunch,
>>> Rush
>>
>>I appreciate the 5 responses I received and all your advice is well
>>taken. I admit to being obsessed with this challenge. I'm retired
>>from industrial electronics and now consider myself only a hobbyist so
>>the commercial equivalents of what I'm trying to do are just not
>>feasible.
>>
>>I still don't understand why the small pumps used in commercial
>>desoldering equipment far outperform the shop vac I had tried. The
>>shop vac experiment was only an overkill step in an attempt to begin
>>fine tuning the solder sucker idea.
>>
>
> High volume is not necessarily high vacuum. You will have to measure
> the vacuum. My little 170 cfm radon fan will suck two inches of water.
>
> greg
>

you can buy a venturi vacuum generator from Harbor Freight at very low
cost,they make one for evacuation auto air conditioning systems.
It needs a compressed air line. it will work continuously,off a small
compressor.

--
Jim Yanik
jyanik
at
localnet
dot com

==============================================================================
TOPIC: So, who's the king of finding data sheets ... ?
http://groups.google.com/group/sci.electronics.repair/t/4e444c319ac55fa0?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Jul 1 2010 5:34 pm
From: "Arfa Daily"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:i0hqtr$j8g$1@news-01.bur.connect.com.au...
>
> "Arfa Daily is off with the Goblins & Pixies"
>
>
>>> Do you still think that Marshall amps were designed by Jim Marshall ??
>>>
>>
>> What's that got to do with this thread ?
>
>
> ** Proves my point.
>
>
>
> ... Phil
>

Well actually, that rather proves mine. You're in the wrong thread
altogether for that one, but of course, stupid headed as you are, you hadn't
even noticed, had you ? What a plank ... :-)))

Arfa

== 2 of 2 ==
Date: Thurs, Jul 1 2010 5:39 pm
From: "Phil Allison"

"Arfa Daily is off with the Goblins & Pixies"
>
>>
>>>> Do you still think that Marshall amps were designed by Jim Marshall ??
>>>>
>>>
>>> What's that got to do with this thread ?
>>
>>
>> ** Proves my point.
>>
>
> Well actually, that rather proves mine.

** Have to be off with the pixies to think that.

> You're in the wrong thread

** You are in this thread and I am talking about you posting absolute crap.

Makes it 100% on topic.

.... Phil

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