sci.electronics.repair@googlegroups.com

Today's topics:

* general question: mainboard caps - 5 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/1bf5ee3341246b6a?hl=en
* TV turns off plugged into surge protector - 4 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/755764111f5ddb2a?hl=en
* Help identifying components - 10 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/0a66446e99cc4d03?hl=en
* Pinch Rollers Hi8 Video Heads Select By Size not Model Teac Military VCR V-
80AB V-800AB - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/5e0cad3ae4a667f3?hl=en
* Cheap Coach Handbags Chanel Handbags DG Handbags GUCCI Handbags Wholesale(
http://www.24hoursneakers.com/) (PayPal Payment) - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/fde4b1f7a95d5145?hl=en

==============================================================================
TOPIC: general question: mainboard caps
http://groups.google.com/group/sci.electronics.repair/t/1bf5ee3341246b6a?hl=en
==============================================================================

== 1 of 5 ==
Date: Fri, Sep 24 2010 3:58 pm
From: Bob Villa

On Sep 24, 2:45 pm, Bob Villa <pheeh.z...@gmail.com> wrote:
> On Sep 24, 6:00 am, Jeff Liebermann <je...@cruzio.com> wrote:
>
>
>
> > On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa
>
> > <pheeh.z...@gmail.com> wrote:
> > >Thanks to all for your expertise in de-soldering...there is a world of
> > >experience here, and worth much.
> > >I have never had luck with braided wire...but evidently is works for
> > >some. (I never have any luck with super-glue either!)
>
> > Super-glue doesn't do very well for desoldering (or soldering) a
> > printed circuit boards.  
>
> > --
> > Jeff Liebermann     je...@cruzio.com
> > 150 Felker St #D    http://www.LearnByDestroying.com
> > Santa Cruz CA 95060http://802.11junk.com
> > Skype: JeffLiebermann     AE6KS    831-336-2558
>
> This was unrelated and anecdotal. But, thanks again.

Well, actually, it is related...many ppl seem to be able to get
satisfactory results using braid to de-solder and getting super glue
to stick to the proper thing. (note: not necessarily the same ppl or
at the same time) I do not.
HTMS

== 2 of 5 ==
Date: Fri, Sep 24 2010 3:15 pm
From: mjb@signal11.invalid (Mike)

In article <l1oi96d6hks2s9p99efb7806j9avu1h2o3@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:
>While a proper vacuum desoldering station is nice, you can get away
>with using a solder sucker.

Also consider using a small length of *non-melting* (e.g. butyl rubber)
sleeve that will push fit over the business end of the sucker, set to
be about 8mm past the end.

Most of the cheap ones have a nylon-ish end that gets melted very easily
and won't make a good vacuum seal against the board.

With a rubbery end, you get a better seal and consequently better
clearance THROUGH the hole, even if you are at a slight angle to
the board. No good having a vacuum that escapes along the face of the
board.

It also saves the plastic nozzle getting sozzled!

--
--------------------------------------+------------------------------------
Mike Brown: mjb[-at-]signal11.org.uk | http://www.signal11.org.uk

== 3 of 5 ==
Date: Fri, Sep 24 2010 6:27 pm
From: Jeff Liebermann

On Fri, 24 Sep 2010 15:58:11 -0700 (PDT), Bob Villa
<pheeh.zero@gmail.com> wrote:

>Well, actually, it is related...many ppl seem to be able to get
>satisfactory results using braid to de-solder and getting super glue
>to stick to the proper thing. (note: not necessarily the same ppl or
>at the same time) I do not.

The trick is to use the braid for desoldering and the super glue for
adhesive purposes, and not get them mixed.

Try some epoxy made for plastics:
<http://www.loctiteproducts.com/p/13/7/epxy_plstc_s/overview/Loctite-Epoxy-Plastic-Bonder.htm>

As with all adhesives, the tricks are:
1. Make sure the adhesive is compatible. If the part flexes, you
don't want a really brittle adhesive. If it's porous, you want
something that has plenty of filler.
2. Clean the parts with whatever solvent you find useful. Make sure
it evaporates completely and there's no water residue (such as what
you'll get with alcohol) on the parts.
3. Use as thin a layer of glue as possible.
4. Use clamping pressure and let everything harden per instructions.

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

== 4 of 5 ==
Date: Fri, Sep 24 2010 6:35 pm
From: Jeff Liebermann

On Fri, 24 Sep 2010 12:44:12 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

>Went shopping... got a plunger for $11 at Fry's. Harbor Freight has a
>180W solder gun for $10... remembered pointers here on high power for
>Pb-free solder... is the gun a good idea, or too hot?

This one? 1135F is far too hot:
<http://www.harborfreight.com/welding/soldering/180-watt-industrial-soldering-gun-4328.html>
Take it back or give it to your worst enemy. It's totally unsuitable
for soldering printed circuit boards. You need a temperature
controlled iron, with replaceable tips (for different types of work).
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

== 5 of 5 ==
Date: Fri, Sep 24 2010 11:31 pm
From: Michael

On Sep 24, 6:35 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Fri, 24 Sep 2010 12:44:12 -0700 (PDT), Michael
>
> <mrdarr...@gmail.com> wrote:
> >Went shopping... got a plunger for $11 at Fry's.  Harbor Freight has a
> >180W solder gun for $10... remembered pointers here on high power for
> >Pb-free solder... is the gun a good idea, or too hot?
>
> This one?  1135F is far too hot:
> <http://www.harborfreight.com/welding/soldering/180-watt-industrial-so...>
> Take it back or give it to your worst enemy.  It's totally unsuitable
> for soldering printed circuit boards.  You need a temperature
> controlled iron, with replaceable tips (for different types of work).
> --
> # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
> # 831-336-2558
> #http://802.11junk.com              je...@cruzio.com
> #http://www.LearnByDestroying.com              AE6KS

Ok thanks. Didn't buy it... decided to shop around a bit first.
Thought if it is too high a power, just shut of power immediately once
the solder melts... but ok, good idea, I'll pass on this.

==============================================================================
TOPIC: TV turns off plugged into surge protector
http://groups.google.com/group/sci.electronics.repair/t/755764111f5ddb2a?hl=en
==============================================================================

== 1 of 4 ==
Date: Fri, Sep 24 2010 4:54 pm
From: westom

On Sep 24, 4:57 pm, Archon <Chipbee40_Spa...@yahoo.com> wrote:
> Its a while back now but I think it had a MOV inside and some crappy
> little circuit board. I didn't spend much time looking at it, it annoyed
> me as I needed to use the equipment connected to it and didn't have a
> spare strip available. So very hasty hatchet job.

Any protector damaged by a surge was never doing any protection. In
any facility that can never have damage, the protector is always
located at the service entrance (ie breaker box) with the always
required shot connection to earth.

TV connects directly to AC mains if plugged into that cheap
protector. Only thing between the TV and AC mains a 15 amp circuit
breaker. CB exists on every power strip - with or without protector
circuits. Nothing inside a power strip protector changes electricity.

If the wall receptacle is worn (must be replaced), then a two prong
TV plug can be intermittent. A three prong power strip plug would be
held firmly. TVs also have internal protector circuits. That
safety lockout is reset only by unplugging the TV. Two possible
reasons for TV failure.

== 2 of 4 ==
Date: Fri, Sep 24 2010 5:02 pm
From: "William Sommerwerck"

> Any protector damaged by a surge was never doing
> any protection.

Not according to APC, et al. Most equipment-replacement warrantees require
that the surge protector be damaged. By the manufacturer's reasoning, if the
protector wasn't damaged, then it must have absorbed the surge -- and
therefore the equipment could not have been damaged.

== 3 of 4 ==
Date: Fri, Sep 24 2010 5:20 pm
From: Archon

On 9/24/2010 7:54 PM, westom wrote:
> On Sep 24, 4:57 pm, Archon<Chipbee40_Spa...@yahoo.com> wrote:
>> Its a while back now but I think it had a MOV inside and some crappy
>> little circuit board. I didn't spend much time looking at it, it annoyed
>> me as I needed to use the equipment connected to it and didn't have a
>> spare strip available. So very hasty hatchet job.
>
> Any protector damaged by a surge was never doing any protection. In
> any facility that can never have damage, the protector is always
> located at the service entrance (ie breaker box) with the always
> required shot connection to earth.
>
> TV connects directly to AC mains if plugged into that cheap
> protector. Only thing between the TV and AC mains a 15 amp circuit
> breaker. CB exists on every power strip - with or without protector
> circuits. Nothing inside a power strip protector changes electricity.
>
> If the wall receptacle is worn (must be replaced), then a two prong
> TV plug can be intermittent. A three prong power strip plug would be
> held firmly. TVs also have internal protector circuits. That
> safety lockout is reset only by unplugging the TV. Two possible
> reasons for TV failure.

Read up on MOV's

From Belkin :

So what does this mean with regard to surge protection? Well, a typical
surge protector (PowerSquid included) utilizes Metal Oxide Varistors
(MOVs) to redirect electric currents above a specified voltage (clamping
voltage) instead of allowing the surge to enter the connected equipment.
The MOV absorbs the excess electrical energy - here is where the joule
comes in - and dissipates it as heat energy. MOVs are rated by the
number of joules that they can absorb, which is a finite number.
Ultimately, after the MOVs absorb all of the joules that they can, the
surge protector will activate its Tripwire Circuit and sacrifice itself
for the betterment of the connected equipment. In other words: you will
have to replace your surge protector,

JC

== 4 of 4 ==
Date: Fri, Sep 24 2010 5:54 pm
From: "Michael A. Terrell"

William Sommerwerck wrote:
>
> > Any protector damaged by a surge was never doing
> > any protection.
>
> Not according to APC, et al. Most equipment-replacement warrantees require
> that the surge protector be damaged. By the manufacturer's reasoning, if the
> protector wasn't damaged, then it must have absorbed the surge -- and
> therefore the equipment could not have been damaged.

William, 'westom' AKA 'W_Tom' is a well known troll with a hard-on
for people who use surge protectors. No matter what evidence you
provide, he will deny it and call you an idiot.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

==============================================================================
TOPIC: Help identifying components
http://groups.google.com/group/sci.electronics.repair/t/0a66446e99cc4d03?hl=en
==============================================================================

== 1 of 10 ==
Date: Fri, Sep 24 2010 9:28 pm
From: DaveC

Black diode, smaller than 1Nxxx, green band and green test: "R47".

Glass diode with yellow band. No other markings.

Thanks.

== 2 of 10 ==
Date: Fri, Sep 24 2010 9:39 pm
From: "tm"

"DaveC" <invalid@invalid.net> wrote in message
news:0001HW.C8C2C86803107F42B01AD9AF@news.eternal-september.org...
> Black diode, smaller than 1Nxxx, green band and green test: "R47".
>
> Glass diode with yellow band. No other markings.
>
> Thanks.
>
What are they in? A little context would help.

== 3 of 10 ==
Date: Fri, Sep 24 2010 9:48 pm
From: DaveC

> Black diode, smaller than 1Nxxx, green band and green test: "R47".

should say 'green text: "R47" '.

Thanks.

== 4 of 10 ==
Date: Fri, Sep 24 2010 9:59 pm
From: DaveC

> What are they in? A little context would help.

The circuit is in a Hakko 472 desolder station. It controls the switching on
and off of the vacuum pump motor and vacuum solenoid valve.

Thanks.

== 5 of 10 ==
Date: Fri, Sep 24 2010 10:01 pm
From: "Tim Williams"

DIAC?

I have some diodes of similar appearance on RF equipment. I'm guessing
they are either schottky or varactor. YMMV, could be a manufacturer
thing.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"DaveC" <invalid@invalid.net> wrote in message
news:0001HW.C8C2CFB2031234C6B01AD9AF@news.eternal-september.org...
>> What are they in? A little context would help.
>
> The circuit is in a Hakko 472 desolder station. It controls the
> switching on
> and off of the vacuum pump motor and vacuum solenoid valve.
>
> Thanks.
>

== 6 of 10 ==
Date: Fri, Sep 24 2010 10:04 pm
From: DaveC

> Second unit is probably a Ge diode like 1N34A

Measures 0.59v drop. So: silicon.

== 7 of 10 ==
Date: Fri, Sep 24 2010 10:16 pm
From: DaveC

Does the fact that both show ~ 0.6 v-drop rule out zeners?

Thanks.

== 8 of 10 ==
Date: Fri, Sep 24 2010 10:48 pm
From: "tm"

"DaveC" <invalid@invalid.net> wrote in message
news:0001HW.C8C2D3CC03132ACCB01AD9AF@news.eternal-september.org...
> Does the fact that both show ~ 0.6 v-drop rule out zeners?
>
> Thanks.
>

No, only that they are most likely silicon. The zener effect is the reverse
breakdown
voltage. You need to dope out the circuit more to see if it could be a
zener.

== 9 of 10 ==
Date: Fri, Sep 24 2010 10:59 pm
From: "tm"

"DaveC" <invalid@invalid.net> wrote in message
news:0001HW.C8C2CFB2031234C6B01AD9AF@news.eternal-september.org...
>> What are they in? A little context would help.
>
> The circuit is in a Hakko 472 desolder station. It controls the switching
> on
> and off of the vacuum pump motor and vacuum solenoid valve.
>
> Thanks.
>

Are the vacuum pump and solenoid AC or DC devices?

Is there a SCR in there?

See if this schematic has any think close to what you have:

http://www.eserviceinfo.com/downloadsm/37779/Hakko_850B.html

tm

== 10 of 10 ==
Date: Sat, Sep 25 2010 1:11 am
From: Lostgallifreyan

DaveC <invalid@invalid.net> wrote in
news:0001HW.C8C2D3CC03132ACCB01AD9AF@news.eternal-september.org:

> Does the fact that both show ~ 0.6 v-drop rule out zeners?
>
> Thanks.
>
>

You sound like a man who imagines that by scrunchign his shoulders, no-one
will mind when he passes annopyingly several times through the same doorway.
>:)

And no. To test a zener you need to try a reverse voltage. Try a variable
voltage through a 10K resistor. A sine wave off a 30V transformer will do,
just look for the clipping voltages on a scope (or DC voltmeter if you add a
capacitor in parallel with the diode). Vz equals peak-peak voltage minus
about 0.58V. You may also have to remove one end of it from the circuit to be
certain.

==============================================================================
TOPIC: Pinch Rollers Hi8 Video Heads Select By Size not Model Teac Military
VCR V-80AB V-800AB
http://groups.google.com/group/sci.electronics.repair/t/5e0cad3ae4a667f3?hl=en
==============================================================================

== 1 of 1 ==
Date: Fri, Sep 24 2010 11:27 pm
From: Cydrome Leader

Wild_Bill <wb_wildbill@xspamyahoo.com> wrote:
> Any help in obtaining parts would be gratefully appreciated.
> I'd like to find a US supplier of Hi8/Video8 pinch rollers where I can
> select the rollers by the actual part dimensions instead of Brand-Model.
>
> I'd also like to find a supplier with the same selection for upper
> drum/video heads for Hi8 tape mechanisms.
>
> I haven't contacted ASTI, but they might be able to help with the head
> assemblies.
>
> The Hi8 video machines that I'd like to find parts for are Teac military
> AVTR airborne video tape recorder units. Some of the Teac Hi8 equipment has
> also been in use in airline aircraft as IFE in flight entertainment
> equipment.
> That particular division (aerospace products) of Teac was bought by a large
> military equipment supplier, Goodrich.
>
> Teac wasn't/isn't a VCR/camcorder manufacturer, and the tape transport
> mechanisms may be made by another major manufacturer, although the circuit
> board of the video heads is labeled Teac (but no part number).
> The hub of the head assembly is dated (yy. mm. dd), and I've seen other
> brands of heads that were dated the same way, but can't remember which
> brands.
>
> The head assemblies don't appear to have any special characteristics, just 2
> record/play heads and a FE flying erase head.
>
> --
> Cheers,
> WB
> .............

I'm going to ask who really made those transports- I know somebody that
used to service those things.

==============================================================================
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http://groups.google.com/group/sci.electronics.repair/t/fde4b1f7a95d5145?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Sep 25 2010 12:07 am
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