sci.electronics.repair@googlegroups.com

Today's topics:

* flyback - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/273b5787d226bb6e?hl=en
* OT -- switching heating elements - 6 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/2359de19aee3537a?hl=en
* Guitar Pickups Coil Ringing Test Electric Testing PUP - 2 messages, 2
authors
http://groups.google.com/group/sci.electronics.repair/t/3f84b39bfef04db0?hl=en
* Blocking 425-336-8351 Robot Caller Parasite - 3 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/ed4180d1215897c7?hl=en

==============================================================================
TOPIC: flyback
http://groups.google.com/group/sci.electronics.repair/t/273b5787d226bb6e?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Jun 19 2011 4:16 pm
From: John-Del

On Jun 18, 4:36 pm, "Vince Schmitt" <vschmit...@gmail.com> wrote:
> Hi!
> I need to know the draw # for a flyback transformer  for an RCA Chassis
> CTC203AAA9.
>                                                           Thank yoy
>                                                              Vince

Database shows part number 244229 for your chassis version, but TCE
TVs have had issues with the numbers on the original fly needing to be
researched. Do you have the original and are the numbers legible?

John

== 2 of 2 ==
Date: Sun, Jun 19 2011 8:50 pm
From: Franc Zabkar

On Sun, 19 Jun 2011 16:16:37 -0700 (PDT), John-Del <ohger1s@aol.com>
put finger to keyboard and composed:

>On Jun 18, 4:36 pm, "Vince Schmitt" <vschmit...@gmail.com> wrote:
>> Hi!
>> I need to know the draw # for a flyback transformer  for an RCA Chassis
>> CTC203AAA9.
>
>Database shows part number 244229 for your chassis version ...

FYI, here is a HR Diemen substitute:
http://www.hrdiemen.es/products/index.php?command=search&by=brand&q=rca&offset=240

Unfortunately its information URL gives me an "internal server error":
http://www.hrdiemen.es/products/index.php?command=viewProduct&id=7313

It usually has a winding diagram with voltage information.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

==============================================================================
TOPIC: OT -- switching heating elements
http://groups.google.com/group/sci.electronics.repair/t/2359de19aee3537a?hl=en
==============================================================================

== 1 of 6 ==
Date: Sun, Jun 19 2011 5:06 pm
From: klem kedidelhopper

On Jun 19, 4:54 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:
> <PlainB...@yawhoo.com> wrote in message
>
> news:6tmsv6t6b0f46pn2ufmhj3mnokpskrb765@4ax.com...
>
>
>
> > On Sat, 18 Jun 2011 17:57:14 -0700, "William Sommerwerck"
> > <grizzledgee...@comcast.net> wrote:
> >> I just had to replace the bottom element in my GE oven, and discovered --
> to
> >> my great surprise -- that one side of the element is always "hot" -- that
> >> is, it has voltage on it. I will be calling Appliance Park next week and
> >> verbally tearing someone a new oven cavity.
> >> Is this normal? And if it is, is it for some reason other than saving
>
> money?
>
> > That is common. The resistance element is encapsulated in a
> > protective sheath. You cannot remove the heating element without
> > removing the back of the appliance. I would wager the appliance was
> > shipped with a warning label indicating it should be removed only by
> > qualified servicers.
>
> You don't have to take off the back of the oven. You can remove the element
> in situ. Just undo two 1/4" hex-head screws, pull out the base of the
> element a bit, and pull off the friction-fit connectors.

Well at least one side of the line is disconnected. Thank God for
small favors. So when you reach inside the oven and pull the hot
terminal off the element while you're leaning on the open door with
your chest, you only pass 120 through you heart....... Lenny

== 2 of 6 ==
Date: Sun, Jun 19 2011 5:14 pm
From: "William Sommerwerck"

"klem kedidelhopper" <captainvideo462009@gmail.com> wrote in message
news:c57a5c52-9fa3-44b0-9d97-2d4c08bf27f6@dq9g2000vbb.googlegroups.com...

>> You don't have to take off the back of the oven. You can remove the
>> element in situ. Just undo two 1/4" hex-head screws, pull out the base
>> of the element a bit, and pull off the friction-fit connectors.

> Well at least one side of the line is disconnected.

If both sides were connected, the element would be on! Wouldn't it?

> Thank God for small favors. So when you reach inside the oven
> and pull the hot terminal off the element while you're leaning on
> the open door with your chest, you only pass 120 through you heart.

Well, I was clothed. And the door was off.

== 3 of 6 ==
Date: Sun, Jun 19 2011 5:16 pm
From: "Ron D."

Triac controlled heaters would only switch one side. The disconnect
is responsible for switching both.

I've only seen one piece of industrial equipment that had a breaker
in the neutral. Basically 3 huge HIGH POWER like 15 kW*3 picture
tube like power supplies BUT VERY HIGH POWER. 15 kV at 3 amps.

The system required 70 Amp 3 phase 208 VAC to operate. Blink and your
dead. Keys are required to get passed the access doors on the
equipment.

== 4 of 6 ==
Date: Sun, Jun 19 2011 6:01 pm
From: "William Sommerwerck"

"Ron D." <ron.dozier@gmail.com> wrote in message
news:934e1a22-dd8b-414f-8208-86bdbd6f3b28@a10g2000vbz.googlegroups.com...

> Triac controlled heaters would only switch one side. The disconnect
> is responsible for switching both.

> I've only seen one piece of industrial equipment that had a breaker
> in the neutral. Basically 3 huge HIGH POWER like 15 kW*3 picture
> tube like power supplies BUT VERY HIGH POWER. 15 kV at 3 amps.

> The system required 70 Amp 3 phase 208 VAC to operate. Blink and
> you're dead. Keys are required to get passed the access doors on the
> equipment.

For those who enjoy calling me an idiot... I used to service klystrons with
20kV anode supplies. One was vehwy, vehwy kehful around these. You not only
made sure the power was off, but you used a conductive pole to short the
supply.

== 5 of 6 ==
Date: Sun, Jun 19 2011 7:32 pm
From: Sylvia Else

On 20/06/2011 12:52 AM, nesesu wrote:
> On Jun 18, 8:42 pm, Sylvia Else<syl...@not.here.invalid> wrote:
>> On 19/06/2011 1:20 PM, William Sommerwerck wrote:
>>
>>>>> I should have explained that I went to remove the element without
>>>>> opening the breaker -- on the assumption that no engineer in his
>>>>> right mind would leave one side of the heating element powered.
>>
>>>> Are you stupid? NOTHING gets worked on while connected to power.
>>
>>> "Foolish" might be more apt than "stupid". And people commonly work on
>>> powered TVs and other electronic equipment -- with proper precautions, of
>>> course.
>>
>>> We still need an answer to the original question... Why?
>>
>> I think it's perfectly normal for appliances to switch only one pole of
>> the power supply, that pole being the live one. Same with power points
>> and light switches. I don't think I've seen an appliance with a double
>> power power switch.
>>
>> What's not normal, and dangerous, is for the neutral wire to be the one
>> switched. Either the oven is miswired internally, is miswired to the
>> mains supply, or the mains supply is miswired. Whichever it is needs to
>> be fixed.
>>
>> Sylvia.
>
> We are talking at cross purposes here. In the UK and Australia, the
> 240V has one side neutral and the other 'hot' while in North America
> the 240V is both sides hot and centre neutral. In my stove the oven
> thermostat is the typical single pole switch in one side of the
> element circuit, but both sides pass through the 'oven function'
> selector switch that offers 'OFF', 'Bake', 'Broil' and 'Clean'. When
> that switch is OFF then the element is dsconnected from both hot
> feeds.
> In Canada, a heating thermostat for controlling 240V space heaters
> [permanently connected] may be a single pole type, but if it has an
> 'OFF' position marked, it MUST open both circuits.
>
> Neil S.

It's true that I had overlooked the strange :P approach to supplying
domestic power in North America.

One possibility that the OP needs to address is that the switch is
simply broken, or has one pole bridged by a wire.

But either way, I hold with the consensus here - you don't start taking
appliances apart while any part of them is powered, which includes their
switches. (But pleads guilty to removing and installing boards on PCs
while they're on standby!).

Sylvia.

== 6 of 6 ==
Date: Sun, Jun 19 2011 8:23 pm
From: spamtrap1888

On Jun 19, 5:14 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:
> "klem kedidelhopper" <captainvideo462...@gmail.com> wrote in message
>
> news:c57a5c52-9fa3-44b0-9d97-2d4c08bf27f6@dq9g2000vbb.googlegroups.com...
>
> >> You don't have to take off the back of the oven. You can remove the
> >> element in situ. Just undo two 1/4" hex-head screws, pull out the base
> >> of the element a bit, and pull off the friction-fit connectors.
> > Well at least one side of the line is disconnected.
>
> If both sides were connected, the element would be on! Wouldn't it?
>

But you wouldn't be replacing the element if it was on, right?

==============================================================================
TOPIC: Guitar Pickups Coil Ringing Test Electric Testing PUP
http://groups.google.com/group/sci.electronics.repair/t/3f84b39bfef04db0?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Jun 19 2011 7:15 pm
From: "Phil Allison"

"Wild_Bill"
>
> I remembered that the Z-Meter manuals specifically state that these
> testers work with inductors with powdered iron/ferrite-type cores (not
> steel such as power transformers), so I removed the steel screws, but the
> coils still only have 4 rings.

** The pickup has a steel ( possibly Alnico ) magnet and soft iron pole
pieces, this makes for a lossy inductor - bit like a normal loudspeaker
voice coil is.

If you remove all of that, the inductance goes down and you have a low Q
inductor because of the high resistance.

... Phil

== 2 of 2 ==
Date: Mon, Jun 20 2011 12:08 am
From: "Wild_Bill"

I attempted to explain that I've disassembled the humbucker pickup,
separated the 2 coils, and have removed all the metal influences from the
coils.
The magnet, pole pieces, screws, frame plate and cover have been removed and
set aside.

Just a plastic bobbin and hundreds of turns of wire.. there is no metal,
other than the coil of wire.
The desk where I'm checking the coils is wood.

At that point, there weren't even any long signal leads attached to the
coil.

So I've reassembled the pickup as originally wired, with a short pigtail of
shielded pickup coil cable.

I added an inline 1/4" jack to the pigtail, and plugged my VOX AM30 Amplug
headphone amplifier into the pigtail, and held the pickup near the guitar
strings (in the open space between the guitar's neck and bridge pickups..

and Buhh-Zinga! plenty of output from this Epiphone humbucker pickup.

This isn't a definitive performance test, but the notes sound very clear and
strong for all the strings.
I immediately plugged the H-P amp into the guitar, and the Epiphone pickup
sounded essentially the same as the guitar's DiMarzio DP155 bridge pickup.

I hadn't suspected that the Epiphone pickup was bad, but I wasn't sure since
it hadn't been installed in a guitar since I've had it.

BTW, I didn't place the metal cover back on the pickup, and I'm aware that a
metal cover will create a fairly large area for eddy current to pass, and
slightly affect the peak frequency.

I think I'll make a little gantry for suspending test pickups over the
guitar strings, for a quick bench check.

But I still don't know why the Bare coils didn't ring higher than 4 rings.
It's possible that shorted turns could exist even though the output seems to
be OK.

Oh, and forgot to mench.. the inductance measurement for the combined coils
in this pickup (when it's fully assembled) reads about 5.5 H.

--
Cheers,
WB
.............

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:967oqaFks6U1@mid.individual.net...
>
> "Wild_Bill"
>>
>> I remembered that the Z-Meter manuals specifically state that these
>> testers work with inductors with powdered iron/ferrite-type cores (not
>> steel such as power transformers), so I removed the steel screws, but the
>> coils still only have 4 rings.
>
>
> ** The pickup has a steel ( possibly Alnico ) magnet and soft iron pole
> pieces, this makes for a lossy inductor - bit like a normal loudspeaker
> voice coil is.
>
> If you remove all of that, the inductance goes down and you have a low Q
> inductor because of the high resistance.
>
>
> ... Phil
>
>
>
>
>

==============================================================================
TOPIC: Blocking 425-336-8351 Robot Caller Parasite
http://groups.google.com/group/sci.electronics.repair/t/ed4180d1215897c7?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Jun 19 2011 7:25 pm
From: Jeff Liebermann

On Sat, 18 Jun 2011 22:54:04 +0000 (UTC), "Geoffrey S. Mendelson"
<gsm@mendelson.com> wrote:

>Cell phones cost a lot to call, landlines less and the secondary provider
>landlines are very cheap.

We have number portability in the US, which means the prefix can no
longer be used to determine the type of phone or the general location.

For cell phones, while the rest of the planet the caller pays, in the
US, the call recipient pays, making cell phone spam profitable.

The Federal Trade Commission do not call list is widely ignored by
international telemarketers.
<http://www.donotcall.gov>
<http://transition.fcc.gov/cgb/donotcall/>
The do not call list does not cover calls within a State. However
most states simply pass the problem to the federal system. For
example, California:
<http://oag.ca.gov/donotcall>
Calls are still permitted from:
(1) collection agencies and creditors,
(2) political organizations,
(3) charities,
(4) pollsters and individuals doing surveys and
(5) companies with whom you have an existing business relationship.
A company may call you for 18 months after you make a purchase
or three months after you submit an inquiry or application.

All of the phone solicitations I receive fall into these exceptions.

--
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

== 2 of 3 ==
Date: Sun, Jun 19 2011 7:41 pm
From: dplatt@radagast.org (Dave Platt)

In article <h40qv61un9p4749uso1q3rn89du4o3gil6@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

>About 10 years ago, I threw together a home IVR system that almost
>worked. It would grab and store the caller ID, but not ring the phone
>no matter how many times the caller would ring. However, if the same
>caller ID called back within about 3 minutes, the phone would ring
>normally. I would tell my friends and accomplises to call twice. The
>problem was that many callers didn't have caller ID active. I also
>missed some important calls.

I ended up doing something vaguely similar, recently, when we switched
my wife's business line from a dedicated AT&T landline to a VoIP
connection. We terminate the incoming VoIP call at a small home
server running Asterisk, which has some blacklisting capabilities
built in, and the potential for more via dialplan scripting.

My current recipe:

(1) Any blacklisted number (the prolific "ADA" phonespammer being the
lead among them) - the call is rejected with a "congestion"
response. Phone never rings - from the telco's point of view the
call is never answered, and the caller hears a fast-busy.

[2] Calls which provide caller-ID, from any of the area codes near
ours (most of my wife's clients) or a couple of distant cities...
rings the business phone / answering machine immediately.

[3] All others - answer, robo-voice "Please wait to be connected",
wait 10 seconds, ring the business phone if the call is still alive.

Rule (3) seems to deter most sales-slime... they hang up rather than
wait.

I've also got a couple of three-digit codes programmed in, to add the
most recent caller to the blacklist, or remove if in error.

The total number of nuisance calls she has to deal with is down by
around 90% since the old land-line days.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

== 3 of 3 ==
Date: Sun, Jun 19 2011 8:30 pm
From: Jeff Liebermann

On Sun, 19 Jun 2011 19:41:30 -0700, dplatt@radagast.org (Dave Platt)
wrote:

>I ended up doing something vaguely similar, recently, when we switched
>my wife's business line from a dedicated AT&T landline to a VoIP
>connection.

Note that business to business telemarketing calls are exempt from the
do not call rules:
<http://business.ftc.gov/documents/alt129-qa-telemarketers-sellers-about-dnc-provisions-tsr#exempt>

>We terminate the incoming VoIP call at a small home
>server running Asterisk, which has some blacklisting capabilities
>built in, and the potential for more via dialplan scripting.

Android cell phone blacklist software (with huge blacklist of numbers
included).
<http://www.everycall.us/product/call-control-android/>
Same with OOma VoIP:
<http://ooma.custhelp.com/app/answers/detail/a_id/194/~/personal-and-community-blacklists>

>My current recipe:
>
>(1) Any blacklisted number (the prolific "ADA" phonespammer being the
> lead among them) - the call is rejected with a "congestion"
> response. Phone never rings - from the telco's point of view the
> call is never answered, and the caller hears a fast-busy.
>
>[2] Calls which provide caller-ID, from any of the area codes near
> ours (most of my wife's clients) or a couple of distant cities...
> rings the business phone / answering machine immediately.
>
>[3] All others - answer, robo-voice "Please wait to be connected",
> wait 10 seconds, ring the business phone if the call is still alive.
>
>Rule (3) seems to deter most sales-slime... they hang up rather than
>wait.

Nice. That should work. The basic idea is if unidentified, to waste
their time. Since telemarketers don't like to sit on hold, they just
leave. However, they often come back. I was just hanging up on one
idiot caller, who would just wait about 30 minutes, and call again. He
eventually went away when I asked for the name of his telemarketing
organization.

On a customers system, I plagiarized a script I found on the net, that
was designed to irritate telemarketers.
<http://www.voip-info.org/wiki/view/Asterisk+AEL+Telemarketer+Torture>
It was fun for a while, until a very important caller got stuck with
it.

I later had it making Strowger switch sounds before ringing.
<http://www.seg.co.uk/telecomm/step1.wav>
Those with a clue thought it was cute. Those too young to remember a
step CO, were confused.

>I've also got a couple of three-digit codes programmed in, to add the
>most recent caller to the blacklist, or remove if in error.

Also nice. List management is not fun.

>The total number of nuisance calls she has to deal with is down by
>around 90% since the old land-line days.

I must be leading a charmed life. I get very few unsolicited calls on
any of my 4 assorted numbers. The few that I get are from exempt
organizations, my long lost college, a few clueless head hunters, and
desperate usenet readers needing help with their wireless. I guess
being mean and nasty pays.

--
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

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