sci.electronics.repair@googlegroups.com

Today's topics:

* Two phases or not? - 4 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
* TEAC 1/2" Open-Reel Schematic Needed - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/576b66e4a8299d50?hl=en
* Our Heavenly Mother 5-3-01 - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/115f5947374d6dd2?hl=en
* Pet hates ? - 10 messages, 6 authors
http://groups.google.com/group/sci.electronics.repair/t/e7925b5c2233e9ec?hl=en
* Nickel plated polyimide--where to get? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/8bee83d05dbdcb50?hl=en

==============================================================================
TOPIC: Two phases or not?
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
==============================================================================

== 1 of 4 ==
Date: Sun, Jan 23 2011 4:47 pm
From: "Phil Allison"

"Wild_Bill"

>
> These comments are logical and correct representations of the power system
> that most of us use. For single phase motors, a 120VAC motor is a
> single-phase motor, just as a 240VAC motor is referred to as a
> single-phase motor, not a 2-phase motor because it's using 2 hot lines.

** Massive straw man fallacy.

Why am I not surprised it comes from a fucking TOP POSTER !!

.... Phil

== 2 of 4 ==
Date: Sun, Jan 23 2011 5:50 pm
From: David Nebenzahl

On 1/23/2011 4:44 PM Wild_Bill spake thus:

> These comments are logical and correct representations of the power system
> that most of us use. For single phase motors, a 120VAC motor is a
> single-phase motor, just as a 240VAC motor is referred to as a single-phase
> motor, not a 2-phase motor because it's using 2 hot lines.
>
> This issue is one that just gets argued endlessly by amateurs and intellects
> to no end.. essentially a waste of useful time on an issue that's widely
> misunderstood for all the wrong reasons.

I disagree entirely. Yes, in this case it's a semantic debate--what I
contend is actually 2-phase power (120-0-120 derived from a
center-tapped transformer) is not *called* that by the electric power
industry. It is, nonetheless, truly two phase power.

I think it's important because the idea of phases in electrical power is
an important one, even to a simpleton like the average electrician,
never mind the EE.

Example: if you're going to wire an Edison circuit (where two hots from
different phases, meaning different sides of the distribution panel, are
wired with a common neutral), you ought to understand electrical phases,
especially the consequences of two phases 180° apart. After all, that's
how the currents from the two sides cancel each other. Failure to grasp
such principles can, and do, lead to real-world consequences like
building fires.

> Pick the issue apart just for sport, if you like, but the majority of
> domestic power supplies are single-phase.. period.

> Look anywhere you can for a New 2-phase motor.

Who said anything about a 2-phase motor? Nobody, so far as I can tell.

I'm saying that the ENTIRE DOMESTIC POWER SUPPLY FROM THE SECONDARY OF
THE POWER COMPANY'S TRANFORMER is 2-phase. Once you plug in a 120 volt
anything, or even many 240 volt anythings, you're only using one phase.
Sheesh.

> The only individuals that would be describing a new motor as a 2-phase motor
> will be some misguided trainee or someone taking advantage of your stupidity
> of asking for one.

Again, where did this straw man come from?

Please notice that because of your non-standard top posting, any
previous replies have been cut off. Please do what 99% of others do here
and bottom post.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 3 of 4 ==
Date: Sun, Jan 23 2011 6:27 pm
From: Jamie

David Nebenzahl wrote:

> On 1/23/2011 4:44 PM Wild_Bill spake thus:
>
>> These comments are logical and correct representations of the power
>> system that most of us use. For single phase motors, a 120VAC motor is
>> a single-phase motor, just as a 240VAC motor is referred to as a
>> single-phase motor, not a 2-phase motor because it's using 2 hot lines.
>>
>> This issue is one that just gets argued endlessly by amateurs and
>> intellects to no end.. essentially a waste of useful time on an issue
>> that's widely misunderstood for all the wrong reasons.
>
>
> I disagree entirely. Yes, in this case it's a semantic debate--what I
> contend is actually 2-phase power (120-0-120 derived from a
> center-tapped transformer) is not *called* that by the electric power
> industry. It is, nonetheless, truly two phase power.
>
> I think it's important because the idea of phases in electrical power is
> an important one, even to a simpleton like the average electrician,
> never mind the EE.
>
> Example: if you're going to wire an Edison circuit (where two hots from
> different phases, meaning different sides of the distribution panel, are
> wired with a common neutral), you ought to understand electrical phases,
> especially the consequences of two phases 180° apart. After all, that's
> how the currents from the two sides cancel each other. Failure to grasp
> such principles can, and do, lead to real-world consequences like
> building fires.
>
>> Pick the issue apart just for sport, if you like, but the majority of
>> domestic power supplies are single-phase.. period.
>
>
>> Look anywhere you can for a New 2-phase motor.
>
>
> Who said anything about a 2-phase motor? Nobody, so far as I can tell.
>
> I'm saying that the ENTIRE DOMESTIC POWER SUPPLY FROM THE SECONDARY OF
> THE POWER COMPANY'S TRANFORMER is 2-phase. Once you plug in a 120 volt
> anything, or even many 240 volt anythings, you're only using one phase.
> Sheesh.
>
>> The only individuals that would be describing a new motor as a 2-phase
>> motor will be some misguided trainee or someone taking advantage of
>> your stupidity of asking for one.
>
>
> Again, where did this straw man come from?
>
> Please notice that because of your non-standard top posting, any
> previous replies have been cut off. Please do what 99% of others do here
> and bottom post.
>
>

Don't waste your breath. it's not worth the effort.

Knowing that you understand it should be enough..

And by the way, I was looking at a 3 wire motor today, 2 phases of 180
apart with CT to operate it (3 wire motor). It was attached to a gear
box and only ran one direction, but you could use it as a stepper
(servo) or full out run. Most likely some custom motor for an application.

Jamie

== 4 of 4 ==
Date: Sun, Jan 23 2011 10:35 pm
From: "Wild_Bill"

Jamie, what info is included on the motor's data plate/label? Is there a
capacitance included, with a low value of 25uF or less?

I think you may have been looking at a PSC permanent split capacitor motor..
although I haven't seen any rated at 180V. Most 3-wire motors are PSC types.

BTW, PSC motors aren't defined or referred to as 2-phase motors.
They may be specified for some particular rating as single-direction motors,
but they are reversible, in fact, fast stopping/reversing is one of the
features of PSC motors.
The gearheads, and especially the right-angle gearheads with encoders
attached are very versatile.

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

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:de5%o.16039$TZ4.6414@newsfe20.iad...
>
> Don't waste your breath. it's not worth the effort.
>
> Knowing that you understand it should be enough..
>
> And by the way, I was looking at a 3 wire motor today, 2 phases of 180
> apart with CT to operate it (3 wire motor). It was attached to a gear box
> and only ran one direction, but you could use it as a stepper (servo) or
> full out run. Most likely some custom motor for an application.
>
> Jamie
>
>

==============================================================================
TOPIC: TEAC 1/2" Open-Reel Schematic Needed
http://groups.google.com/group/sci.electronics.repair/t/576b66e4a8299d50?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jan 23 2011 6:40 pm
From: "Dave M"

Pimpom wrote:
> Phil Allison wrote:
>> "Chris F."
>>>
>>> I have a Teac Model 80-8 1/2" open reel machine I have to
>>> repair
>>> for a customer. This is the first 1/2", 8-track machine I've
>>> worked
>>> on and it's clear I'm going to need a schematic. The main
>>> problem is
>>> that some channels are sounding through to others; for
>>> example, with
>>> a signal connected to channel 1 only, it sounds over to
>>> channel 2
>>> and faintly to channel 3. This happens even when monitoring
>>> the
>>> input without a tape loaded, ruling out a head alignment
>>> issue.
>>> Any advice, or especially a schematic, would be appreciated.
>>
>>
>> ** Have you tried shorting the unused inputs while testing ??
>>
>> This is how the recorder would be used in practice.
>>
> If that doesn't eliminate the crosstalk, I'd suspect a common
> power supply filter in the low-level stages. Perhaps a dried-up
> cap.

There's a Teac-specific web site at https://www.daeinconline.com/index.html.
Send them an email and see if they can help with your problem. They might
even have a manual on the bottom shelf..
--
David
dgminala at mediacombb dot net

==============================================================================
TOPIC: Our Heavenly Mother 5-3-01
http://groups.google.com/group/sci.electronics.repair/t/115f5947374d6dd2?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Jan 23 2011 7:28 pm
From: John Robertson

mier wrote:
> Our Heavenly Mother says,
....
> All Revelations are delivered spontaneously
> and continuously as witnessed by all those present at the time.
> Copyright 1996 FMK
> This is used with the permission of the copyright holder.
>
>

What exactly is your problem? You posted in a tech service forum.

Are you unable to contact your Heavenly Mother? Perhaps her number is
unlisted or there is no dial tone? It is hard to deal with signal
rejection, most people would call for tech support as you have, but I'm
not sure that we can help you as you didn't exactly specify what the
problem was and when it started (perhaps in 1996?).

We need more information!

John :-#)#

== 2 of 3 ==
Date: Sun, Jan 23 2011 8:09 pm
From: Jeffrey Angus

On 1/23/2011 4:30 PM, mier wrote:
> As I close My Words, I beseech you to always remember you are
> never alone, because within you, you have a Portion of The Creator
> given at the moment of conception, and will remain until The Father
> causes It in some way to return to Him.
>

The best part of you ran down your father's leg.

Jeff

== 3 of 3 ==
Date: Sun, Jan 23 2011 8:21 pm
From: Allodoxaphobia

On Sun, 23 Jan 2011 19:28:34 -0800, John Robertson wrote:
> mier wrote:
>> Our Heavenly Mother says,
> ....
>> All Revelations are delivered spontaneously
>> and continuously as witnessed by all those present at the time.
>> Copyright 1996 FMK
>> This is used with the permission of the copyright holder.
>
> What exactly is your problem? You posted in a tech service forum.
>
> Are you unable to contact your Heavenly Mother? Perhaps her number is
> unlisted or there is no dial tone? It is hard to deal with signal
> rejection, most people would call for tech support as you have, but I'm
> not sure that we can help you as you didn't exactly specify what the
> problem was and when it started (perhaps in 1996?).
>
> We need more information!

She probably has Caller ID and blocks his number.

==============================================================================
TOPIC: Pet hates ?
http://groups.google.com/group/sci.electronics.repair/t/e7925b5c2233e9ec?hl=en
==============================================================================

== 1 of 10 ==
Date: Sun, Jan 23 2011 8:14 pm
From: "Michael Kennedy"

"Allodoxaphobia" <knock_yourself_out@example.net> wrote in message
news:slrnijonj3.2as3.knock_yourself_out@shell.config.com...
> On Sun, 23 Jan 2011 23:02:48 +0900, Michael Kennedy wrote:
>>
>> California is strange..
>
> It's only January and we have
> the winner for The Understatement Of 2011.

I was trying to have some restraint and hold back.

== 2 of 10 ==
Date: Sun, Jan 23 2011 8:26 pm
From: "Michael Kennedy"

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:e4OdnaoKnYYAs6XQnZ2dnUVZ_sOdnZ2d@earthlink.com...
>
> JW wrote:
>>
>> On Thu, 20 Jan 2011 05:29:16 -0600 "Mark Zacharias"
>> <mark_zacharias@sbcglobal.net> wrote in Message id:
>> <4d381c8b$0$19215$c3e8da3$aae71a0a@news.astraweb.com>:
>>
>> >Packing peanuts.
>>
>> There's a good one. Especially when the humidity is very low, and the
>> peanuts are all broken up in pieces!
>
>
> Low humidity is rarely a problem in Florida. :(
>
>
> --
> You can't fix stupid. You can't even put a band-aid on it, because it's
> Teflon coated.

Yeah.. One time I was going to paint something. The can of spray paint said
to only use it in 50% or less humidity. I laughed when I read that and
thought there must be less than 20 days a year that would have low enough
humidity to paint this thing..

== 3 of 10 ==
Date: Sun, Jan 23 2011 8:37 pm
From: "Michael A. Terrell"

Michael Kennedy wrote:
>
> "Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
> news:e4OdnaoKnYYAs6XQnZ2dnUVZ_sOdnZ2d@earthlink.com...
> >
> > JW wrote:
> >>
> >> On Thu, 20 Jan 2011 05:29:16 -0600 "Mark Zacharias"
> >> <mark_zacharias@sbcglobal.net> wrote in Message id:
> >> <4d381c8b$0$19215$c3e8da3$aae71a0a@news.astraweb.com>:
> >>
> >> >Packing peanuts.
> >>
> >> There's a good one. Especially when the humidity is very low, and the
> >> peanuts are all broken up in pieces!
> >
> >
> > Low humidity is rarely a problem in Florida. :(
> >
> >
> > --
> > You can't fix stupid. You can't even put a band-aid on it, because it's
> > Teflon coated.
>
> Yeah.. One time I was going to paint something. The can of spray paint said
> to only use it in 50% or less humidity. I laughed when I read that and
> thought there must be less than 20 days a year that would have low enough
> humidity to paint this thing..

That's when you dig out the heat lamps to dry the surface, before you
paint. :)

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

== 4 of 10 ==
Date: Sun, Jan 23 2011 9:18 pm
From: Jeff Liebermann

On Fri, 21 Jan 2011 04:37:26 -0800 (PST), b
<reverend_rogers@yahoo.com> wrote:

>Pet hates: excessive amounts of screws holding covers of TVs etc.
>together. this seems to have got worse with flat panels.Often you
>spend as much /more time assembling and re-asembling than the repair!
>-B

Screws are fine. I can live with having too many screws because half
of them are usually stripped out and the remainder hold things
together. What bugs me are snap together clamshell cases, such as LCD
monitors and TV's, where you have to remove a mess of screws *AND* pry
the case apart. While snap together plastic is probably easier to
assemble because it doesn't require much fixturing to position the
robotic screwdriver, it does suggest that the case was never intended
to be opened or the unit repaired.

I recently repaired a Yamaha P70 electric piano. I didn't count, but
I'll guess about 60 large "sheet metal" type screws holding it
together. I don't use an electric screwdriver, but this is one time
that I wish I owned one. Even with switching hands, my hands ached
after I as done. The problem with such "sheet metal" screws is that
they offer high frictional resistance on every turn, while more
conventional screw threads, only offer high resistance when tight (or
smeared with thread lock).

My guess is the large number of screws was to prevent mechanical
resonances in the plastic case or to keep them from falling out from
vibrations. Still, metal thread inserts, screw threads, and steel nut
plates, would have been much easier to handle.

On the silicon grease front, I agree with most of the comments. Thin
works much better than globs of silicon grease. One should remember
that the purpose of silicon grease is NOT to bridge gaps. It's to
fill in the surface roughness, groves, and crevasses. Most of the
heat transfer is metal to metal contact, not through the silicon
grease.

In a past life, I used to design marine radios. The problem was that
the power xsistor packages of the day (1970's) were generally thermal
disasters. Either there was insufficient contact area to obtain
sufficiently low thermal resistance, or they were not flat. I solved
the first by building pyramid like structures of copper washers to act
as a heat spreader. I solved the latter by polishing the mounting
base of the power transistors on fine emery cloth. I hated to polish
away the gold plating, but that's what it took to get the heat out. I
made numerous tests and measurements trying to determine the optimum
amount of silicon grease, and eventually concluded that ultra thin is
best. Instructions were to smear a tiny amount onto the area, and
then wipe ALL of it off with a plastic scraper. What remained was
silicon grease in the remaining surface roughness, which was all that
was necessary.

I recently repaired an IFR-1500 service monitor. The power supply
section was intermittent. The 0.062 aluminum power supply case, was
butted up against the large aluminum heat sink that covered the entire
rear panel. In between was a huge amount of silicon grease. The
sandwich was held together by two large 10-24 screws, which probably
explains the silicon grease overdose. Two screws is not going to bend
the aluminum case so that it lays flat. So they tried to fill in the
lack of flatness with silicon grease. That doesn't work.

It took me considerable effort and alcohol to clean up the mess, but I
still managed to get it all over everything on the bench. After the
repair (large copper wires on torroids were not soldered properly), I
reassembled it with only a little silicon grease around the two large
screws, and left the rest to it's own devices. Works fine with no
obvious overheating (checked with an IR thermometer and thermocouple
probe). My guess is all that silicon grease did nothing useful.

--
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

== 5 of 10 ==
Date: Sun, Jan 23 2011 9:36 pm
From: Jeff Liebermann

On Sat, 22 Jan 2011 01:50:24 -0000, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>"Mark Zacharias" <mark_zacharias@sbcglobal.net> wrote in message
>news:4d381c8b$0$19215$c3e8da3$aae71a0a@news.astraweb.com...
>> People begging me to work on stuff which I used to turn away, but now have
>> to take in because business is slow.
>> Mark Z.

>Yep. Amen to that one ...
>Arfa

Not much of a change here. Most of my work is fixing computers,
networks, and printers. That part of the business has decreased
substantially. However, I've always done 2-way radio, audio,
electronic music, cell phones, home theater, monitors, power tools,
test equipment, HP calculators, kids toys, and whatever the customers
need fixing. The only recent change is that I'm doing less computers
and more of the other stuff. However, I don't think it has much to do
with the global economic situation. The preference of the American
consumer for cheap junk, usually made in China, has displaced most of
the higher reliability, but also higher priced, better quality
products. After discovering that the cheap junk replacement is no
better than the original cheap junk device that had failed, they start
looking to me to help them keep the cheap junk alive. It's possible,
but since they'll often pay more than the device is worth just so that
they don't have to deal with the vendor, I can make money on such
repairs. Often, nothing more than a thorough cleaning is all that's
required. I also fix bicycles, chain saws, and optics, but since I
don't really know what I'm doing, I avoid major challenges. If I had
concentrated solely on computer repair, I would have been in serious
financial trouble, but by offering my services to fix almost anything
(i.e. diversification), a drop in one area, won't wipe out the
business.

Oh, there is one area that I won't do any more. I'm no longer able to
the construction work necessary to run CAT5 all over a building. I
contract that out to younger and more suicidal kids, who are usually
grateful for the work and money.

--
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

== 6 of 10 ==
Date: Sun, Jan 23 2011 9:52 pm
From: John Robertson

Arfa Daily wrote:
>
>
> "William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
> news:ih7bqe$ajf$1@news.eternal-september.org...
>>> I once got in a lot of trouble with my boss when I was young and worked
>> for
>>> a U.S. based company. At that time, I didn't understand that there was a
>> big
>>> difference between British 'tongue-in-cheek' humour, and the much more
>>> direct U.S. type. I was talking on the phone to one of the designers
>>> of a
>>> piece of equipment that we sold here in the UK, and asked the guy if he
>>> could arrange to send me some screws for the cabinet, as they were a
>> thread
>>> that we didn't readily get over here. He asked if I knew exactly what
>>> size
>>> they were so I replied, quick as a flash, thinking that I was being
>>> funny,
>>> "I guess that they are round about 3/16ths APF." "What's APF ?" the guy
>>> asked. "American Piss Fit", said I ...
>>
>>> Stony silence on the phone. Half an hour later, I was summoned to the
>> boss's
>>> office. Apparently, the guy had been really offended by this, thinking
>> that
>>> it was a slur on what he considered to be good American engineering, and
>> had
>>> called my boss to complain about me. Just goes to show how easily
>>> offence
>>> can be caused between nations, even when they speak what's basically the
>>> same language ... :-)
>>
>> It's hard /not/ to interpret such a description as an intentional
>> insult. I
>> can't imagine what it actually means -- in any innocuous sense, anyway.
>>
>>
>
> There ya go then ! Anyone from the UK would see it as a quick-fire
> throw-away line, and would laugh at it. It's sort of intended to be
> 'barbed', but not in a malicious way. It's a very hard to describe form
> of humour that is quite prevalent over here.
>
> Arfa

We'ed only be confused in Canada. We have to deal with both UK and US
humour....

John ;-#)#

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

== 7 of 10 ==
Date: Sun, Jan 23 2011 10:00 pm
From: John Robertson

Michael Kennedy wrote:
> "David Nebenzahl" <nobody@but.us.chickens> wrote in message
> news:4d3be2e9$0$4737$822641b3@news.adtechcomputers.com...
>> On 1/23/2011 12:02 AM Smitty Two spake thus:
>>
>>> In article <4d3b9067$0$2378$822641b3@news.adtechcomputers.com>,
>>> David Nebenzahl <nobody@but.us.chickens> wrote:
>>>
>>>> But beware: up here in the Beige Area, where we like to think we're so
>>>> much superior to our SoCal cousins, we never use the article, saying
>>>> instead "take 80 to get to Berkeley" or "take 101 to 280 to 17 to get
>>>> down to Santa Cruz". (One can easily spot newcomers to San Francisco who
>>>> refer to "the 80" or "the 101". That's just SO wrong!)
>>> I don't think Arfa is going to "blend" whether he uses your terminology
>>> or not, and I doubt that's his objective. But you wrote an awful lot of
>>> words without using "freeway," which is what we call the 101 here, and is
>>> the most common word for "interstate highway" throughout the midwest, as
>>> well.
>> Yup, my bad; thought of it shortly after clicking "Send", of course.
>>
>>> BTW, everyone I know in LA doesn't use numbers at all, but names that are
>>> meaningless to outsiders even if they have a map: "Ventura freeway,"
>>> "Hollywood freeway," "Pasadena freeway," etc.
>> Forgot about that too. Our freeways also have names, but they're (mostly)
>> unused: one occasionally hears 880 called "the Nimitz" or 80 "the
>> Eastshore", but more often not.
>>
>> Then of course there's Johnny Carson's old favorite, the "Slauson Cutoff"
>> ...
>>
>>
>> --
>> Comment on quaint Usenet customs, from Usenet:
>>
>> To me, the *plonk...* reminds me of the old man at the public hearing
>> who stands to make his point, then removes his hearing aid as a sign
>> that he is not going to hear any rebuttals.
>
>
>
> In Florida many people call the "Interstate Highways" by its number.. For
> example Interstate 4 is just I4. Other examples are I95 I75.. But it is
> perfectly normal to hear take 75 or Take 95, although take 4 seems a bit
> rare.
>
> We have a turnpike as well. It refers to the first large toll road in
> Florida.. (I believe it was the first.) Because it's officail name is The
> Florida Turnpike or The Ronald Regan Turnpike.. It has 2 names..
>
> Anyhow, I have wasted enough of your time now..
>
> Mike
>
>

Here in BC, Canada and (it appears) the Pacific Northwest states the US
highways are called Ixx - I5 being the main north-south one.

John :-#)#

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

== 8 of 10 ==
Date: Sun, Jan 23 2011 10:01 pm
From: Jeff Liebermann

On Sat, 22 Jan 2011 18:21:21 -0800, David Nebenzahl
<nobody@but.us.chickens> wrote:

>But beware: up here in the Beige Area, where we like to think we're so
>much superior to our SoCal cousins, we never use the article, saying
>instead "take 80 to get to Berkeley" or "take 101 to 280 to 17 to get
>down to Santa Cruz". (One can easily spot newcomers to San Francisco who
>refer to "the 80" or "the 101". That's just SO wrong!)

Ahem. I beg to differ slightly. In the People's Republic of Santa
Cruz, it's called "Highway 9", "Highway 17", and "Highway 1". They're
never referred to by their correct name of "US Route 9", "State Route
17", and "Calif State Route 1".

In Smog Angeles, Hwy 1 is called "Pacific Coast Highway", State Route
90 is the "Richard M. Nixon Freeway", and Interstate 5 is called the
"San Diego Freeway".

When I lived over the hill in San Jose in the late 1970's, the
numerical designations were rarely used. Interstate 880 was called
"the Nimitz". These days, nobody remembers Admiral Nimitz so it has
become "880".

Caltrans seems to be making a concerted and expensive effort to add to
the confusion by numbering all the freeway exits and onramps.
Unfortunately, they didn't plan it very well, so some of the numbers
are already out of sequence and there are postfixes such as "Exit
11c". I have yet to hear anyone refer to a specifically named exit by
its numerical equivalent.

When one visits the People's Republic of Santa Cruz, the point of
entry is what is called "the fish-hook" because of a 270 degree tight
turn. It's been greatly improved by an expensive rebuild 4 years ago,
but it still offers a fair approximation of a roller coaster ride:
<http://we.got.net/~mapman/streets/SantaCruz/Fishhook/fishhook.html>
My office is adjacent to this abomination. I would estimate we lose
one large truck to the tight turns every 2 weeks.

--
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

== 9 of 10 ==
Date: Sun, Jan 23 2011 10:05 pm
From: David Nebenzahl

On 1/23/2011 10:00 PM John Robertson spake thus:

> Michael Kennedy wrote:
>
>> In Florida many people call the "Interstate Highways" by its number.. For
>> example Interstate 4 is just I4. Other examples are I95 I75.. But it is
>> perfectly normal to hear take 75 or Take 95, although take 4 seems a bit
>> rare.
>
> Here in BC, Canada and (it appears) the Pacific Northwest states the US
> highways are called Ixx - I5 being the main north-south one.

Well, they're actually called that everywhere in the US, at least
officially and on maps. But what do *people* in that region actually
call them? I thought that's what we were talking about here.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 10 of 10 ==
Date: Mon, Jan 24 2011 12:45 am
From: "N_Cook"

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:f21qj69nksr8pclj13qq54ukv07uhrtb8k@4ax.com...
> On Fri, 21 Jan 2011 04:37:26 -0800 (PST), b
> <reverend_rogers@yahoo.com> wrote:
>
> >Pet hates: excessive amounts of screws holding covers of TVs etc.
> >together. this seems to have got worse with flat panels.Often you
> >spend as much /more time assembling and re-asembling than the repair!
> >-B
>
> Screws are fine. I can live with having too many screws because half
> of them are usually stripped out and the remainder hold things
> together. What bugs me are snap together clamshell cases, such as LCD
> monitors and TV's, where you have to remove a mess of screws *AND* pry
> the case apart. While snap together plastic is probably easier to
> assemble because it doesn't require much fixturing to position the
> robotic screwdriver, it does suggest that the case was never intended
> to be opened or the unit repaired.
>
> I recently repaired a Yamaha P70 electric piano. I didn't count, but
> I'll guess about 60 large "sheet metal" type screws holding it
> together. I don't use an electric screwdriver, but this is one time
> that I wish I owned one. Even with switching hands, my hands ached
> after I as done. The problem with such "sheet metal" screws is that
> they offer high frictional resistance on every turn, while more
> conventional screw threads, only offer high resistance when tight (or
> smeared with thread lock).
>
> My guess is the large number of screws was to prevent mechanical
> resonances in the plastic case or to keep them from falling out from
> vibrations. Still, metal thread inserts, screw threads, and steel nut
> plates, would have been much easier to handle.
>
> On the silicon grease front, I agree with most of the comments. Thin
> works much better than globs of silicon grease. One should remember
> that the purpose of silicon grease is NOT to bridge gaps. It's to
> fill in the surface roughness, groves, and crevasses. Most of the
> heat transfer is metal to metal contact, not through the silicon
> grease.
>
> In a past life, I used to design marine radios. The problem was that
> the power xsistor packages of the day (1970's) were generally thermal
> disasters. Either there was insufficient contact area to obtain
> sufficiently low thermal resistance, or they were not flat. I solved
> the first by building pyramid like structures of copper washers to act
> as a heat spreader. I solved the latter by polishing the mounting
> base of the power transistors on fine emery cloth. I hated to polish
> away the gold plating, but that's what it took to get the heat out. I
> made numerous tests and measurements trying to determine the optimum
> amount of silicon grease, and eventually concluded that ultra thin is
> best. Instructions were to smear a tiny amount onto the area, and
> then wipe ALL of it off with a plastic scraper. What remained was
> silicon grease in the remaining surface roughness, which was all that
> was necessary.
>
> I recently repaired an IFR-1500 service monitor. The power supply
> section was intermittent. The 0.062 aluminum power supply case, was
> butted up against the large aluminum heat sink that covered the entire
> rear panel. In between was a huge amount of silicon grease. The
> sandwich was held together by two large 10-24 screws, which probably
> explains the silicon grease overdose. Two screws is not going to bend
> the aluminum case so that it lays flat. So they tried to fill in the
> lack of flatness with silicon grease. That doesn't work.
>
> It took me considerable effort and alcohol to clean up the mess, but I
> still managed to get it all over everything on the bench. After the
> repair (large copper wires on torroids were not soldered properly), I
> reassembled it with only a little silicon grease around the two large
> screws, and left the rest to it's own devices. Works fine with no
> obvious overheating (checked with an IR thermometer and thermocouple
> probe). My guess is all that silicon grease did nothing useful.
>
>
> --
> Jeff Liebermann jeffl@cruzio.com
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com

I suspect we are as engineers are just as likely to be mislead by
manufacturer's claims as joe public and general ads. I could not convince
myself that silipads were better than mica (no patents so litterally dirt
cheap) - so experiment called for. These days I own a matchbox size remote
IR pyrometer and would use that to compare device body temps in before and
after situations , not fingertips

Mica versus Silicone pad insulators
I was not convinced that for an existing used amp with 4x TOP66 power output
devices that the silipads were better than mica.
Each of the 4 white insulating pads had shrunk about 5mm at the tops
(hottest)
compared to bottoms , ruffling the original outer edges, heat damage ?.
I'm wondering if they can chemically change over time and/or excessive
temperature , downgrading to be more of a thermal insulator.
They are not discoloured or hardened or anything different in the
ex-compressed area by sight or flexing, just permanently deformed , the
ruffling is permanent.
I replaced all 4 with mica and thin films of thermal grease.
Before doing so I powered up the amp with 400 Hz continuous sine giving 20
watts in a dummy load. No fan cooling for this amp, just
convection/radiation.
Laid a brass barrel protected thermometer on the heatsink and took
measurements. Stabilised at 33 deg C over ambient after 50 minutes.
Replaced with mica and redid the load test.
For same ambient , same testing position/attitude, power in load etc it now
took 30 minutes to stabilise at plus 32 deg C over ambient.
More graphically , but less scientific, - the finger test.
After half an hour of heating with the mica setup I could hold a fingertip
on each tranny for about 5 seconds before finding it uncomfortable.
Previously half a second of fingertip touch was enough.
I think I will rely on the evidence of my own observations and not
performance tables produced by the manufacturer's with an obvious vested
interest.
I've no reason to believe the original silipads had aged, been affected by
WD40 or anything.
I will assume they are , all manufacturers, all generically bad until a
similar personally conducted experiment, in a real situation, proves to me
to be otherwise.

==============================================================================
TOPIC: Nickel plated polyimide--where to get?
http://groups.google.com/group/sci.electronics.repair/t/8bee83d05dbdcb50?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 24 2011 12:53 am
From: Uwe Hercksen

William Sommerwerck schrieb:

> Wouldn't it be possible to make the polyimide conductive by rubbing graphite
> into its surface ("The Audio Amateur" had at least one article about
> home-made electrostatic speakers that showed how to do this with Mylar),
> then plate it?

Hello,

it will be possible to get a nickel layer on the polyiimide if you start
galvanic plating with very low currents and the gradually increase it.
But the problem is the poor fixation of the nickel layer to the
polyimide. The normal pcb material uses a special glue for the fixation
of the copper foil to the base material.

Bye

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