sci.electronics.repair@googlegroups.com

Today's topics:

* LORAN C - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/73c2d1e0342e191b?hl=en
* Yet another bulging-capacitors replacement - 11 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/3ec97de65fce9bb3?hl=en
* Technics SA-310 Receiver Fixed! - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/266f00b3a43b6910?hl=en

==============================================================================
TOPIC: LORAN C
http://groups.google.com/group/sci.electronics.repair/t/73c2d1e0342e191b?hl=en
==============================================================================

== 1 of 2 ==
Date: Wed, Sep 1 2010 10:41 am
From: Jeff Liebermann

On Wed, 1 Sep 2010 10:30:59 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:

>I hope LW RDF is still going , I liked the morse ident feature and its
>simplicity. I doubt , over some distance , it is any less accurate than
>Loran and no hyperbolic plots to deal with

Yep. They're still alive and well. I still have a Taiho automagic
mechanically rotating LW RDF that I use for demonstrations. It's fun
to watch the loop seek and maybe point. Some of the LW beacon
stations are sending DGPS which have largely been replaced by WAAS
technology. Hearing LW beacons more than a few miles from shore is
tricky without a big antenna. You would probably be more successful
using AM, FM, and TV stations for coastline navigation, than using the
few LW stations.
<http://www.beaconworld.fotopic.net/list_collections.php>

Incidentally, the big problem with Loran-C was that it really didn't
work more than about 100 miles offshore. That limitation sold
considerable number of (pre-GPS) Transit and Omega systems as "backup"
for Loran-C. At least they worked in mid ocean. Incidentally, I
still have my Tamaya sextant and a Magnavox TRANSIT receiver in
storage.

If you want to do it thyself, it's possible to do 2D TRANSIT(NAVSAT)
doppler navigation if you can hear some LEO satellites, know the
Keplarian elements, and can accurately measure and record the doppler
shift as it passes overhead, using triangulation and trilateration.
The NIMS system may still be alive on 149.985 and 399.970 with
telemetry on 136.650 MHz although Keps appear to be lacking:
<http://www.zarya.info/Frequencies/Frequencies150.php>
Have your spherical geometry reference book handy. I've never
actually tried it, but it should be possible:
<http://en.wikipedia.org/wiki/Trilateration>

The Origins of GPS:
<http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-1-9890>
<http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-2-fighting-survive-10010>

--
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 2 ==
Date: Wed, Sep 1 2010 11:44 am
From: zekfrivo@zekfrivolous.com (GregS)

In article <mu0t761s85hgq8f1vnv3vhelfppfc43af4@4ax.com>, Jeff Liebermann <jeffl@cruzio.com> wrote:
>On Wed, 1 Sep 2010 10:30:59 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:
>
>>I hope LW RDF is still going , I liked the morse ident feature and its
>>simplicity. I doubt , over some distance , it is any less accurate than
>>Loran and no hyperbolic plots to deal with
>
>Yep. They're still alive and well. I still have a Taiho automagic
>mechanically rotating LW RDF that I use for demonstrations. It's fun
>to watch the loop seek and maybe point. Some of the LW beacon
>stations are sending DGPS which have largely been replaced by WAAS
>technology. Hearing LW beacons more than a few miles from shore is
>tricky without a big antenna. You would probably be more successful
>using AM, FM, and TV stations for coastline navigation, than using the
>few LW stations.
><http://www.beaconworld.fotopic.net/list_collections.php>

If we got a big solar storm, and most or all satellites got knocked out,
along with ground power, the beacons may be the only route home.

I remember having to record Loran D, just another experimental site.

>Incidentally, the big problem with Loran-C was that it really didn't
>work more than about 100 miles offshore. That limitation sold
>considerable number of (pre-GPS) Transit and Omega systems as "backup"
>for Loran-C. At least they worked in mid ocean. Incidentally, I
>still have my Tamaya sextant and a Magnavox TRANSIT receiver in
>storage.
>
>If you want to do it thyself, it's possible to do 2D TRANSIT(NAVSAT)
>doppler navigation if you can hear some LEO satellites, know the
>Keplarian elements, and can accurately measure and record the doppler
>shift as it passes overhead, using triangulation and trilateration.
>The NIMS system may still be alive on 149.985 and 399.970 with
>telemetry on 136.650 MHz although Keps appear to be lacking:
><http://www.zarya.info/Frequencies/Frequencies150.php>
>Have your spherical geometry reference book handy. I've never
>actually tried it, but it should be possible:
><http://en.wikipedia.org/wiki/Trilateration>
>
>The Origins of GPS:
><http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-1-9
>890>
><http://www.gpsworld.com/gnss-system/gps-modernization/the-origins-gps-part-2-f
>ighting-survive-10010>
>
>

==============================================================================
TOPIC: Yet another bulging-capacitors replacement
http://groups.google.com/group/sci.electronics.repair/t/3ec97de65fce9bb3?hl=en
==============================================================================

== 1 of 11 ==
Date: Wed, Sep 1 2010 1:55 pm
From: "Michael A. Terrell"

Arfa Daily wrote:
>
> "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
> news:m5ednfqzQtE_8ePRnZ2dnUVZ_qWdnZ2d@earthlink.com...
> ?
> ? Arfa Daily wrote:
> ??
> ?? Well Jim, that was why I used the word "potentially", but judging by the
> ?? size of the pins used to couple the power supply's output into the
> ?? board -
> ?? if you've been following the thread, you will recall that I previously
> ?? described them as being of the size you would find on the line cord for a
> ?? kettle - then I wouldn't say that there was too much in the way of
> ?? reserve.
> ?
> ? "The size you would find on the line cord for a kettle" doesn't have
> ? much meaning in the US. :)
>
> Why is that ? You have electric kettles in your kitchens - I've used them.

I've never seen one. Even Coffee pots are rare these days.

> Or don't you call them kettles ?. OK, anyway, if it's a better description,
> the size of the round ground pin on a line cord that has a three pin plug.
> Is that more meaningful ? 3/16" diameter maybe ? 4mm ?

3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
much current do those kettles draw?

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

== 2 of 11 ==
Date: Wed, Sep 1 2010 2:15 pm
From: Meat Plow

On Wed, 01 Sep 2010 16:55:34 -0400, Michael A. Terrell wrote:

> Arfa Daily wrote:
>>
>> "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
>> news:m5ednfqzQtE_8ePRnZ2dnUVZ_qWdnZ2d@earthlink.com... ?
>> ? Arfa Daily wrote:
>> ??
>> ?? Well Jim, that was why I used the word "potentially", but judging by
>> the ?? size of the pins used to couple the power supply's output into
>> the ?? board -
>> ?? if you've been following the thread, you will recall that I
>> previously ?? described them as being of the size you would find on the
>> line cord for a ?? kettle - then I wouldn't say that there was too much
>> in the way of ?? reserve.
>> ?
>> ? "The size you would find on the line cord for a kettle" doesn't have
>> ? much meaning in the US. :)
>>
>> Why is that ? You have electric kettles in your kitchens - I've used
>> them.
>
>
> I've never seen one. Even Coffee pots are rare these days.
>
>
>> Or don't you call them kettles ?. OK, anyway, if it's a better
>> description, the size of the round ground pin on a line cord that has a
>> three pin plug. Is that more meaningful ? 3/16" diameter maybe ? 4mm ?
>
>
> 3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
> much current do those kettles draw?

Half what a US kettle would draw?

--
Live Fast, Die Young and Leave a Pretty Corpse

== 3 of 11 ==
Date: Wed, Sep 1 2010 5:24 pm
From: Archon

On 9/1/2010 5:15 PM, Meat Plow wrote:
> On Wed, 01 Sep 2010 16:55:34 -0400, Michael A. Terrell wrote:
>
>> Arfa Daily wrote:
>>>
>>> "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
>>> news:m5ednfqzQtE_8ePRnZ2dnUVZ_qWdnZ2d@earthlink.com... ?
>>> ? Arfa Daily wrote:
>>> ??
>>> ?? Well Jim, that was why I used the word "potentially", but judging by
>>> the ?? size of the pins used to couple the power supply's output into
>>> the ?? board -
>>> ?? if you've been following the thread, you will recall that I
>>> previously ?? described them as being of the size you would find on the
>>> line cord for a ?? kettle - then I wouldn't say that there was too much
>>> in the way of ?? reserve.
>>> ?
>>> ? "The size you would find on the line cord for a kettle" doesn't have
>>> ? much meaning in the US. :)
>>>
>>> Why is that ? You have electric kettles in your kitchens - I've used
>>> them.
>>
>>
>> I've never seen one. Even Coffee pots are rare these days.
>>
>>
>>> Or don't you call them kettles ?. OK, anyway, if it's a better
>>> description, the size of the round ground pin on a line cord that has a
>>> three pin plug. Is that more meaningful ? 3/16" diameter maybe ? 4mm ?
>>
>>
>> 3/16" is between AWG 5& AWG 4. 4 mm is between AWG 7& AWG 6. How
>> much current do those kettles draw?
>
> Half what a US kettle would draw?
>
>
>
A good British 240Vac kettle will take 3KW, yes 3KW. No waiting 10
minutes for the lousy thing to boil.

JC

== 4 of 11 ==
Date: Wed, Sep 1 2010 6:29 pm
From: "Arfa Daily"

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:Jo2dnfqSRvF9IOPRnZ2dnUVZ_sidnZ2d@earthlink.com...
>
> Arfa Daily wrote:
>>
>> "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
>> news:m5ednfqzQtE_8ePRnZ2dnUVZ_qWdnZ2d@earthlink.com...
>> ?
>> ? Arfa Daily wrote:
>> ??
>> ?? Well Jim, that was why I used the word "potentially", but judging by
>> the
>> ?? size of the pins used to couple the power supply's output into the
>> ?? board -
>> ?? if you've been following the thread, you will recall that I previously
>> ?? described them as being of the size you would find on the line cord
>> for a
>> ?? kettle - then I wouldn't say that there was too much in the way of
>> ?? reserve.
>> ?
>> ? "The size you would find on the line cord for a kettle" doesn't have
>> ? much meaning in the US. :)
>>
>> Why is that ? You have electric kettles in your kitchens - I've used
>> them.
>
>
> I've never seen one. Even Coffee pots are rare these days.
>
>
>> Or don't you call them kettles ?. OK, anyway, if it's a better
>> description,
>> the size of the round ground pin on a line cord that has a three pin
>> plug.
>> Is that more meaningful ? 3/16" diameter maybe ? 4mm ?
>
>
> 3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
> much current do those kettles draw?
>
>
> --

Typical UK kettle is 2 - 3kW so 8 to 12 amps or thereabouts. Now, I'm really
confused that you say that you've never seen one. How do you boil water for
a cup of tea, or a cup of instant coffee ? Whenever I come to Florida, I
stay in a private rental home, and although some have had a kettle that
heats from a ring on the cooker, I'm sure that I have also stayed in homes
that had an electric version. Or maybe I'm mistaken on this ? Perhaps with
your line power at only 110v at a non 3 phase outlet, the current levels are
impractical with an element powerful enough to heat the water in short
order. Here, every home - and I really mean *every home* - has one. It is a
known problem for the electricity grid controllers, when TV ads come on in
the middle of the popular soaps. Short term demand goes through the roof, as
everyone rushes out to make a cup of tea or coffee, at the same time. The
controllers genuinely have to know the advert schedules in the TV
programmes, and factor this into their load shedding operations.

Arfa

== 5 of 11 ==
Date: Wed, Sep 1 2010 6:41 pm
From: "Arfa Daily"

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:o4vs76df7mcfo4o21nte5ok0l1b2g490bg@4ax.com...
> On Wed, 1 Sep 2010 02:40:53 +0100, "Arfa Daily"
> <arfa.daily@ntlworld.com> wrote:
>
>>All of the processing power is in those two BGAs Jeff.
> (...)
>
> Thanks for the details. I really don't know anything about such
> dedicated game machines. I just assumed that all such machines used
> common processors to make development easier.
>
>>That's a LOT of processing power, needing a lot of amps to perform ...
>
> I found the Kill-o-watt meter and stuffed it in line with my Dell
> Optiplex 960 (E8500 3.2Ghz). 43 watts at idle, 70 watts max when
> playing a DVD (not including LCD monitor). Speedfan 4.40 says 31C for
> both CPU cores after about an hour. The one large fan is barely
> spinning and very quiet (which is why I bought this one). When I set
> the fan to run full speed, it's quite loud.
>
>>The fan on these things *is* large, as is the heatsinking assembly, and
>>when
>>the processor finally decides to ramp the fan up, it sounds like a vacuum
>>cleaner. For this reason, at idle they tend to run it at below what I
>>would
>>consider a 'sensible' minimum, exacerbating the thermal stresses on the
>>chips, their (lead-free) soldering, and the board to which they are
>>attached.
>
> Well, theory suggests that the life of a semiconductor device is
> greatly affected by the number of thermal cycles it experiences
> (thermal fatigue). I don't know if this also applies to CPU's or
> whatever is in those BGA chips (FPGA/GPU?), but might be something
> else to worry about. I would guess(tm) that the large aluminum heat
> sink would moderate any abrupt changes in temperature, thus making it
> less of a concern. However, that might not be the case for the solder
> balls supporting the BGA.
>
>
>
> --
> Jeff Liebermann jeffl@cruzio.com

The soldering under the BGAs letting go, is the commonest problem with both
the Sony PS3 ( "yellow light of death") and the X-Box 360 ("red ring of
death")

Those names for the conditions refer to the behaviour of the front panel
indicator LEDs when the faults that result, show themselves.

I am quite convinced that the slow running of the fan at idle, is a major
contributory factor in the failing of the BGA soldering.

Arfa

== 6 of 11 ==
Date: Wed, Sep 1 2010 7:31 pm
From: Mike Tomlinson

In article <ebug76lk13plippid57h6q6vacu8ve4om9@4ax.com>, Jeff Liebermann
<jeffl@cruzio.com> writes

>I don't believe it. The winner of the power hogging consumer CPU
>contest was the DEC/Intel Alpha 21364 (EV79):

I herded a fleet of 21264s (AlphaServer DS10) for a while. Impressive
heatsinks in those. One is still in use today.

--
(\__/)
(='.'=)
(")_(")

== 7 of 11 ==
Date: Wed, Sep 1 2010 7:26 pm
From: Mike Tomlinson

In article <BDDdo.2319$3p1.124@hurricane>, Arfa Daily
<arfa.daily@ntlworld.com> writes

>Just as a matter of interest Meat, what is your preferred brand and type of
>heatsink goop when working with these very high power processors?

I'd recommend Arctic Silver.

> I have always
>resisted using this stuff, because it's so messy, and so hard to remove
>unless you use the complementary cleaner

nah, standard IPA works fine. The trick is to use clean tissue wetted
with IPA, wiping just once or twice then replacing with a fresh piece,
repeating until the CPU is clean. If you go back with used tissue, you
just spread the AS about more.

If it makes that much mess, you're using too much. See the application
tips on the AS website. You literally only need a half-a-grain-of-rice
sized blob in the centre of the CPU heat spreader, it'll spread out by
itself with pressure from the heatsink. Note AS say it can take a few
heat/cool cycles to become fully effective, and indeed this is what I
have found.

>, but if it really is that much more
>effective

It is. A colleague at work was struggling to cool a CCD (a big one!)
without having to resort to cryogenic cooling. He was experimenting
with a Peltier cooler and unable to transfer heat away from the CCD fast
enough. I suggested he try replacing the standard white goop with AS
and he was astonished at the massive improvement in heat transfer.

--
(\__/)
(='.'=)
(")_(")

== 8 of 11 ==
Date: Wed, Sep 1 2010 7:41 pm
From: Mike Tomlinson

In article <Faifo.2289$1F2.1572@newsfe21.ams2>, Arfa Daily
<arfa.daily@ntlworld.com> writes

> exacerbating the thermal stresses on the
>chips, their (lead-free) soldering, and the board to which they are
>attached.

Which is what caused the 'red ring of death' on Microsoft's Xbox.

--
(\__/)
(='.'=)
(")_(")

== 9 of 11 ==
Date: Wed, Sep 1 2010 7:36 pm
From: Mike Tomlinson

In article <mzvfo.28576$zA5.13324@newsfe16.ams2>, Arfa Daily
<arfa.daily@ntlworld.com> writes

>Why is that ? You have electric kettles in your kitchens - I've used them.

They do, they just take three times longer to boil. They're nowhere
near as ubiquitous in American kitchens as they are in the UK.

--
(\__/)
(='.'=)
(")_(")

== 10 of 11 ==
Date: Wed, Sep 1 2010 7:38 pm
From: Mike Tomlinson

In article <Jo2dnfqSRvF9IOPRnZ2dnUVZ_sidnZ2d@earthlink.com>, Michael A.
Terrell <mike.terrell@earthlink.net> writes

> 3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
>much current do those kettles draw?

2kW and 3kW kettles are common. 2kW is ~8.3A, 3kW is ~12.5A. UK plugs
and sockets (=receptacles over the pond) are rated for 13A.

--
(\__/)
(='.'=)
(")_(")

== 11 of 11 ==
Date: Wed, Sep 1 2010 11:59 pm
From: "Michael A. Terrell"

Arfa Daily wrote:
>
> "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
> news:Jo2dnfqSRvF9IOPRnZ2dnUVZ_sidnZ2d@earthlink.com...
> ?
> ? Arfa Daily wrote:
> ??
> ?? "Michael A. Terrell" ?mike.terrell@earthlink.net? wrote in message
> ?? news:m5ednfqzQtE_8ePRnZ2dnUVZ_qWdnZ2d@earthlink.com...
> ?? ?
> ?? ? Arfa Daily wrote:
> ?? ??
> ?? ?? Well Jim, that was why I used the word "potentially", but judging by
> ?? the
> ?? ?? size of the pins used to couple the power supply's output into the
> ?? ?? board -
> ?? ?? if you've been following the thread, you will recall that I previously
> ?? ?? described them as being of the size you would find on the line cord
> ?? for a
> ?? ?? kettle - then I wouldn't say that there was too much in the way of
> ?? ?? reserve.
> ?? ?
> ?? ? "The size you would find on the line cord for a kettle" doesn't have
> ?? ? much meaning in the US. :)
> ??
> ?? Why is that ? You have electric kettles in your kitchens - I've used
> ?? them.
> ?
> ?
> ? I've never seen one. Even Coffee pots are rare these days.
> ?
> ?
> ?? Or don't you call them kettles ?. OK, anyway, if it's a better
> ?? description,
> ?? the size of the round ground pin on a line cord that has a three pin
> ?? plug.
> ?? Is that more meaningful ? 3/16" diameter maybe ? 4mm ?
> ?
> ?
> ? 3/16" is between AWG 5 ? AWG 4. 4 mm is between AWG 7 ? AWG 6. How
> ? much current do those kettles draw?
> ?
> ?
> ? --
>
> Typical UK kettle is 2 - 3kW so 8 to 12 amps or thereabouts. Now, I'm really
> confused that you say that you've never seen one. How do you boil water for
> a cup of tea, or a cup of instant coffee?

On the gas or electric stove. A lot of people heat the water in a
microwave. Fast and efficient.

> Whenever I come to Florida, I
> stay in a private rental home, and although some have had a kettle that
> heats from a ring on the cooker, I'm sure that I have also stayed in homes
> that had an electric version. Or maybe I'm mistaken on this? Perhaps with
> your line power at only 110v at a non 3 phase outlet, the current levels are
> impractical with an element powerful enough to heat the water in short
> order. Here, every home - and I really mean *every home* - has one. It is a
> known problem for the electricity grid controllers, when TV ads come on in
> the middle of the popular soaps. Short term demand goes through the roof, as
> everyone rushes out to make a cup of tea or coffee, at the same time. The
> controllers genuinely have to know the advert schedules in the TV
> programmes, and factor this into their load shedding operations.

The same thing with water demand when people rush to the bathroom
during a commercial. :)

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

==============================================================================
TOPIC: Technics SA-310 Receiver Fixed!
http://groups.google.com/group/sci.electronics.repair/t/266f00b3a43b6910?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 1 2010 9:39 pm
From: "William R. Walsh"

A follow up to my follow up...one thing that I've noticed is how hot the
various "Computer Drive" receivers run even when operating normally. So I
found my IR non-contact thermometer and had a look at the newly repaired
SA-310.

At idle for around 20 minutes, the temperature of the heatsink had risen to
130 degrees Fahrenheit (54 degrees Celsius)! And the unit was just *idling*.
The hybrid's internals are probably a good ten degrees hotter still. Call me
picky, but that is not what I'd call the recipe for semiconductor longevity!
Ouch! (Just how did the last hybrid--presumably the original--manage to live
so long?)

By comparison, the Class AB SA-120 (with its identical power rating) idles
around 88-90 degrees F after being on for a while. Its STK module also has a
much smaller heatsink.

For now I have made a "contraption" consisting of a DC muffin fan affixed to
the bottom of the SA-310 using bubble wrap on the corners to stop the case
from vibrating. With this setup, and two books at each end of the receiver
to give the fan clearance, the temperature never gets above 105 degrees F
even with the cover on. Most areas of the heatsink are slightly cooler than
that (in the high 80s or lower-middle 90s).

Later, when I get some free time, I plan to install two small fans on the
heatsink, helping to pull air over it and hopefully keep that hybrid alive
and comfortable.

It has been suggested that minorly violent and mostly non-destructive
disassembly of an STK-series hybrid amplifier is possible. Some people even
make the claim of having repaired the bad parts within. I may just have to
try it if the old hybrid hasn't walked off yet.

The DC offset as measured at the speaker terminals (no source playing, no
speakers attached of course) is between 8-12mV for both channels now. I
believe the unit to be fixed. :-)

William

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