sci.electronics.repair@googlegroups.com

Today's topics:

* Power transistor question... - 4 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/48e3a91c572ef00c?hl=en
* Wall Warts - 8 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/de407a5056a54ee0?hl=en
* Valves badged Orange , rebadged what make? - 5 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/b405f7894dddeac4?hl=en
* how to disassemble this AC Adapter? - 7 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/79c2e64c02b38c5d?hl=en
* microwave oven stopping prematurely, repairable? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/a4366967d76451a5?hl=en

==============================================================================
TOPIC: Power transistor question...
http://groups.google.com/group/sci.electronics.repair/t/48e3a91c572ef00c?hl=en
==============================================================================

== 1 of 4 ==
Date: Sat, May 28 2011 11:19 pm
From: "Phil Allison"

"Ken"
"Phil Allison"
> "Dave"
>> "Phil Allison"
>> >
>> >> The first thing to check is all the filter and coupling electros in
>> >> the
>> >> vertical and PSU for the vertical.
>> >>
>> >> You need an ESR meter or lotsa luck.
>> >>
>> > Guess I'll need lotsa luck. What does an ESR meter actually measure,
>> > pray tell?
>>
>> ** It will tell you if an electro cap has or is about to die of old age.
>>
>> Does this by measuring its internal resistance or ESR independent of
>> actual
>> cap value in microfarads.
>>
>> ESR = Equivalent Series Resistance.
>>
>> http://en.wikipedia.org/wiki/Equivalent_series_resistance#Capacitors
>>
>
> A good one
> http://www.peakelec.co.uk/acatalog/jz_esr70.html

** Looks very nice.

Such ESR meters can also measure the ESR of cells, both rechargeable and
non-rechargeable types -the very low test current means they can check
Lithium button cells too.

The ESR of non-rechageables is good guide to remaining capacity - far
better than voltage is.

The ESR of a NiCd or NiMH cell is a good guide to its heath and ability to
deliver high currents.

Egs:

AA alkaline = 0.1 ohms new, rising to about 2 ohms at end of life.

AA carbon/zinc = 0.5 ohms new, rising to 5 ohms at end of life.

AA NiCd or NiMH = 0.03 ohms new, rising to 0.5 ohms at end of useful
life.

9V volt alkaline = 0.8 ohms new, rising to 10 ohms at end of life.

Lithium button cell ( ie CR2032 ) = 10 to 15 ohms new, rising to 50 ohms
at end of life.

.... Phil

== 2 of 4 ==
Date: Sun, May 29 2011 4:26 am
From: "Dave"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:94e6r1Frd6U1@mid.individual.net...
>
> "Ken"
> "Phil Allison"
>> "Dave"
>>> "Phil Allison"
>>> >
>>> >> The first thing to check is all the filter and coupling electros in
>>> >> the
>>> >> vertical and PSU for the vertical.
>>> >>
>>> >> You need an ESR meter or lotsa luck.
>>> >>
>>> > Guess I'll need lotsa luck. What does an ESR meter actually
>>> > measure,
>>> > pray tell?
>>>
>>> ** It will tell you if an electro cap has or is about to die of old
>>> age.
>>>
>>> Does this by measuring its internal resistance or ESR independent of
>>> actual
>>> cap value in microfarads.
>>>
>>> ESR = Equivalent Series Resistance.
>>>
>>> http://en.wikipedia.org/wiki/Equivalent_series_resistance#Capacitors
>>>
> >
>> A good one
>> http://www.peakelec.co.uk/acatalog/jz_esr70.html
>
>
> ** Looks very nice.
>
> Such ESR meters can also measure the ESR of cells, both rechargeable and
> non-rechargeable types -the very low test current means they can check
> Lithium button cells too.
>
> The ESR of non-rechageables is good guide to remaining capacity - far
> better than voltage is.
>
> The ESR of a NiCd or NiMH cell is a good guide to its heath and ability to
> deliver high currents.
>
> Egs:
>
> AA alkaline = 0.1 ohms new, rising to about 2 ohms at end of life.
>
> AA carbon/zinc = 0.5 ohms new, rising to 5 ohms at end of life.
>
> AA NiCd or NiMH = 0.03 ohms new, rising to 0.5 ohms at end of useful
> life.
>
> 9V volt alkaline = 0.8 ohms new, rising to 10 ohms at end of life.
>
> Lithium button cell ( ie CR2032 ) = 10 to 15 ohms new, rising to 50 ohms
> at end of life.
>
>
> .... Phil
>

Thank you Ken, and Phil. I had no idea. Definitely want one of those.
Much appreciated.

So anyway, if my voltages look good and there's no serious ripple anywhere,
I'm thinking more and more about the electro caps, but really don't fancy
pulling each and every one out to test without having some sort of strategy
as to which to test first. Any ideas on that? Larger ones first? What
would you guys do? I truly do appreciate the help and ideas.

Dave

== 3 of 4 ==
Date: Sun, May 29 2011 5:49 am
From: "Phil Allison"

"Dave"
>
> Thank you Ken, and Phil. I had no idea. Definitely want one of those.
> Much appreciated.
>
> So anyway, if my voltages look good and there's no serious ripple
> anywhere, I'm thinking more and more about the electro caps, but really
> don't fancy pulling each and every one out to test without having some
> sort of strategy as to which to test first. Any ideas on that? Larger
> ones first? What would you guys do? I truly do appreciate the help and
> ideas.
>

** OK - the " old school " way of doing this tedious task was to briefly
parallel any suspect electo with a similar value and voltage cap while the
set is operating.

And see WTF happens.

TV service was never a game for the faint hearted..............

.... Phil

== 4 of 4 ==
Date: Sun, May 29 2011 8:13 am
From: "Dave"

"Dave" <db5151@hotmail.com> wrote in message
news:N72dnaJJw6PhsH_QnZ2dnUVZ_hKdnZ2d@posted.internetamerica...
>
> "Phil Allison" <phil_a@tpg.com.au> wrote in message
> news:94e6r1Frd6U1@mid.individual.net...
>>
>> "Ken"
>> "Phil Allison"
>>> "Dave"
>>>> "Phil Allison"
>>>> >
>>>> >> The first thing to check is all the filter and coupling electros in
>>>> >> the
>>>> >> vertical and PSU for the vertical.
>>>> >>
>>>> >> You need an ESR meter or lotsa luck.
>>>> >>
>>>> > Guess I'll need lotsa luck. What does an ESR meter actually
>>>> > measure,
>>>> > pray tell?
>>>>
>>>> ** It will tell you if an electro cap has or is about to die of old
>>>> age.
>>>>
>>>> Does this by measuring its internal resistance or ESR independent of
>>>> actual
>>>> cap value in microfarads.
>>>>
>>>> ESR = Equivalent Series Resistance.
>>>>
>>>> http://en.wikipedia.org/wiki/Equivalent_series_resistance#Capacitors
>>>>
>> >
>>> A good one
>>> http://www.peakelec.co.uk/acatalog/jz_esr70.html
>>
>>
>> ** Looks very nice.
>>
>> Such ESR meters can also measure the ESR of cells, both rechargeable and
>> non-rechargeable types -the very low test current means they can check
>> Lithium button cells too.
>>
>> The ESR of non-rechageables is good guide to remaining capacity - far
>> better than voltage is.
>>
>> The ESR of a NiCd or NiMH cell is a good guide to its heath and ability
>> to deliver high currents.
>>
>> Egs:
>>
>> AA alkaline = 0.1 ohms new, rising to about 2 ohms at end of life.
>>
>> AA carbon/zinc = 0.5 ohms new, rising to 5 ohms at end of life.
>>
>> AA NiCd or NiMH = 0.03 ohms new, rising to 0.5 ohms at end of useful
>> life.
>>
>> 9V volt alkaline = 0.8 ohms new, rising to 10 ohms at end of life.
>>
>> Lithium button cell ( ie CR2032 ) = 10 to 15 ohms new, rising to 50
>> ohms at end of life.
>>
>>
>> .... Phil
>>
>
> Thank you Ken, and Phil. I had no idea. Definitely want one of those.
> Much appreciated.
>
> So anyway, if my voltages look good and there's no serious ripple
> anywhere, I'm thinking more and more about the electro caps, but really
> don't fancy pulling each and every one out to test without having some
> sort of strategy as to which to test first. Any ideas on that? Larger
> ones first? What would you guys do? I truly do appreciate the help and
> ideas.
>
> Dave
>
>

Now believe I already have an ESR meter, though I didn't realize that was
one of its functions. What I have is an Extech 380193 LCR meter, which
tells me that a fairly new but run of the mill 1uF electrolytic cap out of
my junkbox has 12.5 Ohms of resistance. If I were to try to use this to
measure the caps in-circuit, how should I proceed? I am guessing that
discharging the cap before touching my test leads to the solder pads would
give me a reading, but I really hesitate to do this without some sort of
suggestion that such is a safe proceedure for my meter. Am guessing that
readings in the single digits indicate a defective device. Does this sound
reasonable? No power to the circuit under test, of course, and likely will
push in the power button a few minutes before beginning. Again, any advice
is appreciated.

Thanks,

Dave

==============================================================================
TOPIC: Wall Warts
http://groups.google.com/group/sci.electronics.repair/t/de407a5056a54ee0?hl=en
==============================================================================

== 1 of 8 ==
Date: Sun, May 29 2011 7:29 am
From: Jeff Liebermann

On Fri, 27 May 2011 22:10:49 -0500, Puddin' Man
<puddingDOTman@gmail.com> wrote:

>>First,
>>just measure the terminal voltage of the battery pack after it's been
>>sitting around for a day without being charged. Even if totally
>>discharged, it should have at least 1.1 volts per cell or about 7.7VDC
>>across the terminals. A fully charged NiCd will have about 1.45VDC
>>per cell or about 10.2VDC across the terminals.
>
>I measure just under 4vdc for the pack. Your opinion is
>solicited.

Your battery pack is dead, kaput, eWaste, gone, shorted, etc. That's
what probably killed the wall wart and inspired the recall. Charging
a shorted cell is a great way to overheat an unprotected transformer.
If you simply replace the transformer, you're likely to fry it again.

>>Now, if you really want to test you battery packs, I have a West Mtn
>>Radio CBA-IIv1:
>><http://www.westmountainradio.com/product_info.php?products_id=cba3>
>
>Only $150-300. Lordy mercy!

The requisite computer is not included in the price. I use it to
characterize Li-Ion mutations for model airplanes, robotics, cell
phones, and general havoc. The energy available is basically the area
under the discharge curve.

>ATLINKS USA
>Telephone power supply
>Input: AC120V 60hz 4.4w
>Output: DC 9v 200 mA
>Class 2 transformer
>UL etc
>
>but when I measure, I get about 20vdc from my meter.
>Any idea why the drastic difference from spec?

Sure. You're measuring the voltage without a load. If you load the
xformer with a 200ma load:
R = 9V / 0.2A = 45 ohms (47 ohms is close enough)
and
Power = E*I = 9v * 0.2A = 1.8 Watts (so use 5 watt resistor)
you should get around 9V DC.

--
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 8 ==
Date: Sun, May 29 2011 7:46 am
From: Jeff Liebermann

On Sat, 28 May 2011 15:38:14 -0500, Jim Yanik <jyanik@abuse.gov>
wrote:

>Jeff Liebermann <jeffl@cruzio.com> wrote in
>news:2ag0u6hqsttr5ri4j5ogvgkosj7ihhlseu@4ax.com:
>> Sorry. C is the current rating of the battery in ampere-hours. A
>> typical NiCd pack, full of AA cells will have a rating of about 750
>> ma-hr. NiMH would be around 1200 to 2200 ma-hr.

>Just a FYI,I have some Everready NiMH AA cells rated at 2350 mAH(bought at
>Wal-Mart),and saw some no-name 2800 mAH AA cells for sale on Ebay.

Amazing. I've run tests on some 2200 ma-hr NiMH AA cells using my
CBA-II
<http://www.westmountainradio.com/product_info.php?products_id=cba3>
The results are not very impressive. If I discharge at rediculously
low rates, such as 0.01C, I might be able to squeeze 2200 ma-hr out of
a cell. I tested one at about twice the estimated self discharge
rate, and calculated about 5000 ma-hr out of the cell. I think it
took about a week to finish the test. However, when I ran it at a
more realistic load of 2C, I was barely able to squeeze out 1000
ma-hr. This was also for a brand new cell, as repeated
charge/discharge cycles would also decrease the cell capacity.

See the discharge curves at:
<http://4gdo.com/batfaq.htm#Question%20#4:>
Note how the area under the curve decreases with increasing load.

I keep planning to post some test results, but never seem to have the
time to organize anything. Sorry(tm).

--
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

== 3 of 8 ==
Date: Sun, May 29 2011 7:59 am
From: "Geoffrey S. Mendelson"

Jeff Liebermann wrote:
> This was also for a brand new cell, as repeated
> charge/discharge cycles would also decrease the cell capacity.

Funny, I've always read the opposite with Nimh cells, they need to go through
several charge/discharge cycles before they reach full capacity.

This is especially true of the long discharge ones, which come "pre-charged"
at about 80% and then at least in my experience take 5-10 cycles to come
up to a useable capacity. It also seems in my experience that the lower the
charge rate, the more cycles a cell needs.

BTW, if you have any info on charging an Azden HT, please let me know.

Thanks,

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Making your enemy reliant on software you support is the best revenge.

== 4 of 8 ==
Date: Sun, May 29 2011 8:22 am
From: "William Sommerwerck"

"Geoffrey S. Mendelson" <gsm@mendelson.com> wrote in message
news:slrniu4nnd.fpd.gsm@cable.mendelson.com...
> Jeff Liebermann wrote:

>> This was also for a brand new cell, as repeated
>> charge/discharge cycles would also decrease the cell capacity.

> Funny, I've always read the opposite with NiMH cells. They need
> to go through several charge/discharge cycles before they reach
> full capacity.

This has always been the "conventional wisdom" about nicads, as well.

I wish I knew what the "truth" about rechargeables was. Contrary to the
common belief, I've never had problems with rapid self-discharge with NiMHs.

== 5 of 8 ==
Date: Sun, May 29 2011 8:24 am
From: Jeff Liebermann

On Sun, 29 May 2011 14:59:03 +0000 (UTC), "Geoffrey S. Mendelson"
<gsm@mendelson.com> wrote:

>Jeff Liebermann wrote:
>> This was also for a brand new cell, as repeated
>> charge/discharge cycles would also decrease the cell capacity.
>
>Funny, I've always read the opposite with Nimh cells, they need to go through
>several charge/discharge cycles before they reach full capacity.

I've never seen that. Nothing similar found with Google or on my
favorite sites:
<http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery>
<http://batteryuniversity.com>
<http://batteryuniversity.com/learn/article/Nickel_based_batteries>

Where I have seen something like this is with cheap Chinese laptop
battery packs. The problem is not the battery. It's the charge
controller inside the battery. It has to be run up and down in
voltage and "trained" before it knows how the pack is going to act.
This is usually done at the factory by reputable battery pack
manufacturers, but seems to be avoided by others. I've personally
only seen this with Li-Ion battery packs, but am told that it's also a
problem with older chemistries.

>This is especially true of the long discharge ones, which come "pre-charged"
>at about 80% and then at least in my experience take 5-10 cycles to come
>up to a useable capacity. It also seems in my experience that the lower the
>charge rate, the more cycles a cell needs.

That's probably because NiMH has a rather high self-discharge rate.
They may have been at 100% when they left the factory, but have
self-discharged in the box. Also, the ideal storage charge level is
about 40% for NiMH. None of the NiMH batteries I've tested (Duracell,
Rayovac, Sanyo, Energizer, various no-name, and various OEM) have
showed anything other than a slow loss of capacity (area under the
curve) for repeated charge/discharge cycles.

>BTW, if you have any info on charging an Azden HT, please let me know.

No experience. This might help if it uses NiMH:
<http://batteryuniversity.com/learn/article/charging_nickel_metal_hydride>

Note that most of my experiments have been on single cells, not
battery packs.

--
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 8 ==
Date: Sun, May 29 2011 8:29 am
From: Jeff Liebermann

On Sat, 28 May 2011 15:38:14 -0500, Jim Yanik <jyanik@abuse.gov>
wrote:

>Just a FYI,I have some Everready NiMH AA cells rated at 2350 mAH(bought at
>Wal-Mart),and saw some no-name 2800 mAH AA cells for sale on Ebay.

Argh. I haven't been paying attention.
Duracell 2650 2650 ma-hr
Energizer e2 2500 ma-hr
Maha Powerex AA 2700 ma-hr
Maybe I'll do some shopping and testing (timer permitting).

--
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

== 7 of 8 ==
Date: Sun, May 29 2011 8:39 am
From: Jeff Liebermann

On Sun, 29 May 2011 07:46:08 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>Amazing. I've run tests on some 2200 ma-hr NiMH AA cells using my
>CBA-II
><http://www.westmountainradio.com/product_info.php?products_id=cba3>

Here's some result from the RC groups on NiMH packs.
<http://www.rcgroups.com/forums/attachment.php?attachmentid=642246>
At 0.5A discharge rate, various manufacturers yielded 1700 to 2000
ma-hr.

At 0.25A, this Sanyo battery pack managed to squeeze out 1275 ma-hr:
<http://www.rcgroups.com/forums/attachment.php?attachmentid=2330249>

More of the same for 1900 ma-hr:
<http://www.rcgroups.com/forums/attachment.php?attachmentid=2328003>

This is somewhat better than what I was getting.

--
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

== 8 of 8 ==
Date: Sun, May 29 2011 10:08 am
From: Puddin' Man

Many thanks.

S'long,
P

On Sun, 29 May 2011 07:29:38 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:

>On Fri, 27 May 2011 22:10:49 -0500, Puddin' Man
><puddingDOTman@gmail.com> wrote:
>
>>>First,
>>>just measure the terminal voltage of the battery pack after it's been
>>>sitting around for a day without being charged. Even if totally
>>>discharged, it should have at least 1.1 volts per cell or about 7.7VDC
>>>across the terminals. A fully charged NiCd will have about 1.45VDC
>>>per cell or about 10.2VDC across the terminals.
>>
>>I measure just under 4vdc for the pack. Your opinion is
>>solicited.
>
>Your battery pack is dead, kaput, eWaste, gone, shorted, etc. That's
>what probably killed the wall wart and inspired the recall. Charging
>a shorted cell is a great way to overheat an unprotected transformer.
>If you simply replace the transformer, you're likely to fry it again.
>
>>>Now, if you really want to test you battery packs, I have a West Mtn
>>>Radio CBA-IIv1:
>>><http://www.westmountainradio.com/product_info.php?products_id=cba3>
>>
>>Only $150-300. Lordy mercy!
>
>The requisite computer is not included in the price. I use it to
>characterize Li-Ion mutations for model airplanes, robotics, cell
>phones, and general havoc. The energy available is basically the area
>under the discharge curve.
>
>>ATLINKS USA
>>Telephone power supply
>>Input: AC120V 60hz 4.4w
>>Output: DC 9v 200 mA
>>Class 2 transformer
>>UL etc
>>
>>but when I measure, I get about 20vdc from my meter.
>>Any idea why the drastic difference from spec?
>
>Sure. You're measuring the voltage without a load. If you load the
>xformer with a 200ma load:
> R = 9V / 0.2A = 45 ohms (47 ohms is close enough)
>and
> Power = E*I = 9v * 0.2A = 1.8 Watts (so use 5 watt resistor)
>you should get around 9V DC.

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

==============================================================================
TOPIC: Valves badged Orange , rebadged what make?
http://groups.google.com/group/sci.electronics.repair/t/b405f7894dddeac4?hl=en
==============================================================================

== 1 of 5 ==
Date: Sun, May 29 2011 8:11 am
From: "N_Cook"

While at it with Orange amps. Nasty metallic buzz like mains powered shaver/
engraver/ poodle clippers. Varying level of noise with amount of load.
Mains Tx central bar of an outer "E" lamination loose. Simple enough to deal
with once you know the cause. Remove the matching "I" to drible lacquer both
sides. The wiring bobbin is loose within the iron laminations block, so
plenty of space to allow a lamination to break away. Will also push some
silicone rubber sheet in there to avoid re-occurance hopefully.

== 2 of 5 ==
Date: Sun, May 29 2011 8:15 am
From: spamtrap1888

On May 29, 8:11 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> While at it with Orange amps. Nasty metallic buzz like mains powered shaver/
> engraver/ poodle clippers. Varying level of noise with amount of  load.
> Mains Tx central bar of an outer "E" lamination loose. Simple enough to deal
> with once you know the cause. Remove the matching "I" to drible lacquer both
> sides. The wiring bobbin is loose within the iron laminations block, so
> plenty of space to allow a lamination to break away. Will also push some
> silicone rubber sheet in there to avoid re-occurance hopefully.

They sound like absolute garbage. Were Orange amps ever any good?

== 3 of 5 ==
Date: Sun, May 29 2011 8:29 am
From: "N_Cook"

spamtrap1888 <spamtrap1888@gmail.com> wrote in message
news:3ceaba6a-6e5b-4e3a-880f-ae17ec71abf3@y27g2000prb.googlegroups.com...
On May 29, 8:11 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> While at it with Orange amps. Nasty metallic buzz like mains powered
shaver/
> engraver/ poodle clippers. Varying level of noise with amount of load.
> Mains Tx central bar of an outer "E" lamination loose. Simple enough to
deal
> with once you know the cause. Remove the matching "I" to drible lacquer
both
> sides. The wiring bobbin is loose within the iron laminations block, so
> plenty of space to allow a lamination to break away. Will also push some
> silicone rubber sheet in there to avoid re-occurance hopefully.

They sound like absolute garbage. Were Orange amps ever any good?

+++++

They must be esceedingly good because they are exceedingly expensive.
Makes you wonder what the difference is , in Sterling terms, the money going
out to China for making the things compared to the UK selling price.

== 4 of 5 ==
Date: Sun, May 29 2011 10:26 am
From: "N_Cook"

spamtrap1888 <spamtrap1888@gmail.com> wrote in message
news:3ceaba6a-6e5b-4e3a-880f-ae17ec71abf3@y27g2000prb.googlegroups.com...
On May 29, 8:11 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> While at it with Orange amps. Nasty metallic buzz like mains powered
shaver/
> engraver/ poodle clippers. Varying level of noise with amount of load.
> Mains Tx central bar of an outer "E" lamination loose. Simple enough to
deal
> with once you know the cause. Remove the matching "I" to drible lacquer
both
> sides. The wiring bobbin is loose within the iron laminations block, so
> plenty of space to allow a lamination to break away. Will also push some
> silicone rubber sheet in there to avoid re-occurance hopefully.

They sound like absolute garbage. Were Orange amps ever any good?

++++

The other notorious Orange problem - intermittant loss of one channel,
whether by sw on front or footswitch.
Although they use latching 1/4 inch spade connectors, just because they will
not dislodge, does not necessarily mean they retain electrical connection.

== 5 of 5 ==
Date: Sun, May 29 2011 3:21 pm
From: "Gareth Magennis"

"Meat Plow" <mhywattt@yahoo.com> wrote in message
news:pan.2011.05.28.22.58.44@emutt.macspoofer.lmao...
> On Sat, 28 May 2011 14:33:30 +0100, Gareth Magennis wrote:
>
>> "Gareth Magennis" <sound.service@btconnect.com> wrote in message
>> news:mLWDp.24219$Am5.16040@newsfe05.ams2...
>>>
>>> . Best for my concern would be some NOS Mullards
>>>> or RCA.
>>>
>>>
>>>
>>> Yeah well, we could all say that.
>>> Doesn't help.
>>
>>
>> Sorry, that post reads a little curt, but for example:
>>
>> http://cgi.ebay.co.uk/EL34-CV1741-MULLARD-NOS-MATCHED-
> PAIR-/310210519111?
> pt=UK_Consumer_VintageAudio_RL&hash=item4839fce047Blimey.Gareth.
>
> I know a few that wouldn't bat an eyelash at that price.

You could experiment to see if any of them could really tell the difference
in a properly controlled double blind test.

I am highly suspicious of any opinions regarding "sound quality" obtained
otherwise.

Gareth.

==============================================================================
TOPIC: how to disassemble this AC Adapter?
http://groups.google.com/group/sci.electronics.repair/t/79c2e64c02b38c5d?hl=en
==============================================================================

== 1 of 7 ==
Date: Sun, May 29 2011 10:47 am
From: Robert Macy

Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
IB-PS365, 55W 16V 3.4A

The thing has gone intermittent. By slightly flexing the case, comes
back on, so idea is to disassemble, solder traces and be up and
running instantly.

but...how to disassemble?

Anybody done that?

== 2 of 7 ==
Date: Sun, May 29 2011 11:35 am
From: "Shaun"

"Robert Macy" wrote in message
news:0846d61c-401a-4f59-a997-cbe45a3c8cf4@w21g2000yqm.googlegroups.com...

Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
IB-PS365, 55W 16V 3.4A

The thing has gone intermittent. By slightly flexing the case, comes
back on, so idea is to disassemble, solder traces and be up and
running instantly.

but...how to disassemble?

Anybody done that?

You could try dropping on a hard floor, or using a hammer, pound on the
corners abit all around wallwart where the seam is.
I know this sounds crude, but often it works. Another way is to use a
dremel mototool with a cutoff disk and cut along the seam all around the
wallwart.

good luck,

Shaun

== 3 of 7 ==
Date: Sun, May 29 2011 11:57 am
From: Jeff Liebermann

On Sun, 29 May 2011 10:47:00 -0700 (PDT), Robert Macy
<macy@california.com> wrote:

>Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
>IB-PS365, 55W 16V 3.4A
>
>The thing has gone intermittent. By slightly flexing the case, comes
>back on, so idea is to disassemble, solder traces and be up and
>running instantly.
>
>but...how to disassemble?
>
>Anybody done that?

Sure. I do it all the time. However, I've rarely found an
intermittent inside. It's usually a broken cord or plug. Be sure
it's not the cord before proceeding. I use 3 methods (in order of
increasing brutality).

1. Stuff the charger in a bench vice with some wood blocks for
padding. The glue line should be facing the jaws. Apply pressure
until you hear a cracking sound. Hopefully, it's the glue line, not
something inside. If see a gap, use a pry bar (I use a bicycle tire
tool) to open.

Others have suggested putting it in the fridge overnight, which will
make the plastic and glue more brittle. Seems reasonable, although
I've never tried it.

2. Find a masons chisel.
<http://www.google.com/search?q=masons+chisel&hl=en&prmd=ivns&tbm=isch>
Place the business end along the glue line and start pounding. The
idea is to crack the glue, not the case.

3. If the above fail, it's time to saw it open. I use a hack saw and
bench vise. Saw along the glue line half way through the plastic.
Again, the idea is to crack the glue line, not cut all the way
through. Reassembly will require some glue, and cosmetic (black
electrical) tape to hide the damage. If I can get half way through,
the case will usually come apart. This also works well for battery
packs.

If all else fails, you can get replacements on eBay for about $10-$15.
<http://shop.ebay.com/i.html?_kw=55W&_kw=16V>

More:
<http://www.ehow.com/how_5013187_open-laptop-power-supply.html>

--
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

== 4 of 7 ==
Date: Sun, May 29 2011 12:21 pm
From: "N_Cook"

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:vo45u61l2kcl2gulqcijqhpq0i14ckqf3t@4ax.com...
> On Sun, 29 May 2011 10:47:00 -0700 (PDT), Robert Macy
> <macy@california.com> wrote:
>
> >Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
> >IB-PS365, 55W 16V 3.4A
> >
> >The thing has gone intermittent. By slightly flexing the case, comes
> >back on, so idea is to disassemble, solder traces and be up and
> >running instantly.
> >
> >but...how to disassemble?
> >
> >Anybody done that?
>
> Sure. I do it all the time. However, I've rarely found an
> intermittent inside. It's usually a broken cord or plug. Be sure
> it's not the cord before proceeding. I use 3 methods (in order of
> increasing brutality).
>
> 1. Stuff the charger in a bench vice with some wood blocks for
> padding. The glue line should be facing the jaws. Apply pressure
> until you hear a cracking sound. Hopefully, it's the glue line, not
> something inside. If see a gap, use a pry bar (I use a bicycle tire
> tool) to open.
>
> Others have suggested putting it in the fridge overnight, which will
> make the plastic and glue more brittle. Seems reasonable, although
> I've never tried it.
>
> 2. Find a masons chisel.
> <http://www.google.com/search?q=masons+chisel&hl=en&prmd=ivns&tbm=isch>
> Place the business end along the glue line and start pounding. The
> idea is to crack the glue, not the case.
>
> 3. If the above fail, it's time to saw it open. I use a hack saw and
> bench vise. Saw along the glue line half way through the plastic.
> Again, the idea is to crack the glue line, not cut all the way
> through. Reassembly will require some glue, and cosmetic (black
> electrical) tape to hide the damage. If I can get half way through,
> the case will usually come apart. This also works well for battery
> packs.
>
> If all else fails, you can get replacements on eBay for about $10-$15.
> <http://shop.ebay.com/i.html?_kw=55W&_kw=16V>
>
> More:
> <http://www.ehow.com/how_5013187_open-laptop-power-supply.html>
>
>
> --
> 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

First is to remove any sticky labels that may cover a securing screw.
Refining point 1 , place in vice with the weakest point in the line , where
one of the cables exits.
A guitar plectrum is best to start with as a pry-bar as minimum damage,
progress to screwdrivers etc later.

== 5 of 7 ==
Date: Sun, May 29 2011 1:30 pm
From: Robert Macy

I didn't immediately start prying, because one end, where the AC cord
connector is, seems to flex back and forth, not at all like it is
glued rigidyl in place. However, the other end, where the power cord
continues to the laptop, is very rigid, like glue,...or a screw.

By pressing around the metal stick on label, a small detent at that
end appeared. Thinking it was a mounting screw, I removed only the
small round bit covering the screw and that revealed what looks more
liike a small pot screw head - for adjusting voltage?

From Jeff Lieberman's excellent URL, I started prying and VOILA! The
case is indeed plastic detent, not glued!

It literally pops apart. The tool in this case was the very thick
HYDE joint knife, the one that is not flexible [too thick] and tapers
to a knife edge. But be careful more than once I've slipped with this
awkward tool and it is a knife edge, always plan for a slip and
envision the path the knife will travel, ...else it takes several
weeks to recover.

Now inside the PCB is covered with a copper foil for EMC, so can't get
ready access to the traces. And, yes, the screw is a pot
adjustment.

But, hey the case is NOW open

I don't see anything immediately. but glued down fish paper and
copper shield block a lot. The unit used to fail with the LED simply
going OFF. If ON, unit was ok. Could be a lot between the AC mains
and that LED, though.

On May 29, 12:21 pm, "N_Cook" <dive...@tcp.co.uk> wrote:
> Jeff Liebermann <je...@cruzio.com> wrote in message
>
> news:vo45u61l2kcl2gulqcijqhpq0i14ckqf3t@4ax.com...
>
>
>
>
>
> > On Sun, 29 May 2011 10:47:00 -0700 (PDT), Robert Macy
> > <m...@california.com> wrote:
>
> > >Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
> > >IB-PS365, 55W 16V 3.4A
>
> > >The thing has gone intermittent.  By slightly flexing the case, comes
> > >back on, so idea is to disassemble, solder traces and be up and
> > >running instantly.
>
> > >but...how to disassemble?
>
> > >Anybody done that?
>
> > Sure.  I do it all the time.  However, I've rarely found an
> > intermittent inside.  It's usually a broken cord or plug.  Be sure
> > it's not the cord before proceeding.  I use 3 methods (in order of
> > increasing brutality).
>
> > 1.  Stuff the charger in a bench vice with some wood blocks for
> > padding.  The glue line should be facing the jaws.  Apply pressure
> > until you hear a cracking sound.  Hopefully, it's the glue line, not
> > something inside.  If see a gap, use a pry bar (I use a bicycle tire
> > tool) to open.
>
> > Others have suggested putting it in the fridge overnight, which will
> > make the plastic and glue more brittle.  Seems reasonable, although
> > I've never tried it.
>
> > 2.  Find a masons chisel.
> > <http://www.google.com/search?q=masons+chisel&hl=en&prmd=ivns&tbm=isch>
> > Place the business end along the glue line and start pounding.  The
> > idea is to crack the glue, not the case.
>
> > 3.  If the above fail, it's time to saw it open.  I use a hack saw and
> > bench vise.  Saw along the glue line half way through the plastic.
> > Again, the idea is to crack the glue line, not cut all the way
> > through.  Reassembly will require some glue, and cosmetic (black
> > electrical) tape to hide the damage.  If I can get half way through,
> > the case will usually come apart.  This also works well for battery
> > packs.
>
> > If all else fails, you can get replacements on eBay for about $10-$15.
> > <http://shop.ebay.com/i.html?_kw=55W&_kw=16V>
>
> > More:
> > <http://www.ehow.com/how_5013187_open-laptop-power-supply.html>
>
> > --
> > 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
>
> First is to remove any sticky labels that may cover a securing screw.
> Refining point 1 , place in vice with the weakest point in the line , where
> one of the cables exits.
> A guitar plectrum is best to start with as a pry-bar as minimum damage,
> progress to screwdrivers etc later.

== 6 of 7 ==
Date: Sun, May 29 2011 3:02 pm
From: "William Sommerwerck"

As someone else suggested, an intermittent power supply is almost always
caused by a defective cable. Regardless, now that it's open, you can touch
up all the solder joints, and put an ohmeter on the power cord.

== 7 of 7 ==
Date: Sun, May 29 2011 3:20 pm
From: Robert Macy

On May 29, 3:02 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:
> As someone else suggested, an intermittent power supply is almost always
> caused by a defective cable. Regardless, now that it's open, you can touch
> up all the solder joints, and put an ohmeter on the power cord.

I was actually suspecting the PCB connector for the AC mains cable.
All that flexing into the right angle mount with NO strain relief has
got to take its toll. Seemed likely there would be cracks around the
mounting/electrical pins.

I hate tearing into the fish paper/copper foil wrap. Some of the best
workmanship in shielding I've seen although it's incredible the shield
is connected via a 3/4 inch long 22 Awg solid wire to a point on the
PCB where the PC cable connector is mounted. However, sometimes NOT
doing something right can suffice, especially on small packages.

==============================================================================
TOPIC: microwave oven stopping prematurely, repairable?
http://groups.google.com/group/sci.electronics.repair/t/a4366967d76451a5?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 29 2011 1:39 pm
From: tin6150

On May 28, 10:32 pm, mike <spam...@gmail.com> wrote:
> tin6150 wrote:
> > Hello folks, happy Memorial Day weekend to you all!
>
> > My microwave is acting erratic, maybe you can help me see if it is
> > repairable?  It can heat water, but tends to shut downs prematurely.
>
> > I have read this repair faq
> >http://www.repairfaq.org/sam/micfaq.htm#micsaf
> > but didn't find answer to my problem.
>
> > One evening I was cooking a frozen dinner, a chicken pot pie with a
> > mesh for browning at the top of the paper container.  It is said to be
> > microwave safe.  I followed instructions exactly.  But maybe 3 minutes
> > into the nuking, there were a few spark, so I pulled the power cord as
> > quickly as I could.  There were some burn smell, which lingered even
> > after a week of non-use.  The microwave oven was clean, no spill over
> > or splatter when I started nuking the pot pie.  I did not leave a fork
> > in there either.
>
> > The microwave in question is a panasonic inverter system, 1200 W.
> > manufacture date is 2002.
>
> > Currently, all electronics seems to work fine, touch pad works, clock
> > runs, timer works.  no visible damage.  No paint problem from the
> > spark.  I tried to heat a cup of water for 35 seconds, and microwave
> > just shut off automatically after some 15-20 seconds (but clock panel
> > still running, so the electronics seems to have shut something down.
> > No error indicator of any sort that I can see).
>
> > If I set power to 50%, then it will heat the water for 50 seconds to
> > completion.  water temperature is very warm to the touch.  If I set
> > power to 10%, then it will heat for more than 70 seconds to
> > completion.
>
> > Maybe eventually at more than 50 seconds even at the 50% power, it
> > might shut off automatically when something gets too hot?  I am not
> > sure if I want to try it if microwave isn't really going to be fully
> > functional anyway.
>
> > It is likely cheaper to just buy a new one, but as an
> > environmentalist, I just hate to waste appliance that can otherwise
> > work :)
>
> > Much thanks in advance for any advices.
> > Tin
>
> is the cooling fan running?

Thanks Mike.
And yes, cooling fan next to the power supply runs. I hear humming
noise of the microwave coming on, so my guess every moving part is
working...

-Tin

== 2 of 2 ==
Date: Sun, May 29 2011 2:59 pm
From: "William Sommerwerck"

It appears that "something" is overheating that causes the klystron to lose
power, and this "something" gets warmer with higher power settings. If that
"something" is not a component /intended/ to shut off the unit when it
overheats, you'll probably have a hard time finding it.

Freeze-spray might locate it. Otherwise, I vote for buying a new unit.

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