sci.electronics.repair@googlegroups.com

Today's topics:

* Fake Audio Amp IC? - 8 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/26c6b4ae574ca1f2?hl=en
* Recommendation for electronics forums? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/a2a97ca7806d8277?hl=en
* Oral-b Braun electronic toothbrush problem - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/49caca46fe47e846?hl=en
* Running a PC outside of a computer case - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/767389e3dda5bc79?hl=en
* HDTV has no sound - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/3a7aee93765769fb?hl=en
* SECRET SEEMS - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/10d332afe33dced0?hl=en

==============================================================================
TOPIC: Fake Audio Amp IC?
http://groups.google.com/group/sci.electronics.repair/t/26c6b4ae574ca1f2?hl=en
==============================================================================

== 1 of 8 ==
Date: Mon, Mar 21 2011 2:08 pm
From: "Gareth Magennis"

Hi,

I recently replaced the STK amplifier module in a Genelec speaker. These
STK modules are not easy to find, but I did find one on the net, delivered
from the far east, which was a quarter of the price of the official spares
supplier here in the UK (HHB). I informed the customer prior to order, and
he was happy to take the much cheaper part.

Anyway it lasted 1 day before failing short circuit. Fortunately the
drivers are not damaged.

There are photos here:
http://postimage.org/image/1gb2ui0lg/
http://postimage.org/image/2p2rdrs9w/

The new looking part is a new part subsequently ordered from HHB. The old
one with the mangled legs is the cheap failed device.

Is anyone able to tell whether this might or might not be fake?

Cheers,

Gareth.

== 2 of 8 ==
Date: Mon, Mar 21 2011 2:35 pm
From: "Colin Horsley"

"Gareth Magennis" <sound.service@btconnect.com> wrote in message
news:j7Php.143670$XM7.118285@newsfe18.ams2...
: Hi,
:
: I recently replaced the STK amplifier module in a Genelec speaker. These
: STK modules are not easy to find, but I did find one on the net, delivered
: from the far east, which was a quarter of the price of the official spares
: supplier here in the UK (HHB). I informed the customer prior to order, and
: he was happy to take the much cheaper part.
:
: Anyway it lasted 1 day before failing short circuit. Fortunately the
: drivers are not damaged.
: There are photos here:
: http://postimage.org/image/1gb2ui0lg/
: http://postimage.org/image/2p2rdrs9w/
:
:
: The new looking part is a new part subsequently ordered from HHB. The old
: one with the mangled legs is the cheap failed device.
:
: Is anyone able to tell whether this might or might not be fake?
___________________
Open them up and have a look

Colin

== 3 of 8 ==
Date: Mon, Mar 21 2011 2:53 pm
From: "Gareth Magennis"

"Colin Horsley" <horsley-spam@westnet.com.au> wrote in message
news:DYadnUt9qcE_WRrQnZ2dnUVZ7q2dnZ2d@westnet.com.au...
> "Gareth Magennis" <sound.service@btconnect.com> wrote in message
> news:j7Php.143670$XM7.118285@newsfe18.ams2...
> : Hi,
> :
> : I recently replaced the STK amplifier module in a Genelec speaker.
> These
> : STK modules are not easy to find, but I did find one on the net,
> delivered
> : from the far east, which was a quarter of the price of the official
> spares
> : supplier here in the UK (HHB). I informed the customer prior to order,
> and
> : he was happy to take the much cheaper part.
> :
> : Anyway it lasted 1 day before failing short circuit. Fortunately the
> : drivers are not damaged.
> : There are photos here:
> : http://postimage.org/image/1gb2ui0lg/
> : http://postimage.org/image/2p2rdrs9w/
> :
> :
> : The new looking part is a new part subsequently ordered from HHB. The
> old
> : one with the mangled legs is the cheap failed device.
> :
> : Is anyone able to tell whether this might or might not be fake?
> ___________________
> Open them up and have a look
>
> Colin
>
>
>

One of them is new and is going to be fitted in the speaker. The customer
does still have the original failed device but I don't have it back yet.

I wanted to take a photo before destroying the casing or I would not have
been able to post this thread for external visual i.d..

Gareth.

== 4 of 8 ==
Date: Mon, Mar 21 2011 3:28 pm
From: "Gareth Magennis"

Here's a hi res picture of the opened module:

http://postimage.org/image/2qgigsn38/

What are those things?

Gareth.

== 5 of 8 ==
Date: Mon, Mar 21 2011 3:33 pm
From: Jeffrey Angus

On 3/21/2011 5:28 PM, Gareth Magennis wrote:
>
> Here's a hi res picture of the opened module:
>
>
> http://postimage.org/image/2qgigsn38/
>
>
> What are those things?

My guess? A transistor die (unpackaged)
There's 4 of them, each pair shares a 3-legged
SMT.

Jeff

== 6 of 8 ==
Date: Mon, Mar 21 2011 5:43 pm
From: "Phil Allison"

"Gareth the Menace" ...
>
> Here's a hi res picture of the opened module:
>
> http://postimage.org/image/2qgigsn38/
>
> What are those things?

** Here is the datasheet for the similar STK422-90.

http://datasheets.pl/S/STK/STK442-090.pdf

The 4 output devices are Darlington pairs and the SMD devices in the middle
of each pair are the bias stabilisers. The Darlingtons each have twin
emitter leads soldered to the PCB.

Looks an easy enough to copy the thing - just normal SMD board plus four
power chips on metal headers.

Older versions (made by Sanyo) had no SMD - but instead used transistor
chips and printed resistors directly on the board. They were known as
"hybrids" to distinguish them from regular ICs.

My local supplier ( WES Components) has the STK442-130 listed for A$22.50
each.

Littlediode in Surry offer them for 10 UK pounds + VAT.

.... Phil

== 7 of 8 ==
Date: Mon, Mar 21 2011 6:07 pm
From: "Phil Allison"

"Gareth the Menace "

> Is anyone able to tell whether this might or might not be fake?

** It is rare for anyone to set out to manufacture a "fake" electronic
device for sale - so the terms "fake" and "counterfeit" are misleading.

What IS done is to remove the labelling from a cheap device and re-label
it as another, more expensive and far more sellable type.

In the case of the STK422 series of modules, the game would be to re-label a
lower spec part as a higher spec one.

FFS - buy from a trusted local supplier.

Is 10 UK pounds plus VAT too much for a 65 watt per channel stereo power amp
??

.... Phil

== 8 of 8 ==
Date: Tues, Mar 22 2011 12:35 am
From: "Gareth Magennis"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:8uqb3fFk6rU1@mid.individual.net...
>
> "Gareth the Menace "
>
>> Is anyone able to tell whether this might or might not be fake?
>
>
> ** It is rare for anyone to set out to manufacture a "fake" electronic
> device for sale - so the terms "fake" and "counterfeit" are misleading.
>
> What IS done is to remove the labelling from a cheap device and re-label
> it as another, more expensive and far more sellable type.
>
> In the case of the STK422 series of modules, the game would be to re-label
> a lower spec part as a higher spec one.
>
> FFS - buy from a trusted local supplier.
>
> Is 10 UK pounds plus VAT too much for a 65 watt per channel stereo power
> amp ??
>
>
> .... Phil
>
>
>
>

I did buy this at Littlediode, (First time I've used them). I am now
wondering if they are indeed a trusted supplier. It was shipped (according
to them) from the far east, taking a week or so to arrive.

I woudln't normally do this, as if it is too good to be true then usually it
is.
Hence me buying another one from HHB who I trust implicitly and will have
sourced the part from Genelec.

Unfortunately I paid more for postage from HHB than the entire Littlediode
transaction cost!

Ho hum, and there's me trying to do the customer a favour.

Thanks for the info, when I get the other one back from the customer I shall
break it open for comparison.

Gareth.

==============================================================================
TOPIC: Recommendation for electronics forums?
http://groups.google.com/group/sci.electronics.repair/t/a2a97ca7806d8277?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Mar 21 2011 2:10 pm
From: Franc Zabkar

On Sat, 19 Mar 2011 17:39:54 -0800, David Nebenzahl
<nobody@but.us.chickens> put finger to keyboard and composed:

>I'm looking for an online electronics forum (web-based) where I can post
>some questions.
>
>Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying
>to educate myself here, am working on a project, and a web forum that
>allows one to post pictures would be better for my purposes.

Here in Australia most ISPs offer free web space to their users. I use
my web space to post pictures and other binary data. Is that an option
for you?

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

== 2 of 2 ==
Date: Mon, Mar 21 2011 5:31 pm
From: David Nebenzahl

On 3/21/2011 1:10 PM Franc Zabkar spake thus:

> On Sat, 19 Mar 2011 17:39:54 -0800, David Nebenzahl
> <nobody@but.us.chickens> put finger to keyboard and composed:
>
>> I'm looking for an online electronics forum (web-based) where I can
>> post some questions.
>>
>> Don't get me wrong: I love, and usually prefer, Usenet. But I'm
>> trying to educate myself here, am working on a project, and a web
>> forum that allows one to post pictures would be better for my
>> purposes.
>
> Here in Australia most ISPs offer free web space to their users. I use
> my web space to post pictures and other binary data. Is that an option
> for you?

It's an option I'm already using. Well, not through my ISP, but using
one of the dozens of free photo hosting sites out there. In fact, the
forum I'm using (see below) doesn't let me post pictures directly, so I
have to first post them to a hosting site, then give a link to the
picture in the forum posting. A little cumbersome, but not too bad.

The thing I like about the web forums (I'm using Electro-Tech now, as
suggested above) is that you can post pictures *in your message*. What a
concept! So rather than dicking around with "binary" newsgroups (which I
don't use anymore since I stopped downloading pron), I can post
schematics, etc., right in the message.

As I said, I still prefer Usenet for most online communication. But
these newfangled Web thingies sure have their good points.

--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by

- from Usenet (what's *that*?)

==============================================================================
TOPIC: Oral-b Braun electronic toothbrush problem
http://groups.google.com/group/sci.electronics.repair/t/49caca46fe47e846?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Mar 21 2011 2:32 pm
From: Meat Plow

On Mon, 21 Mar 2011 14:06:06 -0700, William Sommerwerck wrote:

>>> You've said this before. My Sonicares have lasted from two to four
>>> years.And that's buying them in pairs at Costco.
>
>>> You must be recharging them in a way I am not. How often do you drop
>>> them back on the charger?
>
>> In the instructions for my Oral-B's, there is an admonition to totally
>> drain the battery and then recharge: every six months for the "1000"s
>> that I just bought and monthly for the "Vitality" that recently died.
>
> That assumes the user recharges after every use, presumably creating a
> "memory".
>
> I tend to run my Oral-Bs down before recharging them. It's the Sonicares
> that have had a seemingly too-short life.

I keep my Sonic on the charge all the time when not in use. Use it for 2
minutes twice a day. I'm pretty sure i bought it when they first came out
was that 2000 or so?

--
Live Fast Die Young, Leave A Pretty Corpse

== 2 of 3 ==
Date: Mon, Mar 21 2011 5:14 pm
From: "William Sommerwerck"

> I keep my Sonic on the charge all the time when not in use.
> Use it for 2 minutes twice a day. I'm pretty sure I bought it
> when they first came out was that 2000 or so?

That seems about right. Maybe a year or two earlier.

== 3 of 3 ==
Date: Mon, Mar 21 2011 6:05 pm
From: Sylvia Else

On 22/03/2011 12:39 AM, (PeteCresswell) wrote:
> Per Sylvia Else:
>> Buy a new one.
>
> But be prepared for some sticker shock.
>
> The one I had (that just went South couple days ago) cost less
> than 15 USD a couple of years ago.
>
> The cheapest Oral-B I could find retail around here was close to
> eighty dollars.
>
> Finally wound up paying $100 for a two-pack of "Professional
> 1000" models at Sam's Club - figuring that the extra twenty was
> well spent against the day when one failed again.

Perhaps. Have you checked the shelf life of nicads?

Sylvia.

==============================================================================
TOPIC: Running a PC outside of a computer case
http://groups.google.com/group/sci.electronics.repair/t/767389e3dda5bc79?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Mar 21 2011 2:59 pm
From: Baron

D Inscribed thus:

I notice that no one in this whole thread has mentioned taking suitable
precautions against causing damage from static discharge !

--
Best Regards:
Baron.

== 2 of 3 ==
Date: Mon, Mar 21 2011 3:01 pm
From: Meat Plow

On Mon, 21 Mar 2011 21:59:29 +0000, Baron wrote:

> D Inscribed thus:
>
> I notice that no one in this whole thread has mentioned taking suitable
> precautions against causing damage from static discharge !

And in your opinion, this indicates what?

--
Live Fast Die Young, Leave A Pretty Corpse

== 3 of 3 ==
Date: Mon, Mar 21 2011 5:16 pm
From: "William Sommerwerck"

> I notice that no one in this whole thread has mentioned
> taking suitable precautions against causing damage
> from static discharge!

It's implicit. It's assumed anyone who wants to do this knows the routine.

==============================================================================
TOPIC: HDTV has no sound
http://groups.google.com/group/sci.electronics.repair/t/3a7aee93765769fb?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Mar 21 2011 5:07 pm
From: vjp2.at@at.BioStrategist.dot.dot.com

Actually very faint sound at max vol w earphone but effectively silent.

It can't be the speakers because it does the same with two
different"speakers".

AM I right to think it is a capacitor in the amp circuit? The reason I doubt
is it does not respond to hitting/shaking. THe other thing is the faint
sound at high volume doesn't match past experience with amp capacitor
burnout.

THe unit is a Supersonic 7" 193a HDTV with a 12v power adaptor.

PS, is there any "electronics repair rules of thumb" cheat sheet anywhere?

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

==============================================================================
TOPIC: SECRET SEEMS
http://groups.google.com/group/sci.electronics.repair/t/10d332afe33dced0?hl=en
==============================================================================

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