sci.electronics.repair
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Today's topics:

* Anyone help me with component ID for X5DIJ-SX039C laptop (k501j mobo)? - 3
messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/58fd5bf0893d5f4a?hl=en
* Unsolderable wire? - 20 messages, 9 authors
http://groups.google.com/group/sci.electronics.repair/t/846b59baa6a8b7e9?hl=en
* Need schematic for Gruindig GO-15z scope. - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/a8429eef64636c94?hl=en
* $&*(*%!!! - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/861b6ebf9e4979c6?hl=en

==============================================================================
TOPIC: Anyone help me with component ID for X5DIJ-SX039C laptop (k501j mobo)?
http://groups.google.com/group/sci.electronics.repair/t/58fd5bf0893d5f4a?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Jan 19 2014 4:27 pm
From: Chris from London


Went to try to fix my daughters ASUS laptop and made it much worse :)
She did not have her power supply so I used mine - I have an ASUS netbook. The plug was not the same but the VA are so I rigged up what I thought was the correct one but when I plugged it in it would not light the "PSU connected light". Although the laptop worked, without a charger it was no use.

As it was working before I got my hands on it I assume my connector somehow caused the PSU circuit to blow. The DC Jack goes to a plug on the mobo and I tested it in situ - there was 19v at the mobo socket, so the prob is further down the line.

I had to take the laptop completely apart to get at the mobo components to test points, and cannot easily re-connect everything to test the whole. I stripped it down and sure enough there is a burnt-out component - looks like a SM cap (MLCC) but cannot be 100% certain due to ignorance.

The mobo is an asus k501j

Found the schematic (https://googledrive.com/host/0ByM1ELG0t6mgZlJsRmRZcXhSVWM/pub/asus_k40ij_k50ij_rev_1.1_sch.pdf although it is for rev 1.1 and my board is rev 2.1) so have extracted the PSU Section and added it to the photo.

It looks as if the burnt one is an MLCC - a capacitor but, as I am not sure I have got the right schematic and cannot trace the wiring on the board itself (it is too thick) I guess I can only go ahead and replace it and hope for the best.

Can I test the mobo with nothing apart from power or do I need to reassemble? Can I simply remove the component and see if the laptop works without it? There could be a further fault. Presumably I do not need a MLCC - a regular cap would do it provided it is rated at 25v? Thought I could maybe try to find one on an old computer board as it looks like you cannot easily buy just one MLCC.

Hers a photo of the mobo showing the component and the schematic:
http://i989.photobucket.com/albums/af18/zeus_1066/domtech/laptop/asus-k501j-burnt-out-schemtoo_zps3829aba0.png

Here is a bigger pic of just the mobo:
http://i989.photobucket.com/albums/af18/zeus_1066/domtech/laptop/k501jmoborear_zps25b04b6d.jpg

Any help gratefully appreciated.







== 2 of 3 ==
Date: Sun, Jan 19 2014 5:41 pm
From: "Phil Allison"



"Chris from London"


>Hers a photo of the mobo showing the component
> and the schematic:
>
>http://i989.photobucket.com/albums/af18/zeus_1066/domtech/laptop/asus-k501j-burnt-out-schemtoo_zps3829aba0.png


** What I see your arrow pointing at is a burnt looking SMD tantalum cap
(C6802) and immediately to it's left a missing part - Schottky diode
(D6801). The cap further to the left is an MLCC.

With reverse polarity at the DC jack, the diode would heat, melt the solder
and fall off the PCB - then the tantalum cops reverse voltage and
explodes.

I strongly suspect there is other damage too.



.... Phil







== 3 of 3 ==
Date: Sun, Jan 19 2014 6:40 pm
From: Jeff Liebermann


On Sun, 19 Jan 2014 16:27:11 -0800 (PST), Chris from London
<techt@setzweb.com> wrote:

>Went to try to fix my daughters ASUS laptop and made it much worse :)

Welcome to Learn by Destroying(tm).

>She did not have her power supply so I used mine - I have an ASUS netbook.
>The plug was not the same but the VA are

It's not the power (VA) that needs to be the same. It's the polarity,
voltage, and current rating. The polarity and voltage need to be
exact. The current rating can be higher.

>so I rigged up what I thought
>was the correct one but when I plugged it in it would not light the
>"PSU connected light". Although the laptop worked, without a charger
>it was no use.

So, just buy the correct charger and try it.

>As it was working before I got my hands on it I assume my connector
>somehow caused the PSU circuit to blow. The DC Jack goes to a plug
>on the mobo and I tested it in situ - there was 19v at the mobo socket,
>so the prob is further down the line.

Offhand, I would guess that you applied reverse power. Please check
and compare the polarity markings on the laptop serial number tag and
the charger.

>Here's a photo of the mobo showing the component and the schematic:
>http://i989.photobucket.com/albums/af18/zeus_1066/domtech/laptop/asus-k501j-burnt-out-schemtoo_zps3829aba0.png

I took the liberty of expanding your photo so I could see the
components.
<http://www.learnbydestroying.com/jeffl/crud/asus-k501j.jpg>
The "hole" in the burnt out component is characteristic of applying
reverse polarity to an active device such as a diode. I would guess
that the diode exploded, blowing the top off the epoxy package.

As Phil notes, there could be other damage. I think this is going to
be an uphill battle and a difficult fix. Good luck.

--
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





==============================================================================
TOPIC: Unsolderable wire?
http://groups.google.com/group/sci.electronics.repair/t/846b59baa6a8b7e9?hl=en
==============================================================================

== 1 of 20 ==
Date: Sun, Jan 19 2014 6:12 pm
From: Jeff Liebermann


On Sun, 19 Jan 2014 16:01:53 -0800, Bob E. <bespoke@invalid.tv> wrote:

>> 100% of the RF connectors I use for mountain top radio sites that I
>> deal with are crimped, not soldered.

>This is where the original short length of RG6 was soldered to the pcb
>antenna. It's an inexpensive broadcast TV antenna for home.

Thank you for disclosing what you're trying to accomplish. Context is
always important.

You're going to have corrosion problems. Note that all the
aforementioned crimped connectors have the crimped area sealed inside
the connector. In addition, they are usually wrapped in some form of
waterproofing (i.e. PTFE tape and electrical tape) to keep out the
water. Even if you solder the connections, the capillary action is
going to force the water up the braid and under the jacket. Depending
on the outer jacket slop, corrosion will rot up to several inches of
braid. You can try to seal the braid and solder connections with RTV
silicon rubber that doesn't contain acetic acid but I haven't had much
luck with that.

Using bare wires from the end of a coax cable is about as bad an
impedance bump as you can possibly create. However, it won't matter
for a TV antenna, that has wide bandwidth, but relatively little gain.
PCB TV antennas tend to be rather small, and therefore have even less
gain. Impedance discontinuities will not have a huge effect on
overall performance. Therefore, you can probably just attach some
spade lugs onto the ends of the RG-6/u coax, and use ordinary brass
screws and nuts to make the connection.

>Rather than make a male crimp plus a barrel to join the 2 mailes, just solder
>the long run directly to the pcb. Or so I thought...
>
>I crimped 1/2" of center solid conductor to the braid and soldered the solid
>to the pcb. It seems to work but I have no way to measure any loss. I plan to
>replace this when I find some REAL copper RG6.

If you have a PCB, why not use a PCB mounted F connector?
<http://www.ebay.com/itm/111244951312>
<http://www.ebay.com/itm/261373960762>

I tried to find such a coax cable from my distant past. It had a
copper clad steel center conductor, aluminum foil shield, and a very
loose braid of flash galvanized steel wire braid over the shield. The
braid was only for strength and not for shielding. The zinc plating
was for galvanic compatibility with the aluminum shield. Such a cable
was not intended to be soldered, only crimped. I saw it at STV
(subscription TV) in Smog Angeles in the 1960's. However, I couldn't
find it which suggests that it's either uncommon, not in current
production, or my memory is faulty.

It would be helpful if you could provide any markings on your cable so
that it can be identified.

--
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 20 ==
Date: Sun, Jan 19 2014 8:35 pm
From: Bob E.


> Thank you for disclosing what you're trying to accomplish. Context is
> always important.
>
> You're going to have corrosion problems.

Continuing disclosure: it's indoors, wall-mounted.

> If you have a PCB, why not use a PCB mounted F connector?
> <http://www.ebay.com/itm/111244951312>
> <http://www.ebay.com/itm/261373960762>

It was my call (based on almost no RF expertise) that any solder connection
was much better than the best crimp and that crimps are used strictly for
convenience. I'm beginning to doubt these presumptions...

> It would be helpful if you could provide any markings on your cable so
> that it can be identified.

<http://www.cables.com/Products/92003.aspx>

Thanks.

PS, a police helicopter just flew over the neighborhood at a few hundred
feet. The digital channel I was watching blanked out completely. This at
about 50 miles from the broadcast site, as the crow files (Sutro Tower).





== 3 of 20 ==
Date: Sun, Jan 19 2014 9:01 pm
From: Jeff Liebermann


On Sun, 19 Jan 2014 20:35:10 -0800, Bob E. <bespoke@invalid.tv> wrote:

>> Thank you for disclosing what you're trying to accomplish. Context is
>> always important.
>>
>> You're going to have corrosion problems.
>
>Continuing disclosure: it's indoors, wall-mounted.

Ok. You won't need to deal with anti-corrosion precautions.

>> If you have a PCB, why not use a PCB mounted F connector?
>> <http://www.ebay.com/itm/111244951312>
>> <http://www.ebay.com/itm/261373960762>
>
>It was my call (based on almost no RF expertise) that any solder connection
>was much better than the best crimp and that crimps are used strictly for
>convenience. I'm beginning to doubt these presumptions...

I consider crimping better than soldering mostly because soldering
requires some skill, but crimping can be learned by almost anyone.
With ratcheting crimpers, it is possible to guarantee that the degree
of compression is both sufficient and uniform. Crimp and compression
connectors also will survive the SCTE IPS-TP-401 40 lb pull test,
while soldered connectors often fail this test. In general, crimp and
compression connectors are much better at keeping water out. I've
seen much better reliability after switching to crimp type connectors.
They're also cheaper. I can't think of a single advantage to soldered
RF connectors.

>> It would be helpful if you could provide any markings on your cable so
>> that it can be identified.
>
><http://www.cables.com/Products/92003.aspx>

Bingo. Aluminum braid over aluminum foil shield. You can't solder to
the aluminum. Find a different cable with a copper braid (or use a
connector as I previously suggested).

>PS, a police helicopter just flew over the neighborhood at a few hundred
>feet. The digital channel I was watching blanked out completely. This at
>about 50 miles from the broadcast site, as the crow files (Sutro Tower).

Can I guess(tm)? I don't think the helicopter is large enough to
complete block out the signal unless the TV station signal strength
from Mt Sutro to your PCB antenna is rather weak. That's about what I
would expect at 50 miles with a small PCB TV indoor antenna. Digital
is ummm... digital and tends to deliver either a very good picture, or
nothing. At 50 miles, I would have recommended a bigger, better and
possibly amplified (to compensate for the coax cable losses) antenna.
You might want to check your location with:
<http://www.tvfool.com>
to see if the indoor PCB antenna is adequate, and if a bigger antenna
will be of any benefit. Otherwise, the police helicopter might have
been transmitting video on some frequency to the ground which
overloaded your TV receiver front end.





--
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 20 ==
Date: Sun, Jan 19 2014 9:44 pm
From: "Phil Allison"



"Bob E."
>
> PS, a police helicopter just flew over the neighborhood at a few hundred
> feet. The digital channel I was watching blanked out completely. This at
> about 50 miles from the broadcast site, as the crow files (Sutro Tower).


** Low flying aircraft tend to do that ...

Just like a nearby metal structure causing "ghost" images, they produce
strong reflections of the transmitted signal so your antenna gets two
similar strength signals, one of them delayed by a few microseconds.

This is often enough to seriously corrupt the wanted signal so large amounts
of data are lost.

End result, the pic freezes or pixellates crazily.

Bad luck if you live near a major airport and rely on an off air signal.


... Phil







== 5 of 20 ==
Date: Sun, Jan 19 2014 9:45 pm
From: Bob E.


> I've
> seen much better reliability after switching to crimp type connectors.
> They're also cheaper. I can't think of a single advantage to soldered
> RF connectors.

Of course I agree re. connectors. In my situation the original (short) coax
was soldered to the pcb. I thought that duplicating this connection when
replacing with a longer run of coax was better (re. loss) than introducing
connectors. Soldering F (or other) connectors vs. crimps, I agree: a
nightmare.

Thanks.





== 6 of 20 ==
Date: Sun, Jan 19 2014 9:48 pm
From: Bob E.


> Bad luck if you live near a major airport and rely on an off air signal.
> ... Phil

Just the PD "serving and protecting".

Thanks.





== 7 of 20 ==
Date: Sun, Jan 19 2014 10:48 pm
From: "Michael A. Terrell"



Phil Hobbs wrote:
>
> On 1/19/2014 2:30 AM, Michael A. Terrell wrote:
> >
> > "Bob E." wrote:
> >>
> >>>> When it comes to broadcast TV I try to solder every connection possible.
> >>>> Every crimp is one more dB lost.
> >>
> >> I'm no RF expert, just my impression--possibly mistaken.
> >
> >
> > The loss should be under .1 dB for a good F connector,
> ^^^^^^^^^^^^^^^^
> Jumbo shrimp alert. ;)


There are good ones, but you won't buy them at retail stores.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.




== 8 of 20 ==
Date: Sun, Jan 19 2014 10:53 pm
From: "Michael A. Terrell"



"Bob E." wrote:
>
> > 100% of the RF connectors I use for mountain top radio sites that I
> > deal with are crimped, not soldered.
>
> This is where the original short length of RG6 was soldered to the pcb
> antenna. It's an inexpensive broadcast TV antenna for home.
>
> Rather than make a male crimp plus a barrel to join the 2 mailes, just solder
> the long run directly to the pcb. Or so I thought...
>
> I crimped 1/2" of center solid conductor to the braid and soldered the solid
> to the pcb. It seems to work but I have no way to measure any loss. I plan to
> replace this when I find some REAL copper RG6.


The loss is horrible in copper braided coax at TV frequencies. The
cost is excessive, as well. 'Headend cable' used to be silver plated
copper braided coax, but that was abandoned for foil & drain when
headends passed 216 MHz. That silver plated coax was over a dollar a
foot, in the '70s.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.




== 9 of 20 ==
Date: Mon, Jan 20 2014 2:18 am
From: "Tim Williams"


"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bk38f3Fme1fU1@mid.individual.net...
>> Electroplated wire, most likely nickel.
>
> ** But nickel plated stuff solders beautifully.
>
> Jack plugs and sockets, DC plugs etc.

I have some mil spec, high-temp wire that's nickel plated. Beautiful
stuff, strands wound in layers. It takes an unusually high temperature
and a long time before the solder wets and soaks into it. It does tin,
but I wouldn't say it solders "beautifully", not with ordinary fluxes.

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com






== 10 of 20 ==
Date: Mon, Jan 20 2014 3:38 am
From: "Phil Allison"



"Tim Williams - Wanker & TROLL"


>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated.


** Yaaaawnnnnnnnnnnnnnn....

You have a monstrous, AUTISTIC brain too.............



> It takes an unusually high temperature and a long time before the solder
> wets and soaks into it. It does tin, but I wouldn't say it solders
> "beautifully", not with ordinary fluxes.


** Watch:

https://www.youtube.com/watch?v=73R7eXxjo34

Pure nickel, plated onto brass.

Solders like a dream.

Fuck knows what fucking shit you have.

Asshole .



... Phil








== 11 of 20 ==
Date: Mon, Jan 20 2014 3:43 am
From: Kennedy


On 20/01/2014 7:38 PM, Phil Allison wrote:
> "Tim Williams - Wanker & TROLL"
>
>

Was I the only one to see this predictable response coming & get a
giggle out of it?





== 12 of 20 ==
Date: Mon, Jan 20 2014 3:45 am
From: "Phil Allison"



"Kennedy = Kunt "


FOAD - you stinking autistic MORON












== 13 of 20 ==
Date: Mon, Jan 20 2014 3:46 am
From: Kennedy


On 20/01/2014 6:18 PM, Tim Williams wrote:
> "Phil Allison" <phil_a@tpg.com.au> wrote in message
> news:bk38f3Fme1fU1@mid.individual.net...
>>> Electroplated wire, most likely nickel.
>>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated. Beautiful
> stuff, strands wound in layers. It takes an unusually high temperature
> and a long time before the solder wets and soaks into it. It does tin,
> but I wouldn't say it solders "beautifully", not with ordinary fluxes.
>
> Tim
>

Interesting table:

http://www.efunda.com/materials/solders/solderability.cfm




== 14 of 20 ==
Date: Mon, Jan 20 2014 3:47 am
From: Kennedy


On 20/01/2014 7:45 PM, Phil Allison wrote:
>
> "Kennedy = Kunt"
>
>
> FOAD - you stinking autistic MORON
>

Settle down Phil, one day you're going to blow a gasket! :)






== 15 of 20 ==
Date: Mon, Jan 20 2014 3:50 am
From: "Phil Allison"



"Kennedy = Kunt"


FOAD - you stinking, pig ignorant, autistic MORON








== 16 of 20 ==
Date: Mon, Jan 20 2014 3:52 am
From: "Phil Allison"



"Kennedy"

> Interesting table:
>
> http://www.efunda.com/materials/solders/solderability.cfm


** Shame it is quite wrong.

As anyone with REAL experience of soldering knows.

What is your experience ?

Other than child molesting, that is.













== 17 of 20 ==
Date: Mon, Jan 20 2014 4:33 am
From: DecadentLinuxUserNumeroUno


On Mon, 20 Jan 2014 19:43:02 +0800, Kennedy <kennedy@fakemail.com> Gave
us:

>On 20/01/2014 7:38 PM, Phil Allison wrote:
>> "Tim Williams - Wanker & TROLL"
>>
>>
>
>Was I the only one to see this predictable response coming & get a
>giggle out of it?

T. W. == W & T


Naaaaahhh!!!

He has smarts.




== 18 of 20 ==
Date: Mon, Jan 20 2014 4:35 am
From: DecadentLinuxUserNumeroUno


On Mon, 20 Jan 2014 22:45:27 +1100, "Phil Allison" <phil_a@tpg.com.au>
Gave us:

>
>"Kennedy = Kunt "
>
>
>FOAD - you stinking autistic MORON


You must be Japanese...

Phil Allison == Assholeson Phil

Hardly had to change a thing.






== 19 of 20 ==
Date: Mon, Jan 20 2014 5:30 am
From: JW


On Mon, 20 Jan 2014 22:50:08 +1100 "Phil Allison" <phil_a@tpg.com.au>
wrote in Message id: <bk4grcFu5i0U1@mid.individual.net>:

>
> "Kennedy = Kunt"
>
>
> FOAD - you stinking, pig ignorant, autistic MORON

Do you kiss your mother's quim with that mouth?




== 20 of 20 ==
Date: Mon, Jan 20 2014 5:46 am
From: dave


On 01/19/2014 10:48 PM, Michael A. Terrell wrote:
>
> Phil Hobbs wrote:
>>
>> On 1/19/2014 2:30 AM, Michael A. Terrell wrote:
>>>
>>> "Bob E." wrote:
>>>>
>>>>>> When it comes to broadcast TV I try to solder every connection possible.
>>>>>> Every crimp is one more dB lost.
>>>>
>>>> I'm no RF expert, just my impression--possibly mistaken.
>>>
>>>
>>> The loss should be under .1 dB for a good F connector,
>> ^^^^^^^^^^^^^^^^
>> Jumbo shrimp alert. ;)
>
>
> There are good ones, but you won't buy them at retail stores.
>
>

Use Snap-N-Seal type F-connectors. They are moisture proof and
positively crimp correctly.





==============================================================================
TOPIC: Need schematic for Gruindig GO-15z scope.
http://groups.google.com/group/sci.electronics.repair/t/a8429eef64636c94?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Jan 19 2014 6:26 pm
From: YD


Hi,

I got it from a fleashop, it worked for some time and then stopped. HT
and PSU seem to be OK so I think it should be repairable.

- YD.





== 2 of 2 ==
Date: Mon, Jan 20 2014 12:08 am
From: N_Cook


On 20/01/2014 02:26, YD wrote:
> Hi,
>
> I got it from a fleashop, it worked for some time and then stopped. HT
> and PSU seem to be OK so I think it should be repairable.
>
> - YD.
>

Assuming you mean Grundig, try posting this query, in English, to
de.sci.electronics





==============================================================================
TOPIC: $&*(*%!!!
http://groups.google.com/group/sci.electronics.repair/t/861b6ebf9e4979c6?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 20 2014 5:39 am
From: "William Sommerwerck"


I'd been listening to a Sony SRF-80W (the original FM Walkman) while on the
treadmill. Several weeks ago it developed loud post-volume-control blasting
noises, so I went back to my iRiver.

Two electrolytics were the likely culprits. Yesterday I finally got around to
pulling out the 'scope, to confirm the diagnosis.

Yup. You guessed it.

The blasting was gone. So was the stereo. I adjusted the PLL lock pot (which
I'd done on several samples of this unit, including this one) -- and it
refused to lock. (This is not a critical adjustment. It can easily be done "by
ear".)

Isn't it fun to own classic, high-quality products that stop working -- and
there's no straightforward way to fix them?

Maybe when the weather warms up, it'll start working again. (Nah...)


"We already know the answers -- we just haven't asked the right questions."
-- Edwin Land





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