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(Nearly) dead Gateway laptop...

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Dave

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Oct 28, 2010, 10:41:01 AM10/28/10
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Appears (to my eye) to have a faulty voltage regulator on the motherboard,
but where? 19.5 VDC input from the AC adapter, but only 1VDC (slightly less
actually) available at the Power On switch (which I would expect to have at
least 5 VDC). Anybody have any idea how power is handled for these
critters? Model 305CRV. Can get SN if necessary. I somehow expected to
find something like a LM317, or at least a couple of 7805/7905 combinations.
Shows what I know about laptops. Any help is appreciated...

Thanks,

Dave


ne...@jecarter.us

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Oct 28, 2010, 6:13:08 PM10/28/10
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I would expect some type ofswitch mode power supply - they're
available as a single chip with minimal external components. Much
more efficent than the 'room warmers' like the LM317/78xx devices.

Check for questionable electrolytic capacitors - a dead one can kill
the switch mode power supply.

SMPS don't like caps with high ESR either - probably easier to replace
than to test.

John

Dave

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Oct 29, 2010, 6:00:00 AM10/29/10
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<ne...@jecarter.us> wrote in message
news:35tjc6tsnd10o406d...@4ax.com...

Hey, THANKS John. I will definetly check this out. Much appreciated.

Dave


Dave

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Oct 29, 2010, 2:11:31 PM10/29/10
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"Dave" <db5...@hotmail.com> wrote in message
news:uoWdneOp9omtBlfR...@posted.internetamerica...

Hey John, took a look at the motherboard again with no (obvious) luck. One
question: would the there be a SMPS on the motherboard, in addition to
whatever is in the AC adapter? I have the voltage from the AC adapter
coming into the board, but it does not appear to be "processed" into
anything like a 5V supply for the digital logic to operate with. It seems
to simply drop to the 1VDC level I mentioned earlier. I feel like I ought
to be able to locate the source of the trouble, but haven't been able to do
so.

Thanks,

Dave


Baron

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Oct 29, 2010, 3:31:39 PM10/29/10
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Dave Inscribed thus:

There are maybe half a dozen SMPS in a laptop ! You need to trace the
19V to find out where it goes. Not at all easy, even if you have a
circuit diagram !

--
Best Regards:
Baron.

Dave

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Oct 29, 2010, 4:36:51 PM10/29/10
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"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
news:iaf7bl$u5s$1...@news.eternal-september.org...

Wow. Give or take a half dozen potential sources of such trouble. Or other
trouble. Okay. And, yeah, to the observation that tracing this path is not
easy. Man. sigh Well, thanks for the reality check. :) Much
appreciated.

Take it easy...

Dave


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