Question about Compaq Presario F572US Notebook PC
I had a faulty AC adapter, so I bought a new on. A new battery too. Tried em and nothing. So I figure the mobo is shot. I get a new one and plug it in. Still nothing. From the title, you can see that the problem isn't the AC adapter or the AC module. What's the next step in the diagnosis? Be aware, I have it in barebones mode. Only essential hardware. -mobo(CPU, Heatsink, all that), power button module, ac module, a stik of RAM,
First is the correct power pack volts and amps and watts
first first first. my guess is 65watt min..(i dont know Compaq volts its too old)
then the Fan must come on or the POWER regs are shot.
a common ***** of mobo cause
why are you fiddling around old junk parts, there is no support for this zero value PC? its only worth $5 used and broken.
your diagnosis false.,sorry.
in electronics if the voltage falls in the 2 lines from the pack.
lets say its a real HP with 19v as most are, (compaq?)
if you plug it in and the volts falls (use a thing called a volt meter and ignore useless LED that glow at 2v, see why?)
then if 19v is say 10vdc NOW, (hard fail that)
that is what? answer is 2 things.
1;bad pack (wrong pack ,weak pack or dead)
2;or the load is shorted,
facts. this is called electronics trouble shooting 101.
and OHMS laws are day 1 learning topics.
did you strip the mobo clean first. ?
there are 2 ways to do this start full and strip or start empty and build.
see this, see the parts pulled? its a complex Elitebook, one of the best made ever. not compaq relics.
we remove all modules 1 by 1, and CPU GPU last.
keep an open mind, use a voltmeter,
the BIOS is dead if cpu is pulled sure. but will still hold power.
the sad thing is seeing folks use LED for a voltmeter.
sorry that is hopeless. (2volts is useless info(@^@)
a Voltmeter DMM is $20 at walmart. buy one and learn to use it.
the PC mobo has regulator on board,
mine converts 19vdc raw to like 5 other key power rails
I have a schematic of my mobo, (rare but have it)
i can probe the rails to see if the regulator is shutting down
they do that on all overloads, all do. (this feature prevents burned up regs. a good thing)
If lucky, one h part removed from the MOBO cures the overload.
we have load bank in our shop
we can load down any power pack made or PSU
and see if it can just full power.
many cant. do to old parts you are buying
or using wrong parts,
with no parts list ?how can you fix any pc,
the parts list tells you the true packs spec, volts,amps/watts.
never assume what it came with it was right , or get FAIL endless.
BTW HP still makes learning correct packs sizes hard.
mine has 4 packs listed, for each faster power hogging CPU and GPU but does not match them up in the service guide.
just shows them. so this can get hard.
In my case only the 100w works, mine max max speed.
Posted on Jun 27, 2017
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Posted on Jan 02, 2017
Hve u tried a differnt adaptor , the adaptor might be blown too ,try replacing the adaptor , also check for the power cord if it has any kinks in it which may be interrupting the power supply , since the adaptor 18.5 v 3.5 a is the most common of all hp adaptors u should find one to try .
Posted on Aug 27, 2008
Have you tried attaching an external monitor when the LCD screen is disconnected from the motherboard? this connector is located under the keyboard strip – a piece of plastic just above the keyboard.
If it works, this way, then the video cable isn’t seated properly in the connector on the back of the screen. Plugging the video cable back in should fix the problem.
I don’t know how comfortable you are with taking apart laptops but I think that this information could be useful for you.
Posted on Sep 28, 2009
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