Re: Asus Cusl2-c and a problem with VR

In article <20060408115518.119B.0.NOFFLE@localhost-local>, winyl
<winyl@xxxxxxxxx> wrote:

Thanks for advice Paul.

I have checked the mobo visually.There are no burns, no capacitor caps
are poped up nothing has leaked.I do not have capacity meter to measure
them :(
Toroids and other small elements are not burned.Mofset chips are
conducting current one way.Could Check only that with my electronic
multimeter.
Aha and I have Intersil 6021ACB on the mobo.
I have checked the voltage on the toroid with is close to dip switches
and it reads 3.47.Is it powered thru the Intersil.I think it is.
On the spec sheet there is a statement that is shuts down all the lines
in case of voltage faults.
So the line Vout1 is not powered.This are the readings I've got
Vsen2 0,45V
Vsen4 0,00V
Drive2 0,17V
Pgood 0,01V
Fault/RT 10,74V
think is should be 12V in case of fault compared to spec.(line about
driving this out to Vcc in case of fault.) Vcc is 11,97V though.Did not
check the other side of the chip because I still have the heatsink on.

Any idea?

Sebastian

By using an archived copy of the Intersil web site, it is possible
to figure out the URL of the datasheet:

http://web.archive.org/web/20011205222151/www.intersil.com/design/Parametric/productendpoint.asp?cn=239

I got the datasheet for the 6021ACB from here:

http://www.intersil.com/data/FN/FN4/FN4793/FN4793.pdf

The 6021ACB is one PWM and three linear regulators. The PWM powers
Vcore on the processor. PDF page 3 shows a typical application.
The processor really shouldn't be at 3.47 volts for Vcore, but
some lower number. The node where Lout1 and Cout1 meet, is where
you would measure the voltage, and Cout1 could well be a bunch of
capacitors running in parallel.

There are three linear regulators, and the voltages are Vagp, a 1.5V
and a 1.8V source. The 1.8V could have something to do with GTL I/O
voltages for the chipset area.

If you were really measuring Vsen2 and Vsen4, they should have the
real output voltages on them, and not 0 volts and 0.45 volts.

PGOOD is open collector. It is zero volts when "power is bad", and
some higher voltage when power is good.

FAULT "is internally pulled to VCC" when there is a problem, and
your 10.74V says there is a problem.

So, it does appear to be shut down, but the trick will be figuring
out why. And without a separate fault signal per output channel,
you won't know which of the four outputs has detected a problem.
The PWM would certainly be a prime candidate, as that circuit would
have more stresses than the others. A storage oscilloscope might
allow someone debugging the circuit to observe the initial
attempts of the 6021ACB to start, while using a multimeter (all
that I've got) would make the operation of the device for the
first 1 second after power up, impossible to observe.

So your task is a tricky one.

Good luck,
Paul
.

Relevant Pages

  • Re: Capacitor coupling question
    ... that may be a few volts. ... the signal voltage on the FET gate in your example will swing below ground ... steady voltage accross the capacitor with no signal present. ... direction raising 3 volts to 3.5 and back to 3. ...
    (sci.electronics.basics)
  • Re: Where are all the ESR meters?
    ... pair of diodes to discharge the test capacitor ... common glass diode and/or a 1/4-watt resistor? ... comparator, if it is more then a few volts, have a indicator displayed to ... I think it would be far better to make a current source and voltage ...
    (sci.electronics.design)
  • Re: Where are all the ESR meters?
    ... pair of diodes to discharge the test capacitor ... common glass diode and/or a 1/4-watt resistor? ... comparator, if it is more then a few volts, have a indicator displayed to ... I think it would be far better to make a current source and voltage ...
    (sci.electronics.design)
  • Re: Capacitor coupling question
    ... that may be a few volts. ... the signal voltage on the FET gate in your example will swing below ground ... steady voltage accross the capacitor with no signal present. ... direction raising 3 volts to 3.5 and back to 3. ...
    (sci.electronics.basics)
  • Re: Broken Cheap 400W Power Inverter
    ... As it failed, the fault ... light and beeper came on indicating a fault and the input voltage was ... Also I don't know if a battery charger was ... connection at the unit read 12.3 volts with no load and 10 volts after ...
    (sci.electronics.repair)