J
jaugustine
Hi,
Regarding that small Dell Optiplex SX260 desktop type computer
that uses an external power supply that won't "boot up". Note: There
is a big difference between this SX260 and a GX260 model.
I checked to see if there was any operating voltage for the P4/2.6Ghz
CPU, and I measured 0V across the "bank" of 2200/6.3V filter caps after
I turned on the power. This CPU requires 1.25V - 1.4V to "run".
I measured +12V at the input of the V regulator(s) which I assume operate
as high speed switches (SMPS), but there was no voltage on the other
leads of those switching regulators in parallel.
Using a "low power" (prevents semi-conductors affecting in circuit
resistance readings) ohms meter, I measured about 5.5 ohms across those
filter caps. After I removed the CPU, I measured about 63 ohms. Of course
electrolytic caps normally have some "leakage" current that will affect the
reading.
It seems to me that the 5.5 ohm reading might indicate a CPU defect?
With the CPU removed, there is still no voltage across those filter caps.
I assume the voltage regulator has been damaged by the CPU?
Thank You in advance, John
Regarding that small Dell Optiplex SX260 desktop type computer
that uses an external power supply that won't "boot up". Note: There
is a big difference between this SX260 and a GX260 model.
I checked to see if there was any operating voltage for the P4/2.6Ghz
CPU, and I measured 0V across the "bank" of 2200/6.3V filter caps after
I turned on the power. This CPU requires 1.25V - 1.4V to "run".
I measured +12V at the input of the V regulator(s) which I assume operate
as high speed switches (SMPS), but there was no voltage on the other
leads of those switching regulators in parallel.
Using a "low power" (prevents semi-conductors affecting in circuit
resistance readings) ohms meter, I measured about 5.5 ohms across those
filter caps. After I removed the CPU, I measured about 63 ohms. Of course
electrolytic caps normally have some "leakage" current that will affect the
reading.
It seems to me that the 5.5 ohm reading might indicate a CPU defect?
With the CPU removed, there is still no voltage across those filter caps.
I assume the voltage regulator has been damaged by the CPU?
Thank You in advance, John