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Old September 20th 20, 04:37 AM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
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Posts: 1,467
Default Apparent PSU problem

Rene Lamontagne wrote:
On 2020-09-19 4:13 p.m., Larc wrote:
On Sat, 19 Sep 2020 15:50:22 -0400, Bill wrote:

| Sorry, what does PG stand for? Since you said all power levels were
| okay, I'm not sure what a new one is going to do better. You know how
| to do what the start button does directly on the motherboard with a
| screw driver, or other tool, don't you? I assume you tried that too.
| Next, I would look at the owners manual for the motherboard and see
what
| a blinking PG indicates. Sorry, I am not an expert. Good luck!

PG=Power Good. It's an indicator that all power levels (+12V, +5V and
+3.3V) are at
their correct output values. Under voltage protection kicks in and
prevents the PSU
from turning on if there's any variation. This explains it more fully:

https://www.hardwaresecrets.com/ever...protections/2/


Here is one part that explains the need for a PG reading to be OK
before a computer
will start:

"... the under voltage protection shuts down the power supply if the
outputs have a
voltage below a certain level. If the UVP is active when the power
supply is first
turned on, the power supply would never turn on, because voltages are
below the UVP
trigger point. In other words, because when you first turn on the
power supply
voltages are below their values for a fraction of second, the UVP
would prevent the
power supply from being turned on."

The PSU not coming on when UVP is active is a PC thing. When the PSU
is connected to
a tester instead, it will come on even if there are problems.

I'm at least 90% sure the PSU is the sole problem here, but just
wanted some input
from wiser, although likely not grayer, heads if there could be
something I've
overlooked.

Larc


If the PG line, pin 8 was blinking or dim, that would be ample reason
to change out the PSU for a new one, I believe you are doing the right
thing.

Rene


The 5V is probably low on it.

One of my Antecs, it was the +5V output caps that
let out the magic smoke. Other threads mentioned
measuring +5V and finding it abnormally low.
If it gets too far out of spec, eventually it
could cause PowerGood to flip state.

There are *three* Antecs in the junk room, but none
is an exact match for the OPs one. They're all likely
to be ChannelWell builds. The transformer inside will
have "CWT" stamped on the transformer or similar.

There were four caps on mine, split on the top, with
orange-brown juice coming out.

One of those Antecs has a funny flaw - the output is fine,
but on the primary side, the PSU puts "noise on mains", which
other appliances can sense to their detriment. It can cause
my ADSL2 modem to lose sync at 9PM in the evening. So that PSU
earned a membership card to the Junk Room.

Paul