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power supply, or ...?



 
 
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  #1  
Old May 31st 04, 01:03 AM
ynotssor
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Default power supply, or ...?

A borrowed machine was being placed in a new environment for the first time.

The power cable was not fully seated into the power supply on the back of
the machine, and when power was supplied, there was a flash and a pop. Power
was removed from that machine, the cable was checked for damage, the power
inlet appeared normal (although there was the distinct electrical odor for a
while).

The power supply was removed and examined, with no visible signs of damage
or gross electrical odor. A small apparent fuse within the ILSSAN ISP 120S
Rev. C-2 appeared normal, as the small copper strip was continuous and no
discoloration of the glass wall was evident.

After re-assembly, the power indication light on the front of the box does
not light when the main switch is pressed on, nor is there any other type of
system activity.

The question is, please: Is it likely that a simple power supply replacement
will solve the problem, or is it possible that the main switch has been
damaged? I can't find a pinout diagram for the power supply, so don't know
which connectors to test for continuity to the main switch etc. where it
connects to the backplane

A replacement power supply is about US $25, but I wanted to check with the
wealth of knowledge here about what to do or consider before possibly
wasting the money. I'm well aware of the general eMachine opinions and agree
with them, but this box is borrowed.

Thank you.


tony

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  #2  
Old May 31st 04, 05:32 AM
kony
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Default

On Sun, 30 May 2004 17:03:58 -0700, "ynotssor"
wrote:

A borrowed machine was being placed in a new environment for the first time.

The power cable was not fully seated into the power supply on the back of
the machine, and when power was supplied, there was a flash and a pop. Power
was removed from that machine, the cable was checked for damage, the power
inlet appeared normal (although there was the distinct electrical odor for a
while).

The power supply was removed and examined, with no visible signs of damage
or gross electrical odor. A small apparent fuse within the ILSSAN ISP 120S
Rev. C-2 appeared normal, as the small copper strip was continuous and no
discoloration of the glass wall was evident.

After re-assembly, the power indication light on the front of the box does
not light when the main switch is pressed on, nor is there any other type of
system activity.

The question is, please: Is it likely that a simple power supply replacement
will solve the problem, or is it possible that the main switch has been
damaged? I can't find a pinout diagram for the power supply, so don't know
which connectors to test for continuity to the main switch etc. where it
connects to the backplane

A replacement power supply is about US $25, but I wanted to check with the
wealth of knowledge here about what to do or consider before possibly
wasting the money. I'm well aware of the general eMachine opinions and agree
with them, but this box is borrowed.

Thank you.


"Main switch"? If you mean the switch on the front of the case, no,
that's extremely unlikely and impossible given only the problem you
described. I am assuming this is an ATX, not AT, power supply. Ignore
following paragraph if it's an AT.

Take out the power supply, disconnected entirely from system then attach
to it a load (old hard drive) on 5V rail (just plug in the hard drive if
that's what is used) then attempt to power-on power supply by shorting the
PS-On (usually green wire, pin 14) to any ground (black) wire.
http://69.36.189.159/usr_1034/atx_on.gif

If it's an AT, no shorting of the PS-On wire is needed, instead just flip
main front switch.

With either type, after shorting PS-On or flipping swithch the power
supply should turn on, it's fan spinning, and hard drive spinning. If you
have a multimeter then take measurements of voltage at connector.

If power supply won't turn on, consider it dead and try another one. Only
after you have a known working power supply can the rest of the system be
tested to determine if it was ONLY a power supply failure. After a system
has been moved there are other potential problems that might've shorted
out power supply, like a dislodged heatsink, loose wires, a misplaced
motherboard standoff, etc, so examine system interior for any signs of
trouble, double-check all cards, cables, etc. One everything appears
correct, THEN try connecting new power supply with only minimal parts
installed or connected to power and motherboard, that is - CPU, 1 memory
module (or two if RIMMs), video card, heatsink fan.


  #3  
Old May 31st 04, 05:39 AM
ric
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Posts: n/a
Default

ynotssor wrote:

The power cable was not fully seated into the power supply on the back of
the machine, and when power was supplied, there was a flash and a pop. Power
was removed from that machine, the cable was checked for damage, the power
inlet appeared normal (although there was the distinct electrical odor for a
while).

The power supply was removed and examined, with no visible signs of damage
or gross electrical odor. A small apparent fuse within the ILSSAN ISP 120S
Rev. C-2 appeared normal, as the small copper strip was continuous and no
discoloration of the glass wall was evident.

After re-assembly, the power indication light on the front of the box does
not light when the main switch is pressed on, nor is there any other type of
system activity.


1) Is this an AT or an ATX system?
2) If ATX, is the momentary front panel on/off switch being depressed,
or just the AC power on/off switch?
3) Do you have a DVM?
  #4  
Old May 31st 04, 07:34 AM
ynotssor
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Default

"ric" quoted and wrote in message


[...]
ILSSAN ISP 120S Rev. C-2

[...]

1) Is this an AT or an ATX system?


I don't know the answer or even understand the difference. or whether the
question pertains to the computer or just the power supply, nor does a
careful scrutiny of anything on the machine or power supply indicate whether
it's AT or ATX. Does the power supply model number originally posted shed
any clue?

2) If ATX, is the momentary front panel on/off switch being depressed,
or just the AC power on/off switch?


There is just a single front panel switch (depress-button type), and a
115/230V slide selector switch on the power supply itself.

3) Do you have a DVM?


I can certainly borrow or rent one.

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  #5  
Old May 31st 04, 08:29 AM
ynotssor
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Default

"kony" quoted and wrote in message


[...]
ILSSAN ISP 120S Rev. C-2

[...]

Take out the power supply, disconnected entirely from system
then attach to it a load (old hard drive) on 5V rail (just plug in
the hard drive if that's what is used) then attempt to power-on
power supply by shorting the PS-On (usually green wire, pin 14)
to any ground (black) wire.
http://69.36.189.159/usr_1034/atx_on.gif

If it's an AT, no shorting of the PS-On wire is needed, instead just
flip main front switch.

With either type, after shorting PS-On or flipping swithch the power
supply should turn on, it's fan spinning, and hard drive spinning.
If you have a multimeter then take measurements of voltage at
connector.

If power supply won't turn on, consider it dead and try another one.


Thanks, the pinout diagram matches the connector I have. Just shorting pin
14 to the adjacent COM doesn't cause the power supply fan to start, so in
the current absence of a VOM I'll just consider it dead. I didn't have a
spare drive to attach at this time, but it doesn't seem absolutely necessary
at this point. (?)

http://auctions.searchmarketing.com/...42004-1-s.html here I come. If
I then discover larger or more prevasive problems then I'll just replace the
whole box with some $350 2.8GHz Celeron w/ 40GB drive, and salvage the
drives and miscellaneous components for other boxes. I'm sure the owner
would be pleased, as this was just a 333MHz and 2.1GB drive containing a
clean OS install.

I'll follow your helpful advice for the remaining diagnostics, and thank
you.


tony


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  #6  
Old May 31st 04, 10:28 AM
kony
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Default

On Mon, 31 May 2004 00:29:45 -0700, "ynotssor"
wrote:


Thanks, the pinout diagram matches the connector I have. Just shorting pin
14 to the adjacent COM doesn't cause the power supply fan to start, so in
the current absence of a VOM I'll just consider it dead. I didn't have a
spare drive to attach at this time, but it doesn't seem absolutely necessary
at this point. (?)


Some power supplies will not turn on long enough to be noticable without a
load, such as a hard drive. Without the load you can not be sure of
anything. "Usually" an optical drive would work instead, would typically
be a less valuable drive and not the risk to the data.



http://auctions.searchmarketing.com/...42004-1-s.html here I come. If
I then discover larger or more prevasive problems then I'll just replace the
whole box with some $350 2.8GHz Celeron w/ 40GB drive, and salvage the
drives and miscellaneous components for other boxes. I'm sure the owner
would be pleased, as this was just a 333MHz and 2.1GB drive containing a
clean OS install.

I'll follow your helpful advice for the remaining diagnostics, and thank
you.


From above link it seems to be an eMachines' power supply?
If so, I'd replace with 180W Fortron/Sparkle though the mATX sized units
are all pretty similar, the worst choice being a generic.
  #7  
Old May 31st 04, 10:30 AM
kony
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Default

On Sun, 30 May 2004 23:34:18 -0700, "ynotssor"
wrote:

1) Is this an AT or an ATX system?


I don't know the answer or even understand the difference. or whether the
question pertains to the computer or just the power supply, nor does a
careful scrutiny of anything on the machine or power supply indicate whether
it's AT or ATX. Does the power supply model number originally posted shed
any clue?

2) If ATX, is the momentary front panel on/off switch being depressed,
or just the AC power on/off switch?


There is just a single front panel switch (depress-button type), and a
115/230V slide selector switch on the power supply itself.


Based upon your comment that the connector matched the picture I linked,
it is ATX, not AT.
  #8  
Old May 31st 04, 07:53 PM
ric
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ynotssor wrote:

1) Is this an AT or an ATX system?


I don't know the answer or even understand the difference. or whether the
question pertains to the computer or just the power supply, nor does a
careful scrutiny of anything on the machine or power supply indicate whether
it's AT or ATX. Does the power supply model number originally posted shed
any clue?


A) An ATX case has only 7 (max) expansion card slots.
B) An ATX case has a ~2" x ~6" slot above the 7th expansion slot.
C) An ATX case has a low current, momentary SPST on/off switch on the
front panel, which connects to the motherboard (not to the PS.)
D) An ATX power supply will have one 20-pin (two rows of ten) connector
to the motherboard.
E) An ATX case will have its keyboard and mouse connectors as part of
the above described ~2" x ~6" slot in the case. No separate holes.

2) If ATX, is the momentary front panel on/off switch being depressed,
or just the AC power on/off switch?


There is just a single front panel switch (depress-button type), and a
115/230V slide selector switch on the power supply itself.


I'm assuming that this is a momentary type switch, and that this is
an ATX system.

3) Do you have a DVM?


I can certainly borrow or rent one.


When you do:

When your system fails to start, what is the voltage on pin 9? If it is
less than 4.75v, either a) the logic on your motherboard is shorting
b) your +5vsb is under powered, or c) your PS is bad. It is
most likely a combination of b) and c).

If your +5vsb is OK, measure pin 14 of the PS/MB connector. If it is 0.8v
(and the +5vsb is OK), the power supply should be on. If pin 14 is 0.8v,
the +5vsb is OK, and the PS is OFF, the PS is bad. If pin 14 is 2.0v, the
power supply is being told to stay OFF by the MB. If depressing the front
panel ON/OFF switch does NOT lower pin 14 to 0.8v (and the +5vsb is OK),
then the problem is NOT the power supply, but rather MB related.

To test the ATX PSU:

First, disconnect everything from the power supply (including MB.) Plug
AC cord into the rear of the PS. IF the PS has its own rocker on/off
switch, turn it ON. There should be +5v on pin 9 of the 20 pin connector
(+5vsb, usually a violet wire.) There should be 0.8v on pin 14 (PS-ON,
usually a green wire.) This is from an internal pull-up to the +5vsb.

Connect PS power leads to 1 or 2 IDE HDs (for a load). Jumper pin 14
(PS-ON) to pin 13 (ground, black wire.) At this point, fan in PS should
start spinning, drives should spin, and + 5/12v, -5/12v, +3.3v, and
+5vsb should be present at 20 pin connector.

Disconnecting pin 14-13 jumper should turn supply back off.

Good luck.
  #9  
Old June 1st 04, 01:06 AM
ynotssor
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"kony" wrote in message


Some power supplies will not turn on long enough to be noticable
without a load, such as a hard drive. Without the load you can not
be sure of anything.


I now have a functional harddrive that produces the same results when
connected and pin 14 is jumped to COM.


tony


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  #10  
Old June 1st 04, 01:12 AM
ynotssor
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"ric" wrote in message

To test the ATX PSU:

[...]
Good luck.


Thanks for the detailed diagnostics. When an IDE drive is attached and pin
14 is jumped to adjacent COM, neither the power supply fan nor the drive is
activated.

I'll look at the voltage details on the various pins when I can get my hands
on a meter. A replacement power supply is on the way.

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