Preliminary Necrosy Report: Power Supply: Lack of Lubrication: Fixed and Dell is Proprietary [COLUG]

[jep200404]

The power supply turned out to be more "interesting" than I expected. 
Read on for the Dell surprises. 

I got no signs of life from the power supply. 

The next thing to check out was the power supply. 
Nudging the blades through the grill, revealed that 
the fan was siezed. I opened up the power supply, 
took out the fan and confirmed that the fan was siezed. 
It was hard to rotate with my fingers. So I peeled 
back the sticker over the hub, put a drop of oil on the 
cheapskate sleeve bearing, and pushed the sticker back 
down. I worked the fan back and forth by hand until 
it rotated almost freely, then applied +12V to the fan. 
It spun, slowly rising in speed until after a few 
minutes, it was back to normal. It made a full recovery. 

----------------------------------------------------------

Back to the rest of the power supply. I was surprised how 
little dust was in it. The stuff inside seemed a bit 
better than in most typical power supplies. 

The power supply has two connectors for the motherboard. 
An ATX _style_ connector and an AT _style_ power connector. 

The pinout on the ATX _style_ connector is completely different 
from regular ATX power supplies. The empirical pinout is: 

 1  Red     +5V
 2  Black   GND  
 3  Red     +5V  
 4  Black   GND  
 5  Orange  +5V   (this is probably the PWR_OK signal)
 6  Purple  +5VSB +5V standby power (low power)
 7  Yellow  +12V   
 8  Blue    -12V   
 9  Black   GND
10  Black   GND

11  /PS_ON  Grey  power supply on (active low (+3.3V while off))
12  GND     Black
13  GND     Black
14  GND     Black
15  -5V     White
16  +5V     Red
17  +5V     Red
18  +5V     Red
19    no pin
20  +5V     Red

Compare that to the standard pinout at 
http://www.hardwarebook.info/ATX_Power_Supply
When Bill Baker gave me his computer, and talked about the 
special Dell power supply, I thought the only difference 
was the extra AT _style_ connector for more power. 
I realize now that it was completely different. 
Using a standard connector in such a non-standard way is nasty. 
Shame on Dell! 

Now I realize that I might have misunderstood a previous Dell 
computer, and maybe I unnecessarily judged it to be bad. 

The AT _style_ connector has the following pinout: 

 1  Black  GND
 2  Black  GND
 3  Black  GND
 4  Blue   +3.3V
 5  Blue   +3.3V
 6  Blue   +3.3V

By the way, there is a date stamp on the power supply: 

   QC08b
   2000. 6. 17
   FOXCONN

The Dell sticker on the power supply says in part: 

   Model: NPS-200PB-73 M Rev: 03
   Output: +5V 22.0A     -5V 0.5A
           +12V 6.0A    -12V 0.8A
           +5VSB 1.2A    +3.3V 18.0A
   MAX.COMBINED POWER ON +5V AND +3.3V OUTPUT
   IS 135W,MAX.COMBINED OUTPUT CURRENT ON -12V 
   AND -5V OUTPUTS IS 0.8A,

--------------------------------------------------------

So I started looking at power supplies in or from other 
Dell computers. 

o  Four of them follow the ATX standard, even the color code, 
   except that pin 18 for -5V is absent. 
   These are from newer computers, so Dell has been drifting 
   towards being more (but not completely) standard. 

o  I knew that one Dell PS from the dumpster was special. 
   It has a 24 pin version of the ATX connector. The first 
   20 pins are standard, with the exception that -5V is absent. 
   Four more pins are added to one end of the connection for 
   more power. This non-standard power connector is interesting 
   in that it _can_ be plugged into normal motherboards, 
   as long as there is no mechanical clearance problems with 
   the four extra pins past the end, and except for the missing 
   -5V supply. Also, the Dell computer that the special power 
   supply came from, _probably_ could work with normal ATX power 
   supplies, although there might be voltage drop on the fewer 
   number of wires. 

o  Another Dell PS has the same very non-standard pin-out as the 
   one from Bill (and is for the same model motherboard that 
   Bill gave me). 

Thanks again to Bill for bringing out his dead. I am learning much.