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Apr 16, 2011, 01:12 PM
Steven
xandrios's Avatar
What model PSU do you have or plan on using? The values are different on both. Also it is best to use a linear taper pot to make the adjustment. I use a 20 turn 50k pot to aquire the general range and then fine tune it from there.
Last edited by xandrios; Apr 16, 2011 at 03:31 PM.
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Apr 16, 2011, 02:18 PM
Steven
xandrios's Avatar
These values should help.
Resistance between pins D3 and D4 to get:

JD200 model PE6800 PSU
960Ω = 13.6v
750Ω = 13.8v
570Ω = 14.0v
460Ω = 14.2v
So basically any pot from 1k to 10k in series with a 460Ω resistor to avoid OVP. The higher value pot gives a greater range in voltage adjustment.
OVP starts at around 14.3v

KD175 model PE6800 PSU
165Ω = 13.6v
122Ω = 13.8v
120Ω = 13.83v. This is the simplest setting as 120Ω is a common resistor value.
OVP starts at around 14v
Last edited by xandrios; Apr 17, 2011 at 01:21 PM.
Apr 16, 2011, 02:55 PM
just look at it smokin'
z-matrix's Avatar
hey

i did that a few times too for fun, just tear out unnecessary components

and rearrange the output feedback loop to 13.8V and set up a current limit foldback at 10A,
now i have a 10A 13.8V CCCV car battery charger.

Z

Quote:
Originally Posted by Dreamglider
When i bought my multiplex easy star, it came with a 12v battery charger, i had a wall type psu rated at 4amps (what the charger needed) but it is to small the charger stopped the charging process as soon as it started.










Works nice but i did not use any load resistor on the +5v line but it works !

top posts: -5v 0.5a | -12v 0.8a
bottom posts: Ground | +3.3v 14a | +5v 30a | +12v 12a
top led is green for ON, bottom is red for Standby
Apr 16, 2011, 06:51 PM
Registered User
Quote:
Originally Posted by xandrios
These values should help.
Resistance between pins D3 and D4 to get:

JD200 model PE6800 PSU
960Ω = 13.6v
750Ω = 13.8v
570Ω = 14.0v
460Ω = 14.2v
So basically any pot from 1k to 10k in series with a 460Ω resistor to avoid OVP. The higher value pot gives a greater range in voltage adjustment.
OVP starts at around 14.3v

KD175 model PE6800 PSU
155Ω = 13.6v
112Ω = 13.8v
OVP starts at around 14v
Hi Xandrios,

I was looking at the pin out chart you provided on the Poweredge 6800 PSU and found a power supply for this model: intel sr6850hw4, which is the third model listed on your pin out picture:

INTEL AHW6UPWR 1570 WATT POWER SUPPLY

Do you know if the info listed above would be the same for this PSU? Thanks
Last edited by MUDSUX; Apr 16, 2011 at 07:09 PM.
Apr 16, 2011, 07:54 PM
Steven
xandrios's Avatar
That particular model is for an SR6850HW4/M. It is the same as the Poweredge 6800 and is made in Thailand. So its the KD175 model. It also has the 3 internal fans. So that would mean 112Ω for 13.8v. This PS is pretty big but it pumps out lots of power. I'll update with more resistance values soon.
Apr 16, 2011, 09:16 PM
Registered User
Quote:
Originally Posted by xandrios
That particular model is for an SR6850HW4/M. It is the same as the Poweredge 6800 and is made in Thailand. So its the KD175 model. It also has the 3 internal fans. So that would mean 112Ω for 13.8v. This PS is pretty big but it pumps out lots of power. I'll update with more resistance values soon.
Thanks! I am pretty excited about the 6800 after reading your report. I will be getting it in a few days. I am sure I will be asking you some more questions when it comes in. Thanks again.
Apr 17, 2011, 07:45 AM
Steven
xandrios's Avatar

Poweredge 6800 PSU


Just a heads up. This power supply has a C20 inlet as described in the attached jpg. Do you have the correct cord? Or do you plan on soldering the wires directly to the PSU?
Apr 17, 2011, 07:57 AM
Registered User
Quote:
Originally Posted by xandrios
Just a heads up. This power supply has a C20 inlet as described in the attached jpg. Do you have the correct cord? Or do you plan on soldering the wires directly to the PSU?
I have no idea, it's not here yet. It was advertised as new and unused but I seriously doubt it will come with a cord. I'll let you know when it gets here. Thanks for the heads up and the pic.
Apr 17, 2011, 01:31 PM
Steven
xandrios's Avatar
I've tweaked the voltage resistance values for the KD175. A value of 120Ω will set the voltage to 13.83v. It's a common resistor value and makes it easy to set the voltage permanently. So Brown-Red-Brown.
Apr 17, 2011, 04:51 PM
Registered User
I bought one of these HP Part# 337867-501 power supplies.

I tried loads from 1.5 to 9 amps wired to the Right side +12V posts P5 & P7 and -12V to the P6 & P8 posts only.

The more amps I pull, the lower the +12 volts goes, from about +12.25 down to about 11.0 volts. Should I connect All Four +12v & four -12v posts together to share the load equally , in order to have it regulate the output voltage to +12.2 volts?

Also, if I were to connect an adjustable potentiometer between the C4 (+12V RMT SENSE) pin and the C5 (+12V RMT SENSE RETURN) pins at the load, shouldn't that allow me to adjust the output +12V to as high an output voltage as possible before the internal circuit design causes a high voltage fault?

(ie. If the sense voltage from the pot is 12.2 volts when the actual voltage across the load is 13.8 V)

Thanks.
Apr 17, 2011, 05:50 PM
Registered User
I used these #10 guage wire female connectors I bought at Auto Parts or The Shack instead of an expensive custom 115 VAC connector >>>

(I had to spread their contacts open with a screwdriver to be able to force them over the Power Supply AC input blades)
Apr 17, 2011, 06:05 PM
Steven
xandrios's Avatar
Hey dan9mar,

I don't think your supply should be dropping out of regulation like that. You can try connecting all four posts together. If this doesn't solve the problem you might have a bad PS. Just be sure to check that your pson and pskill are connected to ground.

Also, post 470 in this thread will answer all of your questions about voltage adjustment + some extra stuff.

I've also used those female spade connectors without any problems.
Apr 18, 2011, 10:55 AM
Dale Kramer
KiloOne's Avatar

7000245 Pinout


Hello Xandrios,

I am looking for the 5v output on the 7000245.

The nameplate says there is 2amps there but it is listed as 'sb', do you know what the 'sb' means?

[EDIT] I found 5v as shown in the attached image and loaded it to 1 amp with no appreciable voltage drop, still don't know what the 'sb' means. I had the wrong ground originally and couldn't find the 5v. There are probably more 5v pins that can be drawn from but a lot of 5v pins can't be loaded.

Thanks
Dale
Last edited by KiloOne; Apr 18, 2011 at 12:01 PM.
Apr 18, 2011, 03:44 PM
Registered User
sb = standby, the voltage that is supplied even when the comp/psu is put to sleep.
Apr 18, 2011, 04:38 PM
Steven
xandrios's Avatar
Yeah. Those are 2 of the primary 5vsb pins. Top row and 4 to the right is the other. With the power off, just check for full continuity between the pins you've already found and other pins. This will give you all the pins on that rail.

The sb stands for standby. It means that the 5v will be available in all modes of operation. Powered up, powered down(standby) and during a fault condition.

Bringing that up, this is the method I used to find the correct pins to power up this supply. It also works for a majority of PS units out there.

With power off and testing each pin to ground.

1. Exclude any pins that are common to each other(including ground pins). Usually these are the 3v and 5v rail pins. They also show the same resistance.

2. Exclude any open pins(pins with no resistance that don't connect to anything).

3. Exclude any pins with a value below 1k ohms and above 10k ohms. From my experience, I've found that the pson and pskill resistance usually falls between a 1k and 10k range.

With power on.

4. Exclude any pins that show no voltage.(pson and pskill are held partially TTL high or just not grounded. So they show some voltage on them).

This will usually leave between 4-6 pins.

Use a .5k ohm resistor on each of the individual remaining pins and connect each to ground. The power supply will usually power up at this point.

Disconnect one resistor at a time from ground.

If the PS remains on after a you disconnect a resistor from ground, then the remaining pins contain the pson and pskill. So keep it disconnected from ground.

If the power supply turns off, then the disconnected pin is either the pson or pskill. So reconnect it to ground.

Repeat this process until you find the pson and pskill pins.

In some cases the PS will turn on with a fault.

If this happens then disconnect one resistor(pin) at a time from ground to find the one that is causing the fault. Then continue with the process above to find the pskill and pson pins.

Even with the 32 pins on the Poweredge 6800 PS, I was able to narrow it down to just 5 pins before I even tried to power it up. It took just under 20 minutes.

These two pictures help to understand how PS On and PS Kill work.
Last edited by xandrios; Dec 29, 2011 at 09:00 AM.


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