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Jul 08, 2021, 02:44 AM
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I did the measurements, finally found a solution. You need to short pin5 and 6 as in the photo. The power supply starts. Now I will modify and raise the voltage to 15V.
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Jul 08, 2021, 09:21 PM
Use the 4S Luke
feathermerchant's Avatar
Be wary of exceeding component values at 15V.
Jul 09, 2021, 01:44 AM
Registered User
Yes also not healthy for normal charging of nominally 12V batteries
Jul 09, 2021, 01:46 AM
ancora imparo
jj604's Avatar
Thread OP
John, these are power supplies not chargers.
Jul 09, 2021, 02:09 AM
Registered User
Some people use them to go direct for bulk charging when the voltage output is suitable.

Staying under 15V would be a good idea for most lead chemistries, say charging an AGM in human-regulation mode, prior to heading out to the field,

same goes for LFP 4S, really only needs an HVC no need to sit and watch.

If a noob was trying to get li-ion 4S fully charged, then feathermerchant's warning is especially relevant
Jul 09, 2021, 05:01 PM
Use the 4S Luke
feathermerchant's Avatar
In addition I ALWAYS balance my batteries while charging. It's one of the best ways to find a bad cell.
Balance charging a battery with a bad cell generally takes much longer to complete because of the imbalance.
Jul 10, 2021, 06:50 PM
Registered User
I have 4 supplies and was about to stop lurking and ask about them.

I have most of the pins figured out and now know how to turn them on. Sadly, one has stopped working while I was poking about with my voltmeter. An eBay seller has the matching connector -

Does anybody know how to read out the I2C data? It may help fix my dead-ish supply. I will add my notes in my next post, hope they will help someone.
Jul 13, 2021, 04:31 PM
Registered User
What I have found so far:

The 10 high current output pins
+ + - - -
+ + + - -

the 16 pins on the rear connector:
From the bottom PCB
10 12 14 16
9 11 13 15
2 4 6 8
1 3 5 7

From the back, looking into the connector
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1

What is on those pins:
1 - ??-Signal, CNC7-1
2 - CNC7-7, connector 7 pin 7, 12v when on (not HI-I)
3 - ?? 130mv when on, 100 ohm to gnd
4 - CNC7-13, UC17-9, 4K to gnd, 107mv when on
5 - turn on, 15v when off, CNC7-12
6 - Hi-I -12v, gnd, case
7 - ??-signal, CNC7-3
8 - +12VSB, 0v when off, 2A max
9 - ??-Signal, CNC7-2, 3.3v when on
10 - SCL CNC7-4, goes to an I2C protection chip UC12 (9511A)
11 - SDA CNC7-5
12 - Hi-I -12v, gnd, case
13 - 3.3v, CNC7-11 on all the time
14 - 3.3v, CNC7-10, 0v when off
15 - +12VSB, 0v when off, 2A max
16 - +12VSB, 0v when off, 2A max

??-signal has CLC pi filters on them like the I2C lines. Need to get the scope and logic analyzer out of storage

CNC7-19 is connected to a TP called IOUT, might be useful

CNC11 Fan 1-tach, 2-PWN, 3-gnd, 4- +10v

optocouplers UA13 has 16V and 15V that change to 38.8v and 15V, other side not measured
UA12 has 7.75 and 6.5v that change to 7.58 and 5.42, other side not measured

At this point I lost the 38v and the yellow trouble light blinks.
The conformal coating makes tracing hard enough but this also is a multi layer PCB.
Jul 14, 2021, 07:12 AM
Registered User
Hello.i have a D500E-SO, i have connected your way out to 11.7v but when have to download again. can you guide me?
Sep 01, 2021, 08:59 AM
Registered User

I have a Astec AA23920l with this issue, it works for a few hours or even a day or two, then it shutdown, try to restart a few times and then it power off (this happens with or without a load). I need to plug off the wall for a while and it works again.

Any clue what could be the problem

Thanks in advance
Sep 02, 2021, 04:20 AM
Registered User

DELL AHF-2DC 210W - is OVP disabling possible

Originally Posted by xandrios
Dell Poweredge 6650 (ASTN 7000245) PSU voltage control OVP mod to 16.5V.

Stock OVP(over voltage protection) for the 6650 PSU is around 13.3V.

This simple mod will raise the OVP to 16.5V.

Remove the 5 screws as indicated to remove the back panel.

Locate the leftmost connector on the daughterboard.

Add a 1k resistor in series with the Grey wire.

Voltage will now be adjustable from 3.3V-16.5V(OVP).

There is no UVP on this unit so voltage can be adjusted down to 3.3V at the full 72 amps of current.

I suggest staying below 15.6V as the output capacitors are rated at 16V.

Tested at 15.5v and 72A.

A higher value resistor can raise OVP to above 20V.

The output caps will need to be replaced if voltage goes above 16V !!

Two of these PSUs(at 15.5V) in series(31V) should max out any charger available and will max out most 120V outlets at full power !!

Do this mod at your own risk !!

This i s my first post on the forum - so if I am in wrong thread - please forgive me and point to the right place.
I have been reviewing the forum and have to say I am impressed by the professionalism of people here.

I have just bought this PSU: DELL AHF-2DC 2100W - it is still on the way to me

I have foud the post:
Just one qusestion - what pots should I use (1k / 10k / 100k, prcecise, linear, multi-rotation etc.)?
Any advise would be much appreciated - I am not an expert in electronics and want to make sure not to break / fire something

Also it would be fantastic if someaone knows and can share how to:
- disable OVP on this PSU - would be great to have it working at around 15V
- decrease, perfectly be able to adjust the fan speed with pot (I have read the fans are extreemly loud)
Last edited by Sfinks2; Sep 02, 2021 at 06:36 AM.
Sep 03, 2021, 10:58 PM
Registered User
did you ever find volt mod
Sep 12, 2021, 04:22 AM
Registered User

I have Etasis IFRP-462 power supply units,

Anyone knows the pins to connect or instructions on how to make it run?

Sep 13, 2021, 11:41 AM
Registered User
Does anyone have the 40 or 50mm fan that HP uses it its 750w power supplies?

My friend gave me a RL power supply that he dropped and it stopped working. It just broke off the PS on wire and the usb charger that was added and broke the fan. I got it working last night and it just needs a fan now.

I'll put it apart tonight but a quick ebay search doesn't list any fans separate.
Sep 16, 2021, 07:19 PM
Registered User

How to increase voltage on a HP 643955-201 ( HSTNS-PL19 ) power supply

Hello my friends!

I have one HP 643955-201 ( HSTNS-PL19 ) power supply and i need to raise the voltage to 13.0 volts. I did a lot of research ant the only post with a similar PSU that i found was

But as you can see on my pictures the control board its a little different.

I would be very gratefull if you guys can give me a hand on this.

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