RH1448Y - trying to fix server PSU, C&D Technologies/Murata Power Solutions

[arekm]

Hi.

I'm trying to run HP RH1448Y server PSU (12V, 138A, 1.6kW) outside of the server.

PSU contains two internal fans. First fan (the one in middle) starts immediately. Second fan is supposed
to start when PSU is signalled to start providing 12V output. Both fans are not damaged and working fine
from external 12V and also working when swapped.

Now the fun part:
- if fan2 (the one from the edge) is connected then output 12V drops to 3-4V and fan2 doesn't start
- if fan2 is disconnected then output 12V is stable (was drawing ~50W from output without a problem)
- if fan2 is disconnected then PSU reports fan failure through I2C interface (but 12V is stable)
- if I reconnect fan2 then 12V drops to 3-4V and I2C reports "Primary Overtemperature" or "Secondary Overtemperature" (sometimes primary, sometimes secondary) which is obviously not true since everything is cold (didn't get a change to overhead, too short period)
- NTC (for secondary) and diode (for primary) are used to measure temperature and look to be fine


So the question is - what could be wrong with fan2 driver causing such errors/problem? Not even sure what exactly drives it. PCB tracks hide under heatsink near output connector (and dismanting it is going to be really hard).

I don't see any part being damaged, capacitors look fine, no obvious shorts on capacitors.

Maybe someone worked with such type of PSU and had similar problem... unlikely but well.

Note, this PSU was made by C&D Technologies which is Murata now. Unfortunately Murata support
didn't even bother to answer.

ps. on some photos one heatsink was desoldered to see what is under

[NiHaoMike]

What happens if the first fan is disconnected but the second fan is connected?

[arekm]

In such case the output also goes down from 12V to 3-4V and PSU reports fan1 failure and overtemperature condition.

If I disconnect both fans then PSU reports fan failures, general failure but provides stable 12V.

[Knightmare80]

Hello,
maybe you can Help me.
1. You found our error?
2. I want to build a Mining Rig and Buy some of this RH1448Y from a Friend.

My Question are, how to Start the PSU and maybe you know about the Terminal 12V and 3,3V Output?

Thanks for Help.

regards,Karsten from germany

[arekm]

Wasn't able to fix the issue (and Murata company is useles - they don't even answer).

Read http://www.murata-ps.com/data/acdcsupplies/cps_d1u4-w-1600-hx.pdf for all information.

[robots]

Where did you find specification for the i2c ? I have HP DL580 psu, and i am interested what information can i get from it.

[arekm]

www.murata-ps.com/data/apnotes/acan-31.pdf

[qbeusz]

Hi,
Can anyone tell me, how to power up this PSU?
I have information about "Main Output Absent", and on +12V pinouts, I have 0V.

Thank you

[snickers]

To start PSU you need to down PS_ON only after AC_OK rised.