Delta DPS-400GB-1A Troubleshoot (xserve)

[Toasty]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

85° cap from RS is not correct.

Now you've got it working, do them all with the correct types. You'll never have to touch it again.

Toast

[m5mdd]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thx for the thread. m trying to repair same supply. Changed 22uF cap still didn't work.
Will try to replace all cap and see...

[snandu13]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Can anyone help to troubleshoot smps used in HP54501A ? The fuse in the input voltage selector blows up. I checked MOV, Bridge and input capacitors 680mfd /200v ( 2 in series ) appear ok. This uses TIPL755A . This smps model design is very old and perhaps designed in 1980s. Pls help. My mail id is snandu13@gmail.com

[IgorSinelnikov]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Maybe someone can help me. I'm trying to repair one power supply and I'm getting only 100-100 DC across +/- on the rectifier. The standby output voltage is around +2.7V instead of +12V. Where should I start digging? Anyone got schematics?

[ben7]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Maybe someone can help me. I'm trying to repair one power supply and I'm getting only 100-100 DC across +/- on the rectifier. The standby output voltage is around +2.7V instead of +12V. Where should I start digging? Anyone got schematics?

What AC voltage is the rectifier getting? Either the bridge rectifier is bad, or the NTC might be bad.

This psu has PFC in it, so check the voltage across the big filter cap too.

[IgorSinelnikov]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thanks for your reply. Rectifier is getting ~115-120 AC. I'll check other things later and report back. Sorry for a dumb question. What is NTC?

[IgorSinelnikov]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

sorry again. I assume NTC is a thermistor - I'm bad with abbreviations and english terms in electronics in general.

[c_hegge]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Yup. The NTC is indeed the thermistor.

[IgorSinelnikov]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thanks for replying. I was able to repair 4 out 5 PSU's so far. One is giving me a bit of headache. The rectifying bridge was damaged and the caps around the small transformers were bad too. So, I replaced the rectifier and caps. Btw, here is the list of caps that you usually want to replace to fix these PSU's and their nominal values:
C907 - 100uF x 35V
C10 - 47uF x 50V
C909 - 22uF x 25V
C350 - 1uF x 25V
C901 - 100uF x 35V
C900 - 100uF x 25V
C903 - 47uF x 16V
C905 - 10uF x 25V
C353 - 100uF x 25V
Now, this PSU gives a nice buzz in the standby mode and +12.16V output.
The problem is that the xserve shut itself off after ~1.5-2 seconds when I put the PSU into it and push the power-ON button. Is there a "power good" signal in these PSU's? I would appreciate any help with this issue.

[ben7]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thanks for replying. I was able to repair 4 out 5 PSU's so far. One is giving me a bit of headache. The rectifying bridge was damaged and the caps around the small transformers were bad too. So, I replaced the rectifier and caps. Btw, here is the list of caps that you usually want to replace to fix these PSU's and their nominal values:
C907 - 100uF x 35V
C10 - 47uF x 50V
C909 - 22uF x 25V
C350 - 1uF x 25V
C901 - 100uF x 35V
C900 - 100uF x 25V
C903 - 47uF x 16V
C905 - 10uF x 25V
C353 - 100uF x 25V
Now, this PSU gives a nice buzz in the standby mode and +12.16V output.
The problem is that the xserve shut itself off after ~1.5-2 seconds when I put the PSU into it and push the power-ON button. Is there a "power good" signal in these PSU's? I would appreciate any help with this issue.

A buzz you say? Sounds like a primary filter cap is bad, letting loads of ripple into the system, causing it to shut off.

[IgorSinelnikov]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

All the repaired and working PCU's buzz the same way in stand by mode, - I think it's normal.
I'm not talking about anything loud though. I'll try to replace the big cap and see what's gonna happen.

ps. I accidently ripped off one small transformer T3 on one of the power supplies. Does anyone (with this PSU open) have an idea where I can find a replacement?

[laforge]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

I'm also experiencing problems with this power supply.

However, much to the difference to the original posters, I think the small switching power supply for supplying the control logic is working fine. I get the 'buzzing' sound, and I can clearly measure a stable and clean voltage on the capacitors on the secondary side of the small transformer.

Just for the sake of completeness, I've replaced all capacitors on the board, with the exception to the large primary filtering cap (390uF / 450V) and the 1000uF / 2200uF filter capacitors on the 12V side.

There is no output at all on the 12V rails, not even some kind of noise.

The primary-side filter capacitor is fully charged to about 400V, and there is no visible ripple.

The large transformer seems completely idle. I cannot detect any 'riging' when trying to couple into the scope probe (as described earlier in this thread).

I've confirmed that the two large MOSFETs on the primary side get a stable gate voltage, i.e. there is no actual switching going on.

The fuse was not blown. There was no visible damage to any of the parts.

I've measured the protection diodes of the MOSFETs and the rectifier on the primary side, everything looks fine.

I suspect for whatever reason the control logic is not actually enabling the large/main transformer switching.

Does anyone have an idea what I could test next? I've measured at the optocouplers on the separate/stacked controller board, and they also only receive DC voltage levels, not any waveforms. I'm not really sure how the main mosfet's are driven, thoguh.

Thanks in advance.

[laforge]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

A couple of more findings:

* the MOSFET driver IC1 (TC428) has steady low at IN_B and OUT_B
* the transformer T3 through which the mosfet driver is triggered has no signal on either the primary nor the secondary side (confirmed with scope)
* the relay is clicking immediately when AC power is connected (i forgot to mention this in the last post)

a separate question for those who worked with this PSU before:
* did you need to connect the fans to make it power up (there could be some protection circuitry)?

Thanks,

[crm7290]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Hey guys, I have about 15 or so of these power supplies that have gone bad taking as many xserves out of service at the same time. I have found all of the bad power supplies and was wondering how hard it would be to get these working again. I have no real knowledge of this type of circuitry outside of what you learn in college physics classes, but I am willing to learn how to do it if only to get these systems back up and running again. Any help would be appreciated.

[ComputerPro2000]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thank you mcnaryxc, of post #19. One of my dead power supplies also kicked into standby when I tried your same method. That particular run of power supplies seems to go bad often at that location. Now all I need to do is find the pinouts somewhere, (so I can make a portable power supply to use as a motherboard tester for quick onsite server diagnostics).

[vldmrrr]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Thank you mcnaryxc, of post #19. One of my dead power supplies also kicked into standby when I tried your same method.

Same here - I replaced this 22 uF and 47 uf right next to it (just because i extracted that first confusing it with 22 uF guided by the photo in post #19 - this white goo in the place is terrible, i also cut a thin wire from small transformer that happened to be buried into the goo). PS started right away. Before that it was making periodic tick sound like every second - probably with a relay, and there were no voltage on the out.

[Zak]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

Btw, here is the list of caps that you usually want to replace to fix these PSU's and their nominal values:
C907 - 100uF x 35V
C10 - 47uF x 50V
C909 - 22uF x 25V
C350 - 1uF x 50V (not 25V)
C901 - 100uF x 35V
C900 - 100uF x 25V
C903 - 47uF x 16V
C905 - 10uF x 25V
C353 - 100uF x 25V

Here is one correction to the voltage ratings that I came across; I'm doing my first recapping with one of these PSUs at the moment...

[Zak]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

I'm doing my first recapping with one of these PSUs at the moment...

Hmm. I replaced all the capacitors near the smaller transformer, but the unit stays dead.

[wasureppoi]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

[QUOTE=brianc;139322]I bought an xserve with a dead PSU thinking I could fix it.

Nothing is obviously burnt, it doesn't blow fuses, it has 0 volts output. The xserve manuals says it should have +12v on standby. According to the manuals there are 2 rails of +12v, and 3 IIC pins. No other voltage outputs.

Hi,
Would you be able to advise what the 3 IIC pins are?
Where or what do they connect to? Using an external atx with all the 12V cables my server will turn on and off with fans behaving normally but I cannot get any display.

[stj]

Re: Delta DPS-400GB-1A Troubleshoot (xserve)

the 3 i2c pins are a serial port to the microcontroller in the chipsocket.

if it plays dead you may want to resolder or change the crystal if nothing else works.