IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

[tom66]

Okay, so another eBay bargain. Got two DPS-1200B's for £5.98, including shipping.

These give 98A on 12V each, as well as 5Vsb at 0.1A. Both are new in open box. They are rated only for 200 - 240V input, I guess because they would pull too much from a 115V input .

Who wants to see inside these?

Challenge here is to figure out how to turn them on... I'm probably going to have to hard-wire in a signal to the PWM controller, as I believe it has an MCU in it (appears to have some kind of SMBus interface from reading up on the 'net... and the number of pins on the control connector does not look trivial.)

Also they have no fans, so they will have to be externally cooled. I plan to use these near their rated power at times, so the cooling will have to be good. Probably two 120mm fans. They will be in parallel to give 196A at 12V. I also plan to see if I can mod them to 13.2-14V output, but 12V will still be okay for my application.

[tom66]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Turns out, they are actually quite easy to turn on. From top left, short pin 2,2 to bottom right pin to activate 12V output. 5Vco is always on. LED on back should light up indicating DC.

I tested a PSU and it will drive about 1m of 1.5mm cable (almost a dead short), with no complaints. The wire insulation melts almost immediately but the supply doesn't flinch.

I also found it would start up at a minimum of 180Vac, but once running would work down to 150Vac - but it was just cutting out (AC indicator went out, followed one second later by the DC output LED) so it might be possible to disable that and get a lower input range, with correspondingly reduced output current. (Secret plan to use it off high voltage DC, if the PFC likes it. HVDC from 265V to 350V.)

I've already disassembled both and determined production date to be around 2003, but they don't look used at all. No dust or dirt in them. The build quality is very good. Stay tuned for pictures.

[tom66]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

I mean "BladeCentre" PSUs.

Very nicely made.

Interesting how small the transformers are. It appears there are two transformers wired in series. It is a forward converter of some sort, possibly full bridge with ZVS/ZCS switching (there are a few polycaps near the transistors.) There are four main switching transistors, eight output diodes(!) all TO-247.

Interestingly, the PFC stage is comprised of an IGBT and a MOSFET in parallel. I'm guessing the MOSFET switches on first, which happens very fast as it has fast switching speeds, but its RDSon is quite high, so it has high conduction losses. Then, the IGBT switches on. The IGBT is shorted out by the MOSFET until its Vce(on) falls below that of the Vdrop across the FET - essentially eliminating the switching losses the IGBT would normally have - and gaining all the benefits of lower conduction losses (essentially fixed Vce(on) * Ice)) at high currents. Very nice!

Primary caps are 470uF 450V Chemicon KMH x 2. Output caps are 3300uF 16V Rubycon YXG x 6. That's nearly 20,000uF of capacitance! Disappointingly though, there are a few Taicon/Ltec dotted around, which I am not so sure about. They are in low stress parts like the 5Vsb which only supplies 0.1A, so I suppose they are okay, but for a server power supply? Come on, that's just being cheap.

No optocouplers. Main output is secondary side controlled. The standby appears to be bias winding controlled, but it's not clear. Gates of power devices are driven through some transformers it appears and there's a 15V regulator on the board presumably to power this stuff. The primary current is sensed with a current transformer, I would guess this is how it limits the output power.

The build quality is very good. Both are more or less identical.

[PeteS in CA]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

FR4 PCBs and lots of heavy metal ... coolness!

[b700029]

Re: IBM ThinkCentre Delta DPS-1200BB PSUs (98A on 12V!!)

Also they have no fans, so they will have to be externally cooled. I plan to use these near their rated power at times, so the cooling will have to be good. Probably two 120mm fans. They will be in parallel to give 196A at 12V. I also plan to see if I can mod them to 13.2-14V output, but 12V will still be okay for my application.

Because of the extremely high power density these are designed to receive very high cooling or they'll very shortly self-destruct. The typical setup of these in a server has a bank of ultra high speed (and noisy) fans pushing the air through them.

Apparently there's also a 2880W variant for some other BladeCentres.

http://i195.photobucket.com/albums/z...003/IBM022.jpg

236A @ 12.2V, more than enough for light arc welding

[tom66]

Re: IBM ThinkCentre Delta DPS-1200BB PSUs (98A on 12V!!)

Because of the extremely high power density these are designed to receive very high cooling or they'll very shortly self-destruct. The typical setup of these in a server has a bank of ultra high speed (and noisy) fans pushing the air through them.

Apparently there's also a 2880W variant for some other BladeCentres.

http://i195.photobucket.com/albums/z...003/IBM022.jpg

236A @ 12.2V, more than enough for light arc welding

Wow. I need to get me one of those!

There is a temperature sensor on the primary switching transistor heatsink which goes back to the main processor board (controls on/off, SMBus etc... has a PIC16C27 on it...) I hope this will cause it to throttle back if there is no cooling. I left it on for about 10 minutes with no load and after turning it off, that heatsink was very warm, so I guess that part gets the hottest. (PFC sink was cool, as were output diodes.)

[PeteS in CA]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

The typical setup of these in a server has a bank of ultra high speed (and noisy) fans pushing the air through them.

"Noisy" is a rather vague term - some of the fans used on stuff I work on scream, but at $1500 apiece (not a typo!), they're obviously rather exotic. Will two 110CFM 120mm x 38mm fans be adequate for tom's purposes?

[c_hegge]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

$1500 for a fan? I got some 250CFM Delta fans for only $25 each. Over twice the airflow, but a fraction of the price.

[kaboom]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Get a small AC powered squirrel-cage fan, something like what old microwaves used. They're just like furnace blowers, but much smaller!

I'd try and duct something like that up to the PS- you not only need airflow, but have to overcome a "little bit" of static pressure. You'd just have to play around with some aluminum flashing and/or tapered wooden pieces to transition from blower to power supply.

Either way, it's cheaper than $1500, especially if you can find one on fleabay.



-Paul

[coolmeta]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Hi,
tom66 can you take a picture or write me details of these parts and send me
becouse i tried to improve cooling and I shorted two coolers with other cooler and they have burned. Power supply doesn't start. I will try to fix it changing these burned parts.

[tom66]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

The PSUs are at home; I'm in Leeds. I won't be back for at least 4 weeks. Can't help you right now.

Those resistors look to be minimum load resistors going to ground. Have you tried starting PSU with load? I can't see them causing a problem with the PSU starting, unless the PSU requires such a minimum load.

Do you get AC and DC LEDs on rear?

[coolmeta]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Yes i have such leds but if i connect psu to 230v AC led doesn't light DC led too

[coolmeta]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Nope it didn't work. I've connected 12v 20w bulb and psu didn't start Both leds didn't light.

[tom66]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

Which two heatsinks did you short together? It sounds to me like you shorted a live heatsink to the cold side. Probably the microprocessor and other parts on it are damaged which would be very difficult to repair.

[coolmeta]

Re: IBM ThinkCentre Delta DPS-1200BB PSU's (98A on 12V!!)

I shorted
I haven't noticed any other burned particles.