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Re: Server converted power supplys.

Posted: 15 Mar 2018, 22:26
by sureshot
This is only a small offering, literally. I had to give it a few days of use to see if it behaved reasonably. As most come here looking for "BIG POWER" this might not be for everyone. Although it does cover a multitude of sealed smps units.

The one below was surplus from some old thin clients I had. I started by measuring the voltage whilst the unit was intact. Then the case was split by scoring round the case edges multiple times with a sharp stanley knife. On opening it up I had a quick scoot around the pcb, make sure all capacitors looked ok.

As the wires to the lead had age hardened I decided to replace them with twisted pairs, total wire capacity could carry 8 Amps. As this is a 12 Volt 4.16 Amp power supply, I thought that adiquate. There is no space for terminal or binding posts in this, so I had a rethink and used good quality speaker terminal plate with spring back terminals. I've seen these on retail units stating up to 5 Amps current. If you get good quality ones you could go to 10 - 12 Amps easily with these terminal plates.

Mounting the terminal plate was easy, but I did use nylon machine screws, there are two internal heatsinks, whilst they might be at a low potential I was not taking that for granted. ( in times gone by I've come across heatsinks in atx units that where at mains potential) Put a piece of card glued over the soldered terminal. A test whilst the unit was in two halves, all looked good so it was reassembled. Standard araldite epoxy worked great, allowing over night drying. Tape or a small clamp does the job nicely.

As I don't have a scope at the moment, it's a case of taste it and see. No problems powering an 80 channel cb and an old tagra 25 watt linear amplifier.
Some overs later and all seems fine, current drain was just over 3.2 Amps with that load combination, voltage drop 0.2 Volts under load. So it won't win any prizes in terms of power, but for what it is I'm pleased with it. This process could be adopted to many sealed smps type units, this is what I had laying around.

I'm tempted to look for an oscilloscope, but eBay has only junk, I've got my eyes on a 40mhz hand held unit, might invest in one. It would be interesting to see ripple noise for a known load current, with any smps. Next offing will be back to big server units. Hope some can see potential in this modest offering. :)

Re: Server converted power supplys.

Posted: 16 Mar 2018, 12:17
by kilimax
Some interesting posts Sureshot. :thumbup:
I have 2 large boxes stuffed full of power supplies of various types, most are rated at 12 volts, a few are somewhere between 5 & 9 volts.

While I don't see me having the need for something like this, I may look out some of the larger 12 volt bricks and see what they're like.

Re: Server converted power supplys.

Posted: 16 Mar 2018, 12:21
by MrWeetabix
Cracking little project.... be nice to re-purpose some older PSUs. That one from the thin-clients would be ideal for someone who was travelling. Much easier to pack than a 3/5 standard CB PSU or similar


Re: Server converted power supplys.

Posted: 16 Mar 2018, 13:16
by sureshot
Thanks for the comments guys, yes there are lots of sealed psu units that could be viable for use. Couple of pictures for size scale. The 3 - 5 Amp is a standby power supply. But as for the little hp smps, you could put it in your pocket its that small.
If your needs are modest, this type of psu might do you fine. :)

Re: Server converted power supplys.

Posted: 12 May 2018, 22:00
by sureshot
Give this a mention, but only the one image.
Bet somewhere in the country, world for that matter. Is currently pulling there hair out with a noisy power supply fan. This is for the Xbox 360 power supply grey brick 175 watt version (different technique for the other two models of grey brick psu ) I've not attempted them yet, as heatsink runs the length of the unit in the 203 watt psu.
This one's fan was sounding like a cement mixer, quick explanation.
Unpowered ! Remove the lid after taking out the four selftaping screws. Snip the fan lead as close to the old fan lead as possible. Find a 40mm axial fan with as low as a power rating as you can, I suggest sunnon fans.
Next remove all the plastic ducting in the top half of the case from the inside, including the old fan.

You will see a rectangular recess in the case rear where the old fan was located. Centre that recess drilling a pilot hole, use a 38mm wood spade flat bit. It must be sharp, drill slow half through one side so you break the surface with the 38mm bit. Now come in from the other side until your through the case. Slow and steady so as not to crack the case. Expect noise and mess :D
Now line up your fan drilling 4 x 3.2mm holes for the new fan and guard. 20mm M3 machine screws work well with washers and nuts. Once fitted dry fit the case lid, making sure no screws touch any internal metal parts, heatsink etc. That bit is very important to check.
Now strip back enough of the internal fan lead and bare the two wires, + - Shorten your fans flying leads, so you've got enough to solder both leads. Push heatshrink tube on before solder leads.
Solder the leads, shrink the tube over the spliced leads. Route the cable such that nothing is fouled, and is neatly tucked away from the fan blades. Use hot glue if you like. Refit the case halves and power on to test. Quiet fan years more service happy days.

At some point I will tackle the 12 Amp and 16 Amp grey psu bricks, as there fans are just as likely to be worn out over the years. :)
This modification is for the 175 Watt 14Amp unit.