This isn't much of a work log, just pictures of significant stepping stones .

While most of the resistores and stuff are on the way, I have started putting together the 'control pannel', there isn't too much to see now, but progress will come! Id actually be a lot further down the road of I didn't cheap out- I need a really small square screw driver to attach the resistors to the heatsink

Anyways, here is what I have so far:



Forgive me for not adhering to standard coloring... two of the black binding posts are actually for the 5.5V and 3.3V rail, not ground, the other two are. The six reds are for the 12V. (measuring) The 24 holes underneath are for switches that are to be mounted.

edit: Oh to clarify, the metal sheet, is one of many from a shelf. Out with portability, this thing is going to be a piece of furniture as well.

Would you care to elaborate on the schematics for this (I would assume you drew them up before commencing building) and what functionality you are aiming for from it?

I'll be interested to see how this progresses.

See im not much of a planner, never drew any 'real schematics' only scribbles Functionality, its a load tester Itll be a bit more elaborate, and aesthetically pleasing than just a scrap of metal, but ill wait for the basics to take form first. This is going to be more of a process, up front, to do everything I want would cost too much, so this- I guess first version will just be the bare basics: an enormous load. Eventually, itll be a bit more elaborate such as a heat comparment to heat up units being tested, indiv amp meters for the rails and so on.

Ok

what will be your criteria for whether or not a PSU can support a given load?

are you going to look at transients/ripple?

Eventually, baby steps here! This part is going to cost around $500, so ittll be a little while before I can get a scope

Finished up the drilling, and got the proper screw driver to attach the resistors for the 5V load

looks good - i'm excited to see where this goes. that'd be the perfect way to review psus

I agree - much better than throwing it in a rig and going "yep, it works!"

Roadkill - what amperage are you looking at pulling from each rail? I would think 2 amp increments past something like 10 amps would be pretty good for load-testing.

This is a VERY cool project. You had mentioned this quite a while ago and I'm glad it's still "on the burner".

I'm interested to see if a proper load can "separate the men from the boys" so to speak. If not, it'll be time for one of those PC-based o-scope setups maybe Anyone have an idea of the cost of those these days?

Just about any oscilloscope is expensive.

Actually - integrating a standalone o-scope into that front panel to monitor voltages wouldn't be a bad idea. If you're really hammering on the PSU the DC conversion is bound to get pretty dirty.

Downfalls of several testing methods, plus some suggestions for DIY setups are discussed Here.
Any test set up, even one you build yourself requires some investment in equipment.

Currently, the setup they use over at HardOCP provides a pretty good guide to what is required to put a PSU through it's paces.
Their living document goes into a decent amount of detail and is a good starting point for anyone looking to put together something similar.

I got a 10MHz digital handheld scope for £80 (~$160)... I don't know if you'd class that as expensive for an oscilloscope, but I think it's fairly cheap...

You can get USB and PCI digital scopes for around the same price, with the added bonus of the inherent ability of data logging, something my handheld scope can't do (the next model up has an RS-232 serial interface)

Funnily enough, one of my DMMs has RS-232, but I'm not sure if the sampling rate is high enough to measure ripple/transients lol

Just working and doing what it is supposed to is entirely two different things...

That's what I meant by PC-based really. An analog probe/readout setup would be great for just personal evaluation, but for any sort of formal reviewing, I'd think logging would be an integral part. Once you've got the log data, it'd be easy to throw a ripple algorithm at it and get some presentable data.

For $150ish, I'd think that's really not that bad for what you could do with it in a reviewing environment.

Thanks for all the support guys! I would definitely like to see OCC build one too, im sure you guys would put something amazing together. I looked into building a transistor based load, but that went right over my head

USB O scopes are in the mid hundred range, perhaps the most popular one is the Stingray, quite a number of jonnyguru people use it, along with other sites

Right now, progress is halted for a bit, waiting for my US based contact to forward me a package... takes customs avoidance to a whole new level

edit: sorry I missed a few questions! As for load, I tried to cut back on costs by eliminating the number of resistors, so for example, the 12V rail, ill be using two different rating of resistors, allowing either increments of 144W or 48W. I do understand this undermines flexability, but its what I can afford to put into the project right now. My original plans called for about 30 50W 4R resistors, allowing for some incredibly small increments, but that would be too costly. Eventually, I do intend to add more resistors allowing finer tuning

That makes sense. A 48 watt (4 amp) jump isn't really that bad anyway.

yeah thats what I reasoned, the 4A might be a bigger problem with lower wattage units, not that I expect to come accross too many of those, but, if I do, thats where I will have a problem (points at seasonic)

Update time !

Besides whats already been mounted, I got a few more resistors today!


couldnt be bothered to edit this one

Those enormous mofos in the center are 150W ones =O

Thermal paste supplied by Arctic Silver

Hello all Now that school is done, I can finally get back to working on this thing Ive got all the parts in, minus screws and wires, so I began to play with layout.

One thing I noticed is, not too many test their PSUs under heated conditions. So one of my goals here is to make a heatbox. Im still debating material... something easy to work with, heat resistant and insulates, to some degree.

Heres a rough run down


(BIG PICTURE)

Probably not at all clear, so Ill try my best to clarify. The majority of it will be the heat assembly, its really a two part thing, bottom shelf being the heater, and the top shelf being the box, which is not built yet =P



Alright, so not shown is the bottom mounted fan which brings cool air from the ground up through the heatsinks and out the top and into the heatbox. (Ill have pots for the top fan, and an exhaust for the heatbox to control temps, along with a thermometer)

For cooling the resistors, I have panelled off the back and front side to make somewhat of an enclosed area. On either side will an enormous AC fan pushing air right onto the heatsinks.

So here is where I am working on

1) [bottom right picture] best place to mount the small heatsink to not disrupt airflow
2) suggestions for material for the heat box?

more updates to come tomorrow/ the day after that, im going to start drilling =)

BIG, BIG, BIG update



Resistors mounted, heatsinks mounted, along with crappy psu for cooling fans



Nother angle

Whats missing from this pcture are the fans. intake/ exhaust at either end of the heatsink column, intake at the bottom, towards the middle of the heatsinks, and an exuast at the top near the far right side.



Heres an idea of how the two pieces will fit. The empty space on the right houses a plexi box for enclosing the unit being tested, where it will recycle heat produced by the resistors in order to simulate a stressed testing environment.

The emtpy space to the bottom left are for amp meters (eventually).

I'll say! That's looking sweet man. Very professional looking .

yeah looks ace

=D thanks guys! I ordered a bunch of other things tonight, bunch of molex connectors, pins, fan grills, a duct + adaptors (for my heat box)... and Im going to waste a perfectly nice Silverstone SFF case



A big hole is going into this, and a duct!

To come: stingray usb scope, amp meters for each rail, and maybe some more resistors... im feeling 1kw isnt beefy enough!

roadkill

You can get 1kW with that set-up?

My set-up, although not as well made, can only do about 750W before heat becomes a real problem and the maximum I am running any resistor at is 70% of its rated power. I have had to get four extra 1R 150W, one for each 12V line, to take me upto approximately 1300-1400W total. Will probably get four more to take me up to 2kW and that should do for a while.

Can I ask what value the 150W resistors are and is it one per 12v line?

Cheers

Paul

Hey Paul, thanks for your input!

I haven't actually tested this thing yet, so the 1kw is entirly speculated, and theoretical. Heat will for sure be an issue, only I dont know how big of an issue till I hook it all up . How hot are your 150W resistors getting? The big ones I have are 150W 3R resistors.

I might heatsink up the other side of the resistors too I guess, ive got tons of room ! These are the heatsinks I am using, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...=tab%3DWatching.

edit: no new updates for a few weeks... waiting on some more parts

roadkill

These are the resistors I have had to use:



When on the 12V lines they dissipate 144W each, they get pretty hot and need fans to keep them from melting. They are rated at 1ohm 150W without the need for heatsinks but do need air cooling.

Got these on ebay too. Apparently ex-russian miltary and I think I got them from Bulgaria or somewhere similar. The quality is actually pretty good and they do the job nicely. They are wirewound ceramic coated so they should withstand the heat. Time will tell.

Your 150R resistors will only dissipate 48W each maximum on 12V. You appear to have five of these that will give 240W total. Have you not miscalculated somewhere or are you fitting more? Don't want to throw a spanner in the works, just trying to help.

Regards

Paul

OOPS typo! I meant 150W 1R ... sorry about that! They are Arcol HS1501R resistors. I will have air cooling, a 25 inch AC fan in the back of the sink, and 4 120mms at various spots.

Those... russian mil ones, holy! Where did you find the mount for those?

And btw, your not 'throwing a spanner', I really appreciate your help. Best I sort all the issues out now than find out later! =)

I have used cast iron pipe mounting brackets for the resistors, not quite the right diameter but they do the job.

Need any help at all just ask.

Regards

Paul

It was a shelf till I took a dremel to it, previous page for 'before' pics edit nope, here http://forums.overclockersclub.com/index.p...d=1558512&#

From 3d page

Small update, started doing the wiring.

Just a tip, get a cheap crimp, and your hand will cry about it






(pics reduced to clean up thread)

(btw, its not 3 resistors connected to molex)

moved to previous page

Biggest update 07/14/08






(how it all fits together)

Does it work?

Whats your maximum load?

How's the temperatures?

Am I jumping the gun here?

Found a supplier for PCI-E 6 and 8 pin connectors if you need them.

Need any help just ask.

Regards

Paul

is the 120-80 adapter so that you can run ducting out the window?

I havent really tested it with a real power supply yet (real being, a proper one) I did plug in my fan power supply, works of course, but didn't push it. So, I dont know how much of an issue heat will be yet. My massive snake nests of wires probably does not help .

For the 6 pin and 8 pin connectors, I found some at performancePCs, work nicely, cept the screwed up half my order and sent me some male 4 pin molex connectors.

Nrg, duct isnt for out the window, althoug that would be a good idea =). Duct goes from load tester to silverstone case, its to pump heat into the case where the power supply being tested will be mounted. A heatbox!

Nice , is this to test PSU for OCC also?

Nope, this one is mine Paul's tester is with OCC

Ok, this afternoon, a lilttle package for Corsair showed up for me =) Just some preliminary runs, but it gets to be my guinea pig. Im finding that the resistors dont load up as much as I hoped for, heat isnt too big of an issue, ive got 4x 120mm fans and a large AC fan, so so far, at most, things just get hot to the touch. Sorry I dont have temp measures right now, Ill try to do that in the morning. I loaded 900W on this thing (as per calculations) but I'm only hitting 737W. I guess thats what you were talking about paul! Time to get more resistors. I cant say I am disapointed though, actually Im still very happy with the unit. Now I just need to scale it for more poweerrr .

Pics of course! Thanks everyone who followed, and the input to this thread!

737W AC? Yeah, I'd say you need more resistors heh... my main rig almost uses that much power

It could go more.. this is 'just a' 750W unit

Don't forget this is AC power and after taking efficiency into consideration your power supply will only be pulling about 600W DC.

Yup, so I need more resistors, and an amp meter!

Paul, I went looking again for the ex- russian mil ones, http://cgi.ebay.com/1-ohm-150W-5-Wirewound...5QQcmdZViewItem

Im going order a few

Ordered 6 of em! Im going to have to build another shelf for those Running out of space here.

This is how the whole setup would look like, all connected. (add another shelf off to the side of the main tester)




(flash outa batteries)


Killawatt


Temp @ exhaust + v readings

They get very hot so get a good fan on them. Be very careful when connecting them up as the connection is basically just bare oxidised copper wire and they don't look like they will take much bending before they fall off?

I used metal pipe brackets to hold them, perhaps you can find something similar. Due to the fact that these are ceramic coated the diameter tends to vary slightly, you will need brackets that are in the region 1 1/8" - 1 1/4" diameter.

If you can find an ammeter with a 30A DC range I would recommend it. I have two meters that are 20A DC maximum and when I had to measure the currents on the Tuniq review, at 22A, I had to put two meters in parallel.

Good Luck

Paul