ratdude's homebrew PSU tester 2.0

[ratdude747]

revision 1 was a joke... i posted it somewhere... anyway, time for a good psu tester:



the overview. it connects to the ATX connector on a PSU. it has a switch to turn the PSU on and dip switches to send specific voltages to a multimeter.



the atx plug. yes, i know it is not 20+4, but i had no 20+4 atx plugs to play with (my only junk board with it was not wanting to desolder, i wonder if it was rohs). I glued a strap to the sides of the plug to make unplugging easier. i will move the glue points to allow the use of a 20+4 psu, as the strap mount gets in the way as it is now.



the power switch and the dipswitch pack. the dipswitches allow one to simply and easily send voltages to a multimeter by connecting the probes to the sawed off molex connector and settin the multimeter to 20 volts dc. the switch pinouts are:

1 12v+
2 5v+
3 3.3v+
4 3.3v sense (redundant, my error)
5 power good
6 5v standby
7 -12v
8 multimeter on/off

I already have plans for 3.0:

- swapping dipswitches for an 8 way switch of some kind (if i can get one, linear slide)
- removal of 3.3 sense, addition of -5v
- swapping probe ports for multimeter connections
- addition of a v+ probe, attached to switch position 8 (for using on other plugs on the psu in the event of multiple rails per voltage)

Possibly in 3.0:
- power on switch on same board as the 8 way switch and:
- some sort of casing for the switch set, with the atx plug possibly in the box as well.

any other suggestions for improvement or other comments?

[mockingbird]

Re: ratdude's homebrew PSU tester 2.0

Very nice. Where do you test with the multimeter, on the underside of the dibswitch board? On an unrelated note, do you know if it's possible to add a P4 connector (I believe it's called -12V or +12V) to an old Pentium 3 ATX power supply?

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

1. see the yellow and black wire coming out of the pcb? the plug on the end is for the multimeter probes.

2. pIII psu+ 12v adapter (they do exist)= bad idea. not enough power on the 12v... stick to units with p4 built in, they have the proper power distribution.

[c_hegge]

Re: ratdude's homebrew PSU tester 2.0

For revision 3, you should give it some loading capability.

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

thats a whole new product... that will be a more invested product. that was not in the plans because:

the goal is to be able to test a psu without risking a mobo. i also want ti to be semi-compact for repair house calls. a load-tester is not what i am steering it towards.

a load tester is more for enjoyment at seeing things go boom... generally one can tell if a psu is crap or not just by seeing the brand and pulling the cover to see the guts. my only use for one would be to show people why thier powmax ain't worth poo... and then they will be like "you a-hole! you killed my psu! you're a #@&$ing dumb@$$! you owe me a new one you mother#@&$er!"

[c_hegge]

Re: ratdude's homebrew PSU tester 2.0

Ture...

I just thought of it since I'm loving mine. I've already taken two PSUs out with it. The other one I tested (a "450W" Codegen) survived it

[Radio Fox]

Re: ratdude's homebrew PSU tester 2.0

I see that you intend to change the DIP switch. That's a good idea since, as well as being fiddly to operate, there is a chance that you could damage the PSU if you select more than 1 voltage to test at a time. An 8 way rotary switch would be my choice.

Dont forget that an unloaded voltage test will only weed out a definite failure (e.g. missing voltage). It wont tell you that it's definitely a good PSU.

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

well... knowing how many PSU's have been bad by a high 5vsb, i figured better this than a a fried board...

a load tester would be a separate project.

8 position slide switches are a PITA to find... mouser has the 8 position rotary switches (but they charge $5 a pop if all i order is one). ratshack has only six postion ones, and they are no good for a pcb mount. the mouser switch would be easy to mount to the pcb. i also will add a toggle switch for on/off. i will find a replacement probe kit for the rest of it.

[Agent24]

Re: ratdude's homebrew PSU tester 2.0

Not bad, but I prefer a simpler approach: I just insert a piece of wire connecting PS_ON and GND, and go from there.

5v SB doesn't even need a jumper wire, since it's on as soon as you plug the PSU in.

But ultimately you do need some kind of load...

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

ok... 3.0 has been built more or less.

i will have pics soon... it is missing switch knobs and so the switch positions are not labeled yet.

it has the following features:

-direct connection to multimeter
- switch settings for 5v, 12v, 3.3v, 5vsb, power good, -5v, and -12v
-external probe for other volt rails/connections
- all in a desktop unit (no exposed pcb or dangling power switch)

as for the loading idea, i have an idea for that. what i might make for it is modular loading units that are for different wattages and which could be connected to different plugs on the psu and could be linked together if needed. that way, if all you need to take is the tester, you can save the weight of the loading units, but you still can load things.

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

3.0.1 is out. dummy here wired the new ATX connector wrong... off goes the glue and it's resoldering time.

works fine now...

[Agent24]

Re: ratdude's homebrew PSU tester 2.0

Your post needs more photos!

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

here you go:

overview:


the front:

it has a switch to turn the psu on and off... and 2 6 position rotary switches.

switch 1:

1. 5v+
2. 12v+
3. 3.3+
4. switch 2
5. probe
6. off (ground)

switch 2:

1. 5vsb
2. power good
3. -5v
4. -12v
5. NC
6. NC

bonus points for figuring out what i cut to make the frame for this tester

the new atx plug, with the strap moved to allow 20+4 compatibility:


the back wiring:



once i get knobs, i will dremel cutter off the switch shafts to length and i will label the switch positions.

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

crap. it timed out and the pics are in the wrong order. please use common sense when viewing.

[Radio Fox]

Re: ratdude's homebrew PSU tester 2.0

Did you go with the Radio Shack switches in the end?

I notice that Radio Shack don't specify whether they are "make before break" (shorting), or "break before make" (non-shorting). Make sure that the rotary switches you have used are the non-shorting type.

[Pyr0Beast]

Re: ratdude's homebrew PSU tester 2.0

I'd use 1kOhm resistors before switches. That way it wouldn't matter.

[ratdude747]

Re: ratdude's homebrew PSU tester 2.0

i looked at the switches before i bought them, they are non-shorting.

i added knobs the night of the last pics, i forgot to take a pic, so here ya go:



(yes, my handwriting sucks)

It works great... the nice thing about me making it multimeter independent is that if I ever find a decent analog meter or a scope, it is an easy switch.

any more comments?

[Radio Fox]

Re: ratdude's homebrew PSU tester 2.0

...It works great... the nice thing about me making it multimeter independent is that if I ever find a decent analog meter or a scope, it is an easy switch.

any more comments?

To make it completely self-contained & more compact, how about including its own digital readout?

Digital multimeters are dirt cheap these days. You can get one for less than $5. You could rip the guts out & use the meter set to its 20V range for your readout. Your on/off switch is already double pole, so you could use the other pole as the switch for the multimeter supply as well.

You could fit sockets to the front panel for connecting any external equipment, such as a scope etc.

[Uranium-235]

Re: ratdude's homebrew PSU tester 2.0

you could just spend $20 on a really good psu tester with sata, 24 & 8 support

[tronxkid]

Re: ratdude's homebrew PSU tester 2.0

you could just spend $20 on a really good psu tester with sata, 24 & 8 support

Thats not all about getting some testing equipment buddy.

FUN + PLEASURE + PRIDE = DIY