Fun with fixing I-Micro power supplies

[everell]

Re: Fun with fixing I-Micro power supplies

That systems takes less than 100 watts so it seems this is really top class PSU lol

top class? I can think of words much more descriptive!

[Behemot]

Re: Fun with fixing I-Micro power supplies

That systems takes less than 100 watts so it seems this is really top class PSU lol

[everell]

Re: Fun with fixing I-Micro power supplies

At present, the power supply is attached to a Pentium 3 Biostar M6VLQ motherboard with onboard video, 512 meg of PC100 memory, PS2 keyboard, PS2 mouse, and 40 gig Maxtor ATA100 hard drive. I don't consider this to be a very heavy load! The voltage measurements were made using this motherboard and hard drive as the load.

The board that blew it up turns out was not Pentium 4. It is a pullout motherboard from a EMachine, a K7MNF-64 made by FIC. It has a Sempron socket 462 AMD K7 2 gig processor (SDA3000DUT4D) and 1.256 gig memory. I am using the onboard video. It also had PS2 keyboard, PS2 mouse, and hard drive attached. I tried using one of the other rebuilt IMicro power supplies on it.....worked OK for several hours. The IMicro that worked had a much larger switching transformer.

The EMachine board was a pullout with some bulging capacitors. I had already replaced capacitors and checked out with blue esr meter. I tried using several of my repaired power supplies on this motherboard, and all worked fine. With a good power supply this motherboard does fine.

I am beginning to think that the small switching transformer is the culprit. It looked like the same size transformer that was in the power supply Uniqu3 rebuilt (from pictures he posted). I would have thought it would be capable of handling the AMD K7 processor mother board. I guess that the motherboard needs more than a 400 watt IMicro power supply.........

[Pentium4]

Re: Fun with fixing I-Micro power supplies

Wow, it exploded just connecting it to a P4 board?! What else was it powering?

Some interesting measurements: with no hard drive attached, the 5V rail reads 5.12 volts and the 12V rail reads 12.58 volts. When I attach the hard drive, a 40 gig Maxtor ATA100, the 5V rail reads 5.01 volts and the 12V rail reads 12.48 volts. Seems to me to be a rather large voltage drop when adding only a hard drive.

What else did you have hooked up to it? Was this with the P3 board or just a paperclip? I think it's very normal for the 12V to read very high with low 12V load on half bridge units. Since they were usually designed with low end ultra fast diodes, the schottky seems to bring the "low load" voltage up very high. As we know, these designs like 5V. It seems like the extra 5V from the hdd "levelled" it out a little bit. I'm just guessing. I bet if it were to power a 12V heavy machine, the 12V would drop to something around ~12.3V

I think that trying the Pentium 4 motherboard would again farkle its tra-la-la, so I am reluctant to put a heavier load on this 400 watt power supply.

I don't blame you. Maybe try a different board? I'm not sure why it would power the P3 fine and not the P4 system. It looks beefy enough especially with the new silicon you put in it.

[everell]

Re: Fun with fixing I-Micro power supplies

Back to the story of the last I-Micro I fixed. I was ready to test, hooked it to a Pentium 3 mother board, and watched the fireworks. I repaired it (see previous posts). It ran the Pentium board fine, but after a few hours it quit. I decided to give it the "Uniqu3" modification. I removed the output diodes and installed a Shottky 3045 on the 3.3 volt rail, a Shottky 3045 on the 4 volt rail, and a MBR Shottky 20100 on the 12 volt rail. To improve the input side I installed a pair of C2625 switching transistors. Applied power using the Pentium 3 Biostar M6VLQ motherboard as a load. Ran it many hours with no trouble. At last it is fixed.....I thought.

With boldness, I attached it to a Pentium 4 class motherboard. Pushed PS_on switch.....BANG, fizz, and a small fireball! Both switching transistors shorted, the C945 driver transistors were bad, and the 7500 pwm chip was shorted. Also a couple of bad diodes, and the resistors in one of the switchers had blown resistors. I replaced the switching transistors with 13007. I also replaced the two electrolytic capacitors in the switching transistor circuits. Replaced the driver transformer just in case it shorted. Attached it to the Pentium 3 motherboard and once again it came to life.

Some interesting measurements: with no hard drive attached, the 5V rail reads 5.12 volts and the 12V rail reads 12.58 volts. When I attach the hard drive, a 40 gig Maxtor ATA100, the 5V rail reads 5.01 volts and the 12V rail reads 12.48 volts. Seems to me to be a rather large voltage drop when adding only a hard drive. I think that trying the Pentium 4 motherboard would again farkle its tra-la-la, so I am reluctant to put a heavier load on this 400 watt power supply.

So what do you think?

[Dan81]

Re: Fun with fixing I-Micro power supplies

Are you kidding? Of course it can. Didn't you check the label on the power supply case? It has UL and CE certification, along with certifiction from a couple of other certification agencies.

Am I the only one who thinks that UL logo is fake?

[stj]

Re: Fun with fixing I-Micro power supplies

that certifies the case, not the contents.

[everell]

Re: Fun with fixing I-Micro power supplies

Can it do labeled power now?

Are you kidding? Of course it can. Didn't you check the label on the power supply case? It has UL and CE certification, along with certifiction from a couple of other certification agencies.

[Dan81]

Re: Fun with fixing I-Micro power supplies

Can it do labeled power now?

I don't have a load tester so I don't know.

[Behemot]

Re: Fun with fixing I-Micro power supplies

Can it do labeled power now?

[Dan81]

Re: Fun with fixing I-Micro power supplies

Give us a picture of it so we can compare it with the first two I fixed in this thread. Together we can show the world what can be done with an IMicro power supply, even if it is a !@#$%^&*

I'll try doing so. Keep in mind that I don't have any dead FSP,Antecs or such to take parts from,so it may look quite bad.

[ben7]

Re: Fun with fixing I-Micro power supplies

Give us a picture of it so we can compare it with the first two I fixed in this thread. Together we can show the world what can be done with an IMicro power supply, even if it is a !@#$%^&*

Oh 'deer' xD

[everell]

Re: Fun with fixing I-Micro power supplies

Give us a picture of it so we can compare it with the first two I fixed in this thread. Together we can show the world what can be done with an IMicro power supply, even if it is a !@#$%^&*

[Dan81]

Re: Fun with fixing I-Micro power supplies

So did you fix the 450W IMicro and get it working?

I was just given a Okia-500ATX rated for 500 watts. And I thought the IMicro power supplies were bad. This Okia has a smaller than usual case size, is light weight, and has wimpy parts throughout. Four small diodes feeding a pair of Ricon 330 uF/200 volt main capacitors. Also the fan is stuck on this one. And this power supply is going to handle 500 watts????

Yes,I did get it to work. Now it's complete with PI coils,X cap and common mode choke. Also,replaced the old fan it had with a Titan fan (Delta built).

[everell]

Re: Fun with fixing I-Micro power supplies

I didn't fix the 400W one I had in my parts pile. It wasn't worth it with the wimpy heatsinks it had. The 450W rated one has better heatsinks,so it was worth fixing.

So did you fix the 450W IMicro and get it working?

I was just given a Okia-500ATX rated for 500 watts. And I thought the IMicro power supplies were bad. This Okia has a smaller than usual case size, is light weight, and has wimpy parts throughout. Four small diodes feeding a pair of Ricon 330 uF/200 volt main capacitors. Also the fan is stuck on this one. And this power supply is going to handle 500 watts????

[Dan81]

Re: Fun with fixing I-Micro power supplies

WHAT??? You didn't fix the I-Micro??? That was the fun part of this entire thread!

I didn't fix the 400W one I had in my parts pile. It wasn't worth it with the wimpy heatsinks it had. The 450W rated one has better heatsinks,so it was worth fixing.

[everell]

Re: Fun with fixing I-Micro power supplies

..... at that point. I got a fuse from another iMicro board I discarded.....

WHAT??? You didn't fix the I-Micro??? That was the fun part of this entire thread!

[Dan81]

Re: Fun with fixing I-Micro power supplies

haha ok xD

Good to hear that you got it working. :P

Yeah. After fixing it,I was reluctant to turn it on first because I thought it would go but it was okay at that point. I got a fuse from another iMicro board I discarded,and the wire choke and PI coils came from a Deer (it's a choke,nothing can harm from a Deer,and shock,that Deer had PI coils)

iMicro seems to be around here rebranded as Delux,but not that often - Delux uses either Sun Pro or iMicros for their 400W models,and easy to spot also:

iMicro/YX-GP built 400/450W Delux units have a rocker switch on the back.
Sun Pro 400W Delux units don't.

BTW,I've noticed Sun Pro built 400W Delux units are better than Raidmax - this makes me think Raidmax is worse than anything. I've seen Sumvision and Delux units being way better than Raidmax units,with the AT2005B (not 2005 from DEER) being one of the good platforms of Sun Pro. At least that one had PI coils unlike Raidmax.

Fun fact: When I tried to remove the cracked fuse,it broke in half!

[ben7]

Re: Fun with fixing I-Micro power supplies

Don't worry about the ferrite anymore since just the fuse blew,not a biggie for me. Replaced it,placed the choke in the correct position and now it works fine.

haha ok xD

Good to hear that you got it working. :P

[Dan81]

Re: Fun with fixing I-Micro power supplies

Fault currents CAN be hundreds or even thousands of amps ... they WILL blow out PCB tracks as well, fairly often. :P

Don't worry about the ferrite anymore since just the fuse blew,not a biggie for me. Replaced it,placed the choke in the correct position and now it works fine.