Re: Found a brand new Comp USA PSU
Its more obvious on the designs where they use a transistor to generate the 3.3v rail from the 5v rail.
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Re: Found a brand new Comp USA PSU
Wow, that's pretty lousy. But I guess tons of manufacturers do the same type of thing when they just beef up the 12V on old half bridge ATX 1.3 designsLeave a comment:
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Re: Found a brand new Comp USA PSU
Yes, This design looks particularly old. The 5vsb transistor not being attached to the heatsink is a good indicator that this was originally an AT design that was adapted to ATX.Leave a comment:
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Re: Found a brand new Comp USA PSU
So it's pretty safe to say that if a PSU is using a 2 transistor circuit then it is a very old PCB design?Leave a comment:
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Re: Found a brand new Comp USA PSU
5VSB transistor usually dissipates no more than 1W with 5V, 3A load. Two-transistor 5VSB is actually pretty efficient, around 75% to 80% (which is good for a small, low cost flyback.) And it's possible to make it without the killer cap, but you may as well use a controller IC because all of the tweaks will likely cost more than a cheap TNY-type switcher.Leave a comment:
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Re: Found a brand new Comp USA PSU
What ripple would it have with such output?
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Re: Found a brand new Comp USA PSU
I don't think it can do 300W. I'm just guessing man
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Re: Found a brand new Comp USA PSU
True, but with only an ultra fast on the 12V it may hit the 70's with a 5V based system.Leave a comment:
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Re: Found a brand new Comp USA PSU
Such things with ultrafast(s) usually don't go over 70 %, it's somewhere between 60-70 % usually.Leave a comment:
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Re: Found a brand new Comp USA PSU
You think the efficiency would be that low? lolLeave a comment:
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Re: Found a brand new Comp USA PSU
I don't think 3 A primary diodes would be enough for 60% efficiency at 300 W and 115 V AC. Just that nobody mentioned that…Leave a comment:
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Re: Found a brand new Comp USA PSU
Lots of info in that thread, awesome.
Wow, no choke or inductor for the 3.3V? That is embarrassing. I think it's safe to say that even JEE is a step above Rulycon, how long did it take for them to bulge? It also looks like they sliced off the top of your heatsinks, I wonder why.
Only 1A out of that transformer? Ouch! The 250W and 300W look to use the same size one too
Nice mod btw... I agree Bestec are much much better. I love working on them but the glue drives me insane sometimes
Last edited by Pentium4; 07-08-2013, 07:33 PM.Leave a comment:
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Re: Found a brand new Comp USA PSU
I still have my CompUSA 250 watt power supply
https://www.badcaps.net/forum/showthread.php?t=8337
Mine had all Rulycon capacitors, nearly all bloated. As somewhat of a joke I replaced all of them with Fujiyu pullouts from old Antecs. Far as I know, none of the Fujiyu caps have failed yet and the psu still works. I removed the two transistor 5vsb circuit and installed a DM311 mod. However.............the 5vsb transformer is so small it gets VERY hot when load testing. Might be good for one amp, but not much more! I have never found another 5vsb transformer with a similar pinout.
I am somewhat jealous when an old CompUSA Leadman can get so many responses and such loving attention.....They are such terrible crap. HiPro and Bestec are so much better.Leave a comment:
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Re: Found a brand new Comp USA PSU
You know it's sad when even the average Deer is better than a Leadman (Although not the one I'm about to post in the gutless hall of shame!)Leave a comment:
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Re: Found a brand new Comp USA PSU
have not seen a leadman unit worthy of anything but use as a rifle target.
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Re: Found a brand new Comp USA PSU
TO-247 and TO-3P also have better thermal resistance from junction to case, and can accommodate a larger die. Price-wise, TO-220 is cheaper.Leave a comment:
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So I have a cheap non working ATX PSU that I was learning to repair a decade ago. At the time, it blew the main fuse, bridger rectifier, NTC, and primary 9A 900V MOSFET. Replaced all except the MOSFET. 5VSB came back online. Then I poked around in it so much, measuring components one by one to a point I accidentally made the 5VSB circuit primary side went bang. Blown the AP8022 (Viper22A) PWM chip, along with a low resistance resistor and the PC817 opto isolator. I replaced them all.
In the process of poking around, I also lost a zener diode that stabilize the voltage coming from... -
Hi,
Finally replaced all of the shorted 4148's and resistors and an blown tl431 on my FSP300-60GTF after 5VSB going crazy and destroying it self. Those components also made the secondary transistors appear shorted (while in reality they weren't).
Powered it on through my dim bulb tester and they (bulbs) only flash once meaning primary caps are getting charged, but that's it. No 5VSB, PS_ON voltages.
I am sure I have replaced the components correctly and that there weren't any shorted/blown traces left.
Any ideas where to go next? -
Hello...
I got my self a dead CM V700 PSU, with nothing on +5vsb
I have tried to fix it for the past 2 week, and I'm stuck... so i guess i post it here to get some pointer before i scrap it..
As you can see in photo, the psu still pretty clean, no visible damage or bulging cap.. when i got it, it still has CM seal on it
The +5vsb system use ICE2QR4765, I have trace and measure the voltage on ICE2QR4765 and the only voltage reading i got is in VCC 4.8v, Drain 310v and FB 3v.
I have read the datasheet and and still can not... -
Rescued this one
Started it up in the computer case, and noticed that it would shut down after about 10s in the BIOS
Took it out, connected to hard drive and it loses all power on all rails (except for 5VSB) after about 40s or so. (the same result happens without a hard drive connected)
The 5VSB drops to 2.5V when it 'shuts down'
And the voltage across the primary cap falls from 335V to 330V at the same moment
I think that the 5VSB is regulated by an A6069H PWM chip (which was initially dropping to 2.5V even before the the PS-ON was grounded - but it now stays at... -
Hey there guys. I've got a Corsair power supply that's come across my bench dead. I usually don't mess with power supplies, but it's a slow week so I'm giving it a whirl.
Taking it apart I heard a screw rattling around inside, and when I got it apart I found a couple blown components near what I think is the 5VSB area.
There's a 22ohm resistor that's melted and open, but it still has the bands.
The other part is a zener diode and it's top went to jesus, so I can't read the marking.
It looks like the diode connects the source and drain of a TNY284...
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