Upgrade a 300watt noname power supply

[bauto601]

Hello,
I have a generic 300watt power supply. The type of the power supply is: Model: ATX-300.

Here are some pictures of the power supply:

The overview of the power supply. It looks better than a lc 300watt psu.


The secondary side of this power supply:


And some information of the psu:

STPS2045CT


STPS1545CT


BYQ28E


The filtering stage and the 2 big capacitors:


I think the diodes are 4Amps and the big capacitors are 470UF 200V

How can i upgrade this power supply? I want to upgrade it because i want to learn something about power supply's and i like to solder. I was thinking to upgrade the rectifiers at the secondary part of this power supply, but what do you think guys?

[Sorry for my bad english, i am 13 years old and dutch, but i am learning it!]

[c_hegge]

Re: Upgrade a 300watt noname power supply

Your English is not bad at all, actually.

Yes, I'd make sure the rectifiers are all rated for at least 30A. Also, it looks like that PSU used fuhjyyu capacitors. Replace them with Japanese counterparts. It looks like there's ample room for larger capacitors too, so beef the ones after all of the coils up to 2200 or 3300uF.

The OEM for this PSU is Channel Well (CWT).

EDIT: You could also improve the primary side. Replace the diodes (those are 3A, not 4) with a 6A rectifier, and the primary caps with 680uF or better.

[bauto601]

Re: Upgrade a 300watt noname power supply

Nice to hear that my english is not so bad at all! So larger primary caps, bigger rectifiers at the secondary, bigger caps at the secondary and replace the diodes for a 6A rectifier. And how much can the power supply deliver after changing all the components?

[goodpsusearch]

Re: Upgrade a 300watt noname power supply

Nice to hear that my english is not so bad at all! So larger primary caps, bigger rectifiers at the secondary, bigger caps at the secondary and replace the diodes for a 6A rectifier. And how much can the power supply deliver after changing all the components?

What switching transistors does the psu have?

[bauto601]

Re: Upgrade a 300watt noname power supply

What switching transistors does the psu have?

Do you mean the components on the primary heatsink?

[goodpsusearch]

Re: Upgrade a 300watt noname power supply

Do you mean the components on the primary heatsink?

Yes.

[bauto601]

Re: Upgrade a 300watt noname power supply

Yes.

I'm not at home at the moment, tomorrow i wil post the specifications of them.

[pdavid]

Re: Upgrade a 300watt noname power supply

Had like two dozen of these CWT psus at work and even after six years (24/7) they sort of worked. Standby gets a little cooked and sometimes the primary capacitors (Koshin) start to bulge.
If you can do as others suggested and put an even bigger transformer, (like ERL35) 13009 primary transistors and 680uF capacitors plus recap and upgrade the secondary I think this psu would be a good emergency spare. I hope this helps.
Also here is one of the lowest-of-the-low versions of this psu claming 300W but exploding at 200W.

[bauto601]

Re: Upgrade a 300watt noname power supply

Here are they:

[c_hegge]

Re: Upgrade a 300watt noname power supply

13007s. I can never pull more than about 250W from them without blowing them up. I'd replace them with 13009s, D209Ls, or 2SC3307s

[Pentium4]

Re: Upgrade a 300watt noname power supply

If you're going to upgrade to 30A rectifiers then you need a better heatsink for the secondary. You don't HAVE to use japanese caps on the input but it doesn't hurt, and I'd use 680uF caps instead of 470. I would add a bridge 6A rectifier to replace the diodes. They look decent but their ratings go down a lot when they get hot. I'm guessing that thing has probably 1 or 2 caps for 12V filtering so definitely increase the capacitance on those caps, at least 2200uF, preferably 3300uF. Replace those orange ceramic discs on the primary with matching Y caps, and if you're up to it solder an X cap to the AC receptacle. The transformer looks good enough...Also, I would replace the fan with a high quality ball bearing fan
Edit: didn't realize hegge mentioned some of the same things

[bauto601]

Re: Upgrade a 300watt noname power supply

Hello, here i am again
Thanks for the tips P4! I am going to replacing the secondary rectifiers tomorrow. You say that i need a bigger heatsink on the secondary, i can do this but i can also add a second fan that blows right on the heatsinks like here:
http://laptopshopcyprus.com/41-247-l...aptop-shop.jpg

Another question: I am going to replace the 3,3/5v rectifiers for bigger one's that are skottky. But at the 12v there are only holes in the pcb for a small rectifier. So i am going to replace the 12v rectifier to another stronger rectifier that is also a small one but that one is not skottky. Tomorrow i will post pictures and specs of the new rectifiers.

[goodpsusearch]

Re: Upgrade a 300watt noname power supply

13007s. I can never pull more than about 250W from them without blowing them up. I'd replace them with 13009s, D209Ls, or 2SC3307s

+1

250W max

300W peak for couple of seconds maybe

[Pentium4]

Re: Upgrade a 300watt noname power supply

Hello, here i am again
Thanks for the tips P4! I am going to replacing the secondary rectifiers tomorrow. You say that i need a bigger heatsink on the secondary, i can do this but i can also add a second fan that blows right on the heatsinks like here:
http://laptopshopcyprus.com/41-247-l...aptop-shop.jpg

Another question: I am going to replace the 3,3/5v rectifiers for bigger one's that are skottky. But at the 12v there are only holes in the pcb for a small rectifier. So i am going to replace the 12v rectifier to another stronger rectifier that is also a small one but that one is not skottky. Tomorrow i will post pictures and specs of the new rectifiers.

That extra fan would help a lot! Especially if it's always getting 12V. Yeah that's typical of an older design. A 20A schottky for 12V would still be a good improvement. And yeah there's nothing wrong with your english, it's better than a lot of native speakers in my area

[TELVM]

Re: Upgrade a 300watt noname power supply

... i can also add a second fan that blows right on the heatsinks like here:
http://laptopshopcyprus.com/41-247-l...aptop-shop.jpg

I'd put the second fan this way:

Straighter flow and less turbulence = better cooling.

[c_hegge]

Re: Upgrade a 300watt noname power supply

That's how I'd do it on this PSU. With the shape of the heat sinks, they will work better with front to back airflow, not 90 degree top to back.

EDIT: I went on a similar venture to this with a Rexpower PL-400 power supply. You mey find that thread interesting - https://www.badcaps.net/forum/showthread.php?t=11247

[Logistics]

Re: Upgrade a 300watt noname power supply

OP's PSU looks almost exactly like an Antec PSU I recapped in the past; either a PP-303X or an SL-350. Can't remember which one, but it looks SO familiar.

[bauto601]

Re: Upgrade a 300watt noname power supply

Here a pictures of the power supply now:


All the parts i use in this power supply come from other (broken) power supply's. So i found this heatsink on a old broken power supply:

The red line on the big heatsink is the line that i am going to follow if i am sawing the heatsink in the right shape (is that good english )
I am going to place a fan at the front of the power supply and at the back of the power supply.

Here a picture of the new (ehhh.. from a old psu) rectifiers:


I can't find anything of the 1st rectifier.




Are these rectifiers good ones? And how can i replace the diodes with a rectifier? I also hear that i have to replace almost whole the power supply so this is going to be a job for the whole week

[c_hegge]

Re: Upgrade a 300watt noname power supply

Those rectifiers are fine. Use the BYV42E on the 12V rail, the MBR4045 on the 5V rail and the SBL4040 on the 3.3V Rail. Sometimes, if you unsolder the 4 diodes, the PCB will be screened for a rectifier as well. Do that and post a shot of what's under there.

Your new heat sink looks nice and chunky, although you may have to drill a couple of extra screw holes for the rectifiers. I'd install it with the overhang over the toroid coils and caps, not over the transformer. The other consideration is that you don't want the primary heat sink to be much smaller than the secondary one if the fans will have a speed controller, because the secondary heat sink (which controls the fans) could stay cool, while the primary heat sink is red hot, and the fans won't speed up.

[bauto601]

Re: Upgrade a 300watt noname power supply

Those rectifiers are fine. Use the BYV42E on the 12V rail, the MBR4045 on the 5V rail and the SBL4040 on the 3.3V Rail. Sometimes, if you unsolder the 4 diodes, the PCB will be screened for a rectifier as well. Do that and post a shot of what's under there.

Your new heat sink looks nice and chunky, although you may have to drill a couple of extra screw holes for the rectifiers. I'd install it with the overhang over the toroid coils and caps, not over the transformer. The other consideration is that you don't want the primary heat sink to be much smaller than the secondary one if the fans will have a speed controller, because the secondary heat sink (which controls the fans) could stay cool, while the primary heat sink is red hot, and the fans won't speed up.

To begin:
I don't know which rectifier is what so i don't know which is the the 3,3, 5 and 12v rectifier. Can you tell me which rectifier is what? The big heatsink is made of too thick material so it wil short some components on the pcb.. But from another psu i have these heatsinks:

Are these big enough?

Also, this psu has no fan control so it is making terrible noise when it's on. After replacing the rectifiers i am going to test the unit and a.fter the testing i am going to unsolder the diodes.