Rebuilding Rosewill 350W

[370forlife]

So I've had this rosewill 350W psu for quite some time now. It is of L&C origin. Not too badly built compared to other gutless wonders that were free with a $25 case. YC caps everywhere. Large sized main caps, 470uf, 200V each. input filter consists of the smallest y caps I have ever seen, along with a coil. standard 4 diode treatment.

I have NOT bought any of the parts used to rebuild this. They are all scavenged from 2 bestecs. One a bestec ATX-200, they other a ATX-250-12Z.

My handy work so far:

Replaced input YC caps with Panasonic 470uf, 200V caps. Replace red round X cap with actual X cap, put X cap in place where no X cap was. Replace tiny Y caps with larger, nicer Y caps. Install bridge rectifier (GBU606 6A @ 100C), replace smaller caps from YC to all CEC international holdings (Enermax uses these in almost all their new units), 5vsb cap 50v, 47uf to 50v 220uf Capxon (all I have right now). Have not touched the secondary caps yet. Jumpered it before with a quantum 10.2gb hard drive attached for a load.

I also added a plastic sheet that goes under the pcb to reduce the risk of shorting on the case. This was pulled from the bestec atx-250-12Z.

Before:

12V: 11.69-11.89, sparatic, constantly changing.
5v: 4.66-5.05, sparatic, constantly changing.
3.3v: 3.03V-3.14v, sparatic, constantly changing.
5vsb: 5.65v solid.

After (have not touched the secondary caps yet!)

12V: starts at 11.92, settles at 12.01
5v: starts at 4.99, settles at 5.02
3.3v: starts at 3.22, settles at 3.35
5vsb: solid 4.22 (not sure how that happened, but its not frying the chipset!)

Amazing what just a input filter will do. Now time for some secondary caps and see where those voltages will start off then.

Before pics:





After pics:

[momaka]

Re: Rebuilding Rosewill 350W

You should have fixed the Bestec ATX-250 12Z instead as that one probably wasn't a motherboard killer.
----
Also, 5.65v on 5vsb? That's out of spec by over 10%!! Good thing you caught it.
At least the Panasonic caps stabilized the voltages. Those YC primaries probably have 0uF left .

5vsb: solid 4.22 (not sure how that happened, but its not frying the chipset!)

... Probably the 50v, 220uF CapXon. That voltage is also more than 10% out of spec by the way. But I guess it's better than 5.65v, though.
On the random side of things, that main transformer has a fake "35" rating. Should say 33.

[ratdude747]

Re: Rebuilding Rosewill 350W

i still see some ugly jumper wire that could go. look between the x cap and the bridge. i think a component could go there...

also, do yourself a favor and replace the 115/230 switch with some insulated jumper wire. that way nobody sets it to 230v. whats worse is when it should be set to 230 but is instead set to 115... search youtube for that and you will see some spectacular burn-ups.

[Krankshaft]

Re: Rebuilding Rosewill 350W

Another forum member PCbonez I think disabled these switches on school PSUs because students on 230V kept blowing them up.

He rigged them with a buzzer when the switch was set to 115V so they'd get busted even though the PSUs wouldn't blow anymore .

All the switch does is sends the input voltage to a voltage doubler on 115V and bypasses it for 220V.

[ratdude747]

Re: Rebuilding Rosewill 350W

now if he only rigged it with a smoke bomb...

[370forlife]

Re: Rebuilding Rosewill 350W

Both bestecs were defunct.

The 200W was actually rusting. It was sitting in a basement in a old compaq for years and it blew out one of the primary switcher's.

The ATX-250-12Z in not a mobo killer, but it was also bad. Could not figure out what was wrong with it. Everything looked fine. It was also a freebee from a customer's computer. I had no use for it and gave me some good experience taking parts out and putting parts in this.

Now...I have some good secondary caps I can scavenge out of a old, old 200W astec psu. All nichicon and UCC. BUT...this is a nice psu. Sure it is only 200W, but it is really nicely made. Should I gut it for caps, or should I gut this 200W newton psu from a dimension xps T500 with all rubycon caps?

The Astec has extremely short wires as it is from a compact hp.

I also have a really nice input filter that would go in place of the one already there, but I don't know how it would go, as there is 8 holes there. Would I just solder it in to the same 4 holes the filter that is in there is currently in? and what is the correct orientation?

[Newbie2]

Re: Rebuilding Rosewill 350W

If you ever purchase replacement parts I'm thinking that you should get a good 50V cap of 22uf or 47uf to replace your current 220uf CapXon cap. 5.65V before is too high, but 4.22V is in my opinion low.

Replace the YC capacitors on the secondary side with good new capacitors (increase the capacitance of the 12V cap if you want) and that power supply will be a respectable 250W power supply I'd say.

[Krankshaft]

Re: Rebuilding Rosewill 350W

now if he only rigged it with a smoke bomb...

I'd use a blue dye packet like in the bank bags .

[370forlife]

Re: Rebuilding Rosewill 350W

So do you guys think I should gut the 200W newton or 200W astec?

Also with the new input coil, should I just solder in in to the same 4 holes as the current one? Also, would there be any more of a improvement with it?

[everell]

Re: Rebuilding Rosewill 350W

With all the excitement of improving L&C power supplies, I too have been busy at work on my Raptor L&C 400 watt psu. In looking at your pictures, I see that the three transformers in your psu are identical to the ones in my psu.

I was not at all impressed with the two transistor 5vsb circuit. So I have begun the conversion process. The transistor circuit parts have been removed, and I have put together the add on pc board DM311 circuit. Here are two pictures of the added board screwed to the heat sink where the old 5vsb switching transistor used to be. It will be a few more days before it is installed and working properly.

Also, take a look at the physical size of the main switching transformer (ERL-35-2005) and compare it with the size of the main switching transformer in the Bestec ATX-250 12Z. The larger transformer in the Bestec will probably handle more power. I am convinced that the L&C will be doing good to hold a solid 200 watts.

The pwm and supervisory chip in our power supplies is the "chip of the year" 2005. I have never found a data sheet for it, but there is a schematic in Newbie2 post. It may be helpful to you.

[Newbie2]

Re: Rebuilding Rosewill 350W

With all the excitement of improving L&C power supplies, I too have been busy at work on my Raptor L&C 400 watt psu. In looking at your pictures, I see that the three transformers in your psu are identical to the ones in my psu.

I was not at all impressed with the two transistor 5vsb circuit. So I have begun the conversion process. The transistor circuit parts have been removed, and I have put together the add on pc board DM311 circuit. Here are two pictures of the added board screwed to the heat sink where the old 5vsb switching transistor used to be. It will be a few more days before it is installed and working properly.

Also, take a look at the physical size of the main switching transformer (ERL-35-2005) and compare it with the size of the main switching transformer in the Bestec ATX-250 12Z. The larger transformer in the Bestec will probably handle more power. I am convinced that the L&C will be doing good to hold a solid 200 watts.

The pwm and supervisory chip in our power supplies is the "chip of the year" 2005. I have never found a data sheet for it, but there is a schematic in Newbie2 post. It may be helpful to you.

Great work everell, it's good thing that you can design a more reliable +5VSB circuit. From what I see so far the original +5VSB circuit that L&C has is dependant on the capacitor in the C8 spot on the PCB.

Maybe we should all e-mail pictures and details of our improved L&C power supplies to Deer (the only e-mail address I could find was for Solytech's sales department, which is one of Deer's brands sales-dept@soly-tech.com)

[Newbie2]

Re: Rebuilding Rosewill 350W

Also with the new input coil, should I just solder in in to the same 4 holes as the current one? Also, would there be any more of a improvement with it?

Yes, that's what I did with my L&C power supply.

I don't know if there will be any improvement, probably momaka will know.

[ratdude747]

Re: Rebuilding Rosewill 350W

dont gut either one. good supplies are hard to find. get fresh caps to be safe.

[Newbie2]

Re: Rebuilding Rosewill 350W

good supplies are hard to find.

In my opinion I don't think that's true, one can easily be ordered off Newegg or TigerDirect, and you can walk into a local computer shop and chances are they will have some high-end quality power supplies in stock.

[momaka]

Re: Rebuilding Rosewill 350W

So do you guys think I should gut the 200W newton or 200W astec?

This statement makes me cringe. They both sound too nice to destroy. But I guess if you must, then do so. Gut whichever has the parts that would work better with you.
I would rather fix those than the Deer, though.

Also with the new input coil, should I just solder in in to the same 4 holes as the current one?

If you want to, or you can use the other holes too. Just make sure that your coil is connected properly (look at the one you have currently in there and follow the wires). Basically you want to have both Live and Neutral pass through the coil, exit out at the other end, and continue to the bridge rectifier. If they "meet" inside the coil, you did it wrong. Use a DMM after you're done, set it to ohm test, and if there's a short between Live and Neutral, it's wrong.

Also, would there be any more of a improvement with it?

There should be. More coils means better suppression of EMI (in other words, your power supply will cause less interference to other electronics). Those coils also reduce some of the voltage spikes that could damage the primary capacitors.

It also wouldn't be a bad idea to try and make everell's circuit. It should fix that 5vsb for good. IC DM311 can be found on mouser for real cheap. Here's link:
http://www.mouser.com/Search/Product...iCCRoq4w%3d%3d

[370forlife]

Re: Rebuilding Rosewill 350W

Well, I recapped it with the caps from the newton (rubycon)

BEWARE. YC caps have cheap-ass plastic sheath that ripped off because of the massive amounts of spooge glue covering them. I had no idea what the ratings were, so I used 16v, 2200uf CEC caps (ran out of 16v rubycon's) parts in their place. Tested it, all is fine.

Also, it has 2 12v rails. I do believe it actually has 2 12v rails, as that is probalby what the 3rd transformer is. (maybe?) and I believe one rail was regulated by 2 16v, 1000uf YC parts, and the second by a single 16v, 470uf part. That was replaced by a 16v, 2200uf UCC part.

I was concerned at first because the voltages were more unstable than with the YC caps, but then I realized the caps from that psu have not seen power for about 5 years. After about a hour of running they smoothed out to 11.99v (12.00v dead on the 4pin cpu), 5.03v, and 3.33v. They still do the dip when they first start up, at first it was terrible down to 11.79, but after a while it now starts at about 11.89. Also, the 5vsb is now dead on 4.33v. I also replaced the unknown manufacturer fan with a adda 80mm fan.

[everell]

Re: Rebuilding Rosewill 350W

The middle transformer is a "driver transformer" or "interstage coupling transformer". It takes the pwm signal from the pwm chip and drives or couples to the two main switching transistors.

The 470 Mfd/16 volt capacitor in the "other" 12 volt rail is the -12 volt rail. You will notice that it connects to the blue wire. Putting a 2200 Mfd/16 volt capacitor there is a complete waste. This circuit is intended for LOW current. Your computer might not even be using the -12 volt rail. So you might as well put the 470 Mfd back and save that 2200 Mfd for another project.

[370forlife]

Re: Rebuilding Rosewill 350W

hmm, dang. Aww well, just put a 16v, 470uf teapo I have in the UCC's place.

[Newbie2]

Re: Rebuilding Rosewill 350W

370forlife, can you post pictures of your power supply now, after you have replaced the YC capacitors?

[370forlife]

Re: Rebuilding Rosewill 350W