Rosewill RP550-2-S

[everell]

Re: Rosewill RP550-2-S

Trying to fix that 5vsb circuit has gone nowhere. So I finally resorted to temporarily wiring an outboard 5vsb circuit. Powered it up, and all voltages present and measure good......but the psu is on even when it should be off. Started measuring voltages on the turn-on transistor switch and BANG. One of the switching transistors shorted and arced to one of the mains capacitors. Looks almost like arc welding. Damage to the capacitor case makes me suspicious that it is a goner. Also blew the fuse.

The outboarded 5vsb still works OK. But now will have to replace a switching transistor, a burned out resistor in its circuit, and maybe the pwm chip.

Now for the problem......the numbers on the transistors and chips have been removed (ground off). Does anyone have one of these with readable numbers? I will need to know switching transistors, pwm chip, and possibly the supervisory chip.

[everell]

Re: Rosewill RP550-2-S

Here is the pinout pattern of the transformer.

Left side, top to bottom: Ground, 5vsb

Right side, top to bottom: Common, feedback to main pwm chip, feedback power to pwm oscillator or pwm chip, drain of 5vsb transistor or pwm chip, and +320 volts from the mains capacitor.

[370forlife]

Re: Rosewill RP550-2-S

Can you post a quick description or picture of the pinout on the transformer? I got that AP-300 here doing nothing and I have no problem getting rid of it.

[everell]

Re: Rosewill RP550-2-S

I have done more testing on the 5vsb circuit components, and verified that the 5vsb transformer is bad. I removed the transformer from the pc board and put it in a different working circuit using the DM311 chip. Same results as when installed in original power supply. The winding to the switching transistor is OK, and the feedback windings are OK. The 5vsb secondary winding is the culprit, which puts out only 2 volts max with no load. Any added loading reduces the output voltage quickly. That explains why I measured only .8 volts on the 5vsb line in the original power supply.

The pin layout of the transformer is different from any transformer I have in my junkbox. As crowded as everything is in this power supply, I am on the lookout for a matching transformer. So check you junkbox for any 5vsb transformer labeled AP-500EPS or even AP-xxx from a ANTG power supply. Thanks.

[Toasty]

Re: Rosewill RP550-2-S

i hope you will complete the primary filter as well.... jumper wire bad! components good!

Look again.

[370forlife]

Re: Rosewill RP550-2-S

Ahh good ol' ATNG, always scratching off part numbers.

[everell]

Re: Rosewill RP550-2-S

To work on the 5vsb on this one required that I remove both heat sinks. So here are a couple of pictures. Both heat sinks are removed. The board does show a little bit of burn damage from the 5vsb blowups. All of the two transistor components have been removed. A DM311 mod board is temporarily installed with long leads to keep it out of the way while working on the circuit. Once I find a suitable 5vsb transformer, I can move this project further along.

[everell]

Re: Rosewill RP550-2-S

Is this something from your junk box? If so send it on and I will see if I can get it to fit and work. This psu is so compact and crowded it reminds me of a Antec SmartPower.

[370forlife]

Re: Rosewill RP550-2-S

AP-XXX is ATNG's in-house numbering system. This power supply is a AP series, 500 is just the mid range of what units that transformer is used in. 400-600W. ATNG is big enough to where they make their own transformers.

I have a ATNG AP-300 here. The 5vsb transformer is decently sized, marked AP-265N-1AT3.

[everell]

Re: Rosewill RP550-2-S

The 5vsb circuit is the trouble maker on this one. I tried doing a repair to the two transistor circuit, but it only blew out again. I installed a DM311 mod, but the output was only .9 volts. The feedback was over 2 volts so looks like the transformer is shot. Checked out components on the output side, and they were all OK. The main switching transformer and the 5vsb transformer both start with "AP". Not too sure who the OEM is. The 5vsb transformer number is AP-500EPS-T2-3, so check your junk box.

[goodpsusearch]

Re: Rosewill RP550-2-S

Very nice psu. It looks to have Teapo caps everywhere.

[370forlife]

Re: Rosewill RP550-2-S

I have the 450W ATNG branded version, it has 2x 40A schottky's on the 5v rail, so I think it the 550W version can do 50A on the 5v.

[Th3_uN1Qu3]

Re: Rosewill RP550-2-S

You mean that thing can actually do 50A on 15v? That's the highest 5v rating i've seen so far. Somehow i doubt that it's true - if it is, i gotta locate one for my dual-PIII.

[370forlife]

Re: Rosewill RP550-2-S

Yeah, the Y caps are in the input filter. Rosewill's ATNG units are pretty solid, it's their low end solytech units that are a little more "explosive"

[Per Hansson]

Re: Rosewill RP550-2-S

Quite impressive input filter for a Rosewill, guess I will need to adjust my opinion on them.
Also interesting location of the input filter, spanning all the way from what is usually regarded as the "primary" side over to the "secondary"
Because correct me if I'm wrong, but those Y-Caps on the right are part of the input filter right?

https://www.badcaps.net/forum/attach...5&d=1289105592

[370forlife]

Re: Rosewill RP550-2-S

I've got an identical ATNG branded unit (circa 2002, still works) if you need any part numbers or measurements.

[everell]

Re: Rosewill RP550-2-S

Good morning 370forlife. You posted while I was writing! No.....this is not a good ATNG unit. It does not work.

[everell]

Re: Rosewill RP550-2-S

The jumper wires on the input side are NOT for line filter.....they are for a PFC circuit which is not installed. The red jumper wire I added to take the place of the 115/230 volt switch.

Have not decided whether or not to do the DM311 mod........there just is not the usual amount of room for the add-on board which would go between the two heat sinks. Mounting the add-on board on the other side of the heat sink would cause BIG problems in how to route the wires.

My conclusion: they should have built it right in the first place. No surface mount components, two transistor 5vsb circuit, so this is probably some more Solytech crap.

[370forlife]

Re: Rosewill RP550-2-S

The input filter is complete, that jumper wire is for the optional APFC components.

By they way, this is a very good performing, but aging, ATNG unit.

Review for the 500W version:

http://www.jonnyguru.com/modules.php...Story2&reid=32

[c_hegge]

Re: Rosewill RP550-2-S

I wouldn't worry too much about the input filter. It looks good enough as it is.