Rexpower PL-400 rebuild

[momaka]

Re: Rexpower PL-400 rebuild

Get rid of that big load resistor on the 3.3v rail. Looks like a 10 Ohm. If it is, that's almost 1W of heat there and you'll be cooking your new caps. Change it with a different resistor that's 25 Ohms or more (but not more than 500 ohms). Seems like the 5vsb also has a big loading resistor (51 Ohms?). Change it to 100 Ohms or a bit higher. Less heat and improved efficiency when the PSU is loaded.
See if there are any other load resistors on the other rails.

PSU looks solid.

[370forlife]

Re: Rexpower PL-400 rebuild

It actually had schottkys for the other two rails (Mospec S20C40C). The only fast recovery was the F12C20C on the 12v. As a replacment for the 12v rail, would an 80EPF10 do the job? (80A, 1000v VRRM)

I believe etnietering tried using a Ultrafast 250v in place of a 200v Ultrafast on the 12v rail of his logisys 480W he was rebuilding and it failed to start up with it installed.

Something like a 40A, 45V or 60V schottky would work fine. Using two 20A schottky's would be best as they would produce less heat, but a single to-247 40A or even a 30A would work just fine.

[c_hegge]

Re: Rexpower PL-400 rebuild

There's only room for 1 on the 12v rail. The 5v is the only rail where two can be installed. Would the STPS3045CW work fine or would a 48CTQ060PBF be better?

[370forlife]

Re: Rexpower PL-400 rebuild

The 48CTQ060PBF is in to-220 form and can do 40A at 110C. The STPS3045CW is in to-247 and can do 30A at 155C. Now because you won't reach 110C in the PSU it will probably be fine to use the 48CTQ060PBF.

[c_hegge]

Re: Rexpower PL-400 rebuild

I've given it some additional modifications. It previously had a thermister in series with the fan to temperature control it. I've replaced that with a proper temperature controller I pulled from an failed antec SU-380. I also have replaced all of the connectors (the originals only had 20 guage wires). It now has a 24 pin ATX connector, 8 SATA connectors, 6 Molex connectors and 2 floppy connectors.

[goodpsusearch]

Re: Rexpower PL-400 rebuild

I've given it some additional modifications. It previously had a thermister in series with the fan to temperature control it. I've replaced that with a proper temperature controller I pulled from an failed antec SU-380. I also have replaced all of the connectors (the originals only had 20 guage wires). It now has a 24 pin ATX connector, 8 SATA connectors, 6 Molex connectors and 2 floppy connectors.

Great job!

I would love to see some photos

[c_hegge]

Re: Rexpower PL-400 rebuild

It aint finished yet. I'm still waiting on that 12v schottkey diode to arrive. I placed a few on back order from RS compunents (they didn't have it in stock).

[shovenose]

Re: Rexpower PL-400 rebuild

I hate waiting for stuff to arrive - its frustrsting!

[c_hegge]

Re: Rexpower PL-400 rebuild

Unfortunately the 48CTQ060PBF is discontinued. I was just informed by RS this morning, so I'm going to have to find an alternative part to use. Would a BYV42E-200 200V Ultrafast work?

[goodpsusearch]

Re: Rexpower PL-400 rebuild

I think it should be ok but better wait for others with more experience to respond, for example 370forlife.

[everell]

Re: Rexpower PL-400 rebuild

What about the 5vsb circuit? If it fails, everything goes down the tube. Now might be a good time to try getting rid of that two transistor 5vsb circuit and installing a pwm chip.

[370forlife]

Re: Rexpower PL-400 rebuild

Unfortunately the 48CTQ060PBF is discontinued. I was just informed by RS this morning, so I'm going to have to find an alternative part to use. Would a BYV42E-200 200V Ultrafast work?

I would imagine it would work.

[Th3_uN1Qu3]

Re: Rexpower PL-400 rebuild

You don't really need a 200v part, a 100v one would work fine. MBR30100. But the one you linked to will work just fine as well. It has a bit higher voltage drop, but it'll do fine since i doubt the transformer in that can do 30A.

[370forlife]

Re: Rexpower PL-400 rebuild

Sometimes the cheap power supplies will have a hard time using a regular schottky on the 12v rail. It will just act like there is a short, and only a ultrafast can be used. Rather be safe than sorry.

[c_hegge]

Re: Rexpower PL-400 rebuild

Done for now. I might give it the 'everell mod' to the 5vsb later. Feel free to laugh at my new label. I'll test it when I get brave enough to power it on

[everell]

Re: Rexpower PL-400 rebuild

I really like that "cool" double fan arrangement!

[goodpsusearch]

Re: Rexpower PL-400 rebuild

It looks great

[momaka]

Re: Rexpower PL-400 rebuild

Looks good indeed. Is the secondary heatsink from a HiPro PSU?

I'll test it when I get brave enough to power it on

I was like that about 1 year ago. Now I just plug in things without getting any second thoughts. Not sure how that happened. I guess I eventaully got over it once I did a few repairs.
With that said, fire that s*** up and let it burn if it so desires .

[Th3_uN1Qu3]

Re: Rexpower PL-400 rebuild

I really like that "cool" double fan arrangement!

Believe it or not i've seen it on gutless wonders before.

[c_hegge]

Re: Rexpower PL-400 rebuild

The primary heatsink is from a Hipro, but the secondary is from a Seasonic-OEM Antec SU-380.