PREMIER model DR-8460BTX 450W PSU recap

[stefos]

Hello !!!

I got this psu from a friend and even there are many bulged caps, psu is still working but with stability issues as expected.

Even is a cheap one model, it's an opportunity to a newbie like me to proceed on recapping as this is the easy part of the work but....

I have read many threads so far about psu improvements and I wondering how this model can be improved. What parts do I have to replace and get e.g. better stability or watt output ?

Thanks a lot.

[stj]

Re: PREMIER model DR-8460BTX 450W PSU recap

i bet that "35" on the main transformer means it's really rated for 350w!!!

[goodpsusearch]

Re: PREMIER model DR-8460BTX 450W PSU recap

This is almost identical with the Premier psu I had once.

Take a look at the post I made after the improvements I applied:

https://www.badcaps.net/forum/showth...607#post109607

[momaka]

Re: PREMIER model DR-8460BTX 450W PSU recap

Improvements?

- Change all of the electrolytic caps, including the very small ones. The big 200V ones will be expensive, so you can leave them if you want, but their real capacitance is probably closer to 330 uF than 470 uF, so that will limit you to no more than 200W power draw.
Most importantly, there will be a 50V 22 uF and/or 50V 47 uF for the 5VSB "critical" cap - make sure you definitely replace this one. Otherwise the 5VSB can go out of control and kill the motherboard over time.

- Remove and shuffle around the large load resistors on the output because they tend to run hot and cook the caps. These are usually 100 Ohms on the 12V rail, 47 Ohms on the 5V rail, and anywhere between 6.8 and 10 Ohms on the 3.3V rail. Remove the 6.8-10 Ohm resistor from the 3.3V rail and put the 47 Ohm in its place, then remove the 100 Ohm from the 12V rail and put it on the 5V rail. Leave the 12V without anything or use any resistor rated for more than 1/2W and at least 500 Ohms resistance.

Everything else is okay for the most part.

i bet that "35" on the main transformer means it's really rated for 350w!!!

That's a "fake" 35-size transformer. It's actually a 33. More like 250W max to keep it safe. With 35 you can do 300-350W depending on design... but with a half-bridge with 2x 13007's, it's better to stay below 300W total draw from the wall to keep it safe.

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

I have replaced all of the electrolytic caps except the two big filter caps because I didn't want to spend too much value for this cheapy psu.

Filter caps measured at 321uf and 337uf with 0.58 Ohms ESR. The small one was rated 50v 2.2μf

Also I resolder the large load resistors on the output as suggested from friend momaka. The default registor values was for 12v -->117.8 Ohm, for 5v -->28.5 Ohm and for 3.3v -->15.8 Ohm.

At 12v I used 330 Ohm registor from another Premier psu and test it with hard disk load. Compared voltage outputs (b)efore and (a)fter the registor shuffle. All where steady

a) 12v--> (b) 12.49v (a) 12.51v
b) 5v--> (b) 3.363v (a) 3.365v
c) 3.3v--> (b) 5.181v (a) 5.183v

Finally replaced with a lube silent fan.

[Pentium4]

Re: PREMIER model DR-8460BTX 450W PSU recap

Very nice! Yes I'm sure the big 200V caps are fine. I know you probably used OIFA caps because this is a cheap PSU, although I will say I do not recommend at all using CapXon on the 5VSB.

Did the original fan fail? With the fan always running so fast @ 12V, I can't see how it would get that hot without the fan failing.

Also, if you haven't already, I would replace those non-safety approved Y caps on the input with some safety approved ones, or just remove them altogether

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

Did the original fan fail? With the fan always running so fast @ 12V, I can't see how it would get that hot without the fan failing.

The original fan was full of dust and was rotating hardly. I clean it but produced a buzzing sound while spinning.

Thank you all for you suggestions !!!

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

a) 12v--> (b) 12.49v (a) 12.51v
b) 5v--> (b) 3.363v (a) 3.365v
c) 3.3v--> (b) 5.181v (a) 5.183v

a) 12v--> (b) 12.49v (a) 12.51v
b) 5v--> (b) 5.181v (a) 5.183v
c) 3.3v--> (b) 3.363v (a) 3.365v

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

Improvements?
Most importantly, there will be a 50V 22 uF and/or 50V 47 uF for the 5VSB "critical" cap - make sure you definitely replace this one. Otherwise the 5VSB can go out of control and kill the motherboard over time.

This psu uses 2.2uf 50v caps for the +5vsb. Is it better to use this value or 22uf and/or 47uf?

Leave the 12V without anything or use any resistor rated for more than 1/2W and at least 500 Ohms resistance.

If leave the 12v without anything won't this affect psu stability?

Thanks for you help.

[stj]

Re: PREMIER model DR-8460BTX 450W PSU recap

is that X-Fan the original or the replacement?

i'v seen them selling pretty cheap and wondered how good they are.

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

is that X-Fan the original or the replacement?

i'v seen them selling pretty cheap and wondered how good they are.

The replacement x-fan works smoothly and quite silently in comparison with the original fan.

[stj]

Re: PREMIER model DR-8460BTX 450W PSU recap

right, i think i'l get a couple.
http://www.rapidonline.com/electrica...bearing-539453

[momaka]

Re: PREMIER model DR-8460BTX 450W PSU recap

This psu uses 2.2uf 50v caps for the +5vsb. Is it better to use this value or 22uf and/or 47uf?

I doubt the 5VSB critical cap is 2.2 uF. Deer almost always uses 10/22/47 uF. Look again at the small cap in the upper-right corner of this picture (right under the AC wires):
https://www.badcaps.net/forum/attach...1&d=1400876807
That small cap is the critical 5VSB cap. Check what it says on it again.
The 2.2uF caps you're talking about I'm guessing are the smaller caps that are together near the small transformer in the middle. These are for the base-drive circuit for the BJTs in the main power supply.

In any case, keep all capacitance values the same for these small caps.

For the output of the power supply, it's best to get 2x 2200 uF for the 3.3V and 5V rails and at least a single 2200 uF cap for the 12V rail.

If leave the 12v without anything won't this affect psu stability?

If running the PSU without any load, maybe. But with a motherboard attached, it won't be a problem. This PSU does its regulation mostly around the 5V rail. As long as the 5V rail has some load on it, the PSU will be stable in most cases.

[stefos]

Re: PREMIER model DR-8460BTX 450W PSU recap

I doubt the 5VSB critical cap is 2.2 uF. Deer almost always uses 10/22/47 uF. Look again at the small cap in the upper-right corner of this picture (right under the AC wires):
https://www.badcaps.net/forum/attach...1&d=1400876807
That small cap is the critical 5VSB cap. Check what it says on it again.
The 2.2uF caps you're talking about I'm guessing are the smaller caps that are together near the small transformer in the middle. These are for the base-drive circuit for the BJTs in the main power supply.

In any case, keep all capacitance values the same for these small caps.

For the output of the power supply, it's best to get 2x 2200 uF for the 3.3V and 5V rails and at least a single 2200 uF cap for the 12V rail.


If running the PSU without any load, maybe. But with a motherboard attached, it won't be a problem. This PSU does its regulation mostly around the 5V rail. As long as the 5V rail has some load on it, the PSU will be stable in most cases.

Dear friend thank you a lot for your advise !!!

I opened again the case and saw that replaced cap value is 22uF and other two capacitors near the small transformer value is 2.2uF.