Replacing 4 diodes with a bridge

[Pentium4]

Re: Replacing 4 diodes with a bridge

I would have left them if they were standing up but I don't think they'd stay cool enough like that

[ben7]

Re: Replacing 4 diodes with a bridge

Another 4 diode replacement... just wanted to double check to make sure this is correct

Yep it's correct.

[Pentium4]

Re: Replacing 4 diodes with a bridge

Another 4 diode replacement... just wanted to double check to make sure this is correct

[Pentium4]

Re: Replacing 4 diodes with a bridge

You guys have good points, and they probably don't care either way

[mariushm]

Re: Replacing 4 diodes with a bridge

They're easier to ship and package that way, take less space.
Easier to handle in the factory.
Can be reused in other designs where there are tall parts near the heatsinks

[cheapie]

Re: Replacing 4 diodes with a bridge

Thanks, I'm glad you approve! I don't understand why they don't do that from the factory

Because it adds about a tenth of a cent worth of wear to the machine! Think about it: if they make 10,000 units, that's an entire TEN DOLLARS that they save!

[Pentium4]

Re: Replacing 4 diodes with a bridge

Not bad. I always bend those fins outwards too. The stock configuration is hopeless for getting airflow between the two rows of fins.

Thanks, I'm glad you approve! I don't understand why they don't do that from the factory

[c_hegge]

Re: Replacing 4 diodes with a bridge

Not bad. I always bend those fins outwards too. The stock configuration is hopeless for getting airflow between the two rows of fins.

[Pentium4]

Re: Replacing 4 diodes with a bridge

Was pretty frustrated, I went to put those MBR20100CT's in the PSU, even had them bolted to the heatsink and the legs were too short on them So I left the original one....

Here is the final picture with the new diode, a Panaflo DC Brushless fan, the new caps (Except the -12V and -5V) and I also bent the fins on the heatsinks outwards, I think they will cool better this way. Now hopefully this thing can last in a computer I only trust it up to 200W for long periods of time

[Pentium4]

Re: Replacing 4 diodes with a bridge

Or just worked with a very low load? I hope Khron is right in the fact that the reverse voltage is a little lower but shouldn't affect it. After recapping it I plan on replacing the TOBA MUR1620CT with two MBR20100CT's in parallel to reduce some of the heat on that little heatsink...

[ben7]

Re: Replacing 4 diodes with a bridge

Thanks for the replies Really? Because it got 5VSB but wouldn't power up. I will see how it goes! The SB540 is mounted to a little heatsink that should help

Edit: Woohoo it powers up now! Now I can continue modifying it in confidence

Um, wtf. Maybe it was somehow being rectified some way, but not well.

[Pentium4]

Re: Replacing 4 diodes with a bridge

Thanks for the replies Really? Because it got 5VSB but wouldn't power up. I will see how it goes! The SB540 is mounted to a little heatsink that should help

Edit: Woohoo it powers up now! Now I can continue modifying it in confidence

[Khron]

Re: Replacing 4 diodes with a bridge

40V vs 60V reverse voltage rating shouldn't be much of a problem, in this case. Judging by the location next to the 5Vsb transformer, i'd say it's a safe bet this is the 5Vsb rectifier

[ben7]

Re: Replacing 4 diodes with a bridge

I had suspicions about this diode being shorted so I took it out and it measured 1.3Ω both ways, is it bad? It's an SB560 diode

Yep, it indeed is bad.

[Pentium4]

Re: Replacing 4 diodes with a bridge

I had suspicions about this diode being shorted so I took it out and it measured 1.3Ω both ways and it diode check mode it reads 0 both ways, is it bad? It's an SB560 diode. And I have an SB540, would that be a suitable replacement?

[Pentium4]

Re: Replacing 4 diodes with a bridge

Not sure what your plans for that PSU are Pentium4, but it appears to be very similar (although slightly cheaper judging from the heatsinks) to this one I rebuilt a while back if you want some ideas.
https://www.badcaps.net/forum/showth...hlight=gutless
Hey, thank you very much for the link, i wish mine had heat sinks like yours
link directly to the rebuild post:https://www.badcaps.net/forum/showpo...93&postcount=8

Can you please stop hijacking P4's thread?

Haha, thanks

Hi P4

the cap that is in it is only rated at 85 deg so I would up grade to 105 deg the peak esr 70 is showing that the cap is within spec (ie 20%+or-)

I would replace it anyway where there any other components blown it the primary side of this PSU? if so you will need to replace them as well then you need to check the secondary side.

Good luck with your project.

Yeah, I will for sure replace all the caps in this thing! I don't trust any of the ones that came in it I will keep this thread updated

[popeye]

Re: Replacing 4 diodes with a bridge

Yeah! Here is the before and after, and a pic of a typical Chinese cap lying about the specs! I think maybe some of the little caps on the 5VSB are bad because this thing has no signs of life. I will work on it more on the 31st and hopefully get it going

Hi P4

the cap that is in it is only rated at 85 deg so I would up grade to 105 deg the peak esr 70 is showing that the cap is within spec (ie 20%+or-)

I would replace it anyway where there any other components blown it the primary side of this PSU? if so you will need to replace them as well then you need to check the secondary side.

Good luck with your project.

[TELVM]

Re: Replacing 4 diodes with a bridge

Ouch, my apologies.

[ben7]

Re: Replacing 4 diodes with a bridge

Can you please stop hijacking P4's thread?

[Tube_Dude]

Re: Replacing 4 diodes with a bridge

Man that capacitance/ESR gadget is exactly what I'm looking for ! Where can I get one of these? How much does it cost?

You can buy it directly from PEAK, like I have done. They ship very fast.

And yes, I love my ESR 60 analyser...

http://www.peakelec.co.uk/acatalog/jz_esr60.html