LINKWORLD LPQ6-300WP modding. Any suggestions?

[goodpsusearch]

I decided to fully recap that psu. I think it could be a decent unit for a 5V system.

More than that, making it better in more ways than recapping would be a nice learning project for me.

It has a full input filter, passive pfc, large 35 size transformer, 1 mosfet STP9NC60 and 2SC5353 for 5vsb. Secondary has 30A schottky rectifier (SBL3040PT) @5V, 20A (SBL2040CT) @3.3V, 16A (STPR1620CT) @12V.

In primary side there are 4 diodes 1N5406 rated 3A. I am thinking of replacing them with a bridge rectifier.

I noticed that there are coils missing from 5vsb and 3.3V output filters. Can I put coils from other psus there?

Primary caps are 330uF 200V. I wonder if I could replace them with 680uF 200V ones...

Other changes I would like to do:
5vsb: 2x470uF 16V --> 2x1000uF 10V/16V
3.3V: 2x2200uF 10V --> 2x2200/2700uF 10V
5V: 2x1000uF 10V --> 2x2200/2700uF 10V
12V: 2x470uF 16V --> 2x2200uF 16V

What do you think?

More photos can be found here:
https://www.badcaps.net/forum/showpo...85&postcount=2

Any help/suggestion welcome

[370forlife]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

It has a full input filter, passive pfc, large 35 size transformer, 1 mosfet STP9NC60 and 2SC5353 for 5vsb. Secondary has 30A schottky rectifier (SBL3040PT) @5V, 20A (SBL2040CT) @3.3V, 16A (STPR1620CT) @12V.

In primary side there are 4 diodes 1N5406 rated 3A. I am thinking of replacing them with a bridge rectifier.

Definitely replace diodes with bridge rectifier. Looks like you can add second rectifiers to the 5v and 3.3v rails too. Try to get two identical 20A's or 30A's for the 5v (doubles capacity and reduces heat) 3.3v dosen't need it as much, but 20A is a bit low. I would get two identical 20A's for that one.

I noticed that there are coils missing from 5vsb and 3.3V output filters. Can I put coils from other psus there?

Primary caps are 330uF 200V. I wonder if I could replace them with 680uF 200V ones...

Yes and Yes.

Other changes I would like to do:
5vsb: 2x470uF 16V --> 2x1000uF 10V/16V
3.3V: 2x2200uF 10V --> 2x2200/2700uF 10V
5V: 2x1000uF 10V --> 2x2200/2700uF 10V
12V: 2x470uF 16V --> 2x2200uF 16V

Nice job upgrading the capacity.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

I need some help choosing the right coils and caps for the output filters.


At 12V I am planning to put these caps:
http://gr.rsdelivers.com/product/pan...v/0571606.aspx
Esr of original 470uF 16V Capxon caps is 0,14.
I need to know if it is ok to increase capacity and lower the esr that far.


I have 4 of those caps in stock:
http://gr.rsdelivers.com/product/pan...v/0571284.aspx
Can I use them to replace the originals?
3.3V: 2x2200uF 10V CS LOW ESR esr measured on board: 0.01
5V: 2x1000uF 10V Fuhjyyu TMR esr measured on board: 0.04

What coil do you recommend to put at 3.3V filter from those 3 dead psus?

Antec SP 450W

Jou Jye 300W: 1 , 2

Enlight 250W


For 5vsb I have those caps in stock:
http://gr.rsdelivers.com/product/pan...f/5261115.aspx
Can I use them to replace 470uF 16V Capxon caps (esr 0,14) and what coil should I choose of those 2?

Antec SP 450W 5vsb coil

Jou Jye 300W 5vsb coil


Thanks for your help!

[momaka]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

What coil do you recommend to put at 3.3V filter from those 3 dead psus?

Just use whatever coil was on the 3.3v rail of the donor PSU. The ones in the Antec and Enlight PSU might be better since they have a ferrite core. This increases the overall inductance of the coil.

For 5vsb I have those caps in stock:
http://gr.rsdelivers.com/product/pan...f/5261115.aspx
Can I use them to replace 470uF 16V Capxon caps (esr 0,14) and what coil should I choose of those 2?

FM would probably be okay. As for the coil, again use whatever was in the 5vsb of either the Antec or the Jou Jye.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

The new big caps (680uF Jun Fu, same with those: https://www.badcaps.net/forum/attach...chmentid=14580) don't match the holes of the psu....

[momaka]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Do you have any small drill bits? Most PSUs have large traces on the primary side so it might be possible to drill new holes.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Do you have any small drill bits? Most PSUs have large traces on the primary side so it might be possible to drill new holes.

I used a screwdriver to widen 1 of the holes of every cap.

Then I used as much solder possible to make sure it will not break/loose contact.

This is the best I could do... I hope it isn't very bad.

[370forlife]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Looks fine.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Hello!

Replacement caps arrived yesterday, so I fully recapped and put filter coils in that psu.

One last thing that I feel I would like to do is add some protection in the input filter. I noticed that this psu doesn't have a mov, only a thermistor.

So, I have taken out from the dead jou jye 300W, those yellow parts that if I am not wrong are metal oxide varistors. They were placed among the big input caps at "znr1" and znr2" place on board.

I wonder if I can place them in "znr3" and "znr4" place at linkworld (see photo ).

Thank you for your help and support

[370forlife]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Yup, those look like MOV's to me.

I would think znr3 and znr4 are where they would go. Thats where they are in most of the psu's I have.

[momaka]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

One of the two 200v caps looks bulged (picture 6, the one further from the bridge rectifier). Or is that just how the picture came out?

Otherwise it looks good with those new Pannys. Maybe if you have some 1mm (or thicker) aluminum around, you can make a heatsink for U302 (5vsb transistor).

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Yup, those look like MOV's to me.

I would think znr3 and znr4 are where they would go. Thats where they are in most of the psu's I have.

I added them there!

One of the two 200v caps looks bulged (picture 6, the one further from the bridge rectifier). Or is that just how the picture came out?

It's just the picture.

Otherwise it looks good with those new Pannys. Maybe if you have some 1mm (or thicker) aluminum around, you can make a heatsink for U302 (5vsb transistor).

I'm not sure how I could do this..

The transistor is C5353 (DC 3A, pulsed 5A). Maybe is it capable of 2A output without a heatsink?

What are the normal values of 5vsb and main transistors in a 300W psu?

[370forlife]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

5vsb is typically rated at 1-2A on older designs, 2.5-3A on newer ones. It's not used for much, some motherboards use it to power the usb ports thats about it.

This power supply only has the one primary switcher in a singe transistor forward configuration. My HEC 585W that is really a 300W will do 350W before the OCP trips and it's primary switcher is rated at 10A @ 25C or 5.7A @ 100C.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

The primary switcher in linkworld is STP9NC60 rated at 9A @ 25C, 5.7A @ 100C.

[370forlife]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Should be fine then.

[goodpsusearch]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

Done with that psu!

I tested it and found all the voltages to be very stable and right.

I was also glad to find out that the new caps in secondary were small enough in order not to have problems with passive pfc above them (photo attached).

I would like to thank you one more time for your help.

[momaka]

Re: LINKWORLD LPQ6-300WP modding. Any suggestions?

It's just the picture.

That's what I thought too, but just wanted to make sure.

I'm not sure how I could do this..

The transistor is C5353 (DC 3A, pulsed 5A). Maybe is it capable of 2A output without a heatsink?

Should be okay. I get a better feeling of security when components have heatsinks attached to them, but that's just me .