Just got another L&C.....

[c_hegge]

Re: Just got another L&C.....

If it stays bright, then you have a short on the primary side, and the thing would have blown up if plugged in directly.

[Dan81]

Re: Just got another L&C.....

Use a 60 watt incandescent light bulb in series with the mains input. This should help protect things if it does want to blow up again. You'll notice it glow for a moment, that is from the filter capacitors charging up, but it should dim down a little in a few seconds (or less).

But what if it stays bright?

[ben7]

Re: Just got another L&C.....

Just replaced the diodes,primaries,balancing resistors and 2 secondary resistors.

Diodes - 4A bridge rectifier
Balancing resistors - replaced with good ones from a better Deer (sounds ironic,doesn't it?)
Primaries - 470uf 200v YC - 330uf 200v YC from a 2006 Deer (that seems to have PI coils)
Transistors - 2x C4106 - 2x D13007.
Fuse - replaced

Installed these yet I am reluctant to turn on the PSU,as I think (but I may not be right) it will blow again.

Use a 60 watt incandescent light bulb in series with the mains input. This should help protect things if it does want to blow up again. You'll notice it glow for a moment, that is from the filter capacitors charging up, but it should dim down a little in a few seconds (or less).

[Dan81]

Re: Just got another L&C.....

Just replaced the diodes,primaries,balancing resistors and 2 secondary resistors.

Diodes - 4A bridge rectifier
Balancing resistors - replaced with good ones from a better Deer (sounds ironic,doesn't it?)
Primaries - 470uf 200v YC - 330uf 200v YC from a 2006 Deer (that seems to have PI coils)
Transistors - 2x C4106 - 2x D13007.
Fuse - replaced

Installed these yet I am reluctant to turn on the PSU,as I think (but I may not be right) it will blow again.

[Dan81]

Re: Just got another L&C.....

check the rectifier diodes for shorts.

Checked. None are shorted.

[stj]

Re: Just got another L&C.....

check the rectifier diodes for shorts.

[Dan81]

Re: Just got another L&C.....

Sorry,but I threw away the YC caps after I replaced the capacitors.

Also,have to do some more work on it,since the first time I replaced the primaries the PSU did a pop and a small spark (not that bad like the 350W one). The fuse blew (splatter inside it). I replaced both fuse and NTC thermistor to be sure,and installed CapXon primaries (before cap plague,datecodes are 1996-1998 on them) from a dead AT PSU. I'm reluctant to test it yet because of the sparks the previous one did. (they were real scary,this one was just a simple pop,no fireballs or such)

[ben7]

Re: Just got another L&C.....

Scrapped the 350w and got another one,a JNC LC-B300ATX.

This one didn't spark though. No diode-on-a-bracket for 12v,but a "SF1004G" 10A rectifier instead - sounds good to me. No PI coils though (going to install them),but I like that it has good sized toroids,AC input filtering and at least all the PI coils spaces are marked. Will work on it.

It doesn't turn on - the cause is a bulged primary cap - 470uf 200V Yang Chun. The other seems fine though.

Caps are all G-Luxon on the 5vsb and secondary side,with a lone Canicon TC 2200uF 16V on 12v.

Board marked Y-B2002 ATX Ver 2.3,PWM chip is 2003.

Wiring is 16AWG mostly,with 20AWG for the HDD/ODD wires,and 18AWG for the 12V P4 plug.

Ooo, could you take a pic? We don't see bulged primary side caps too often! :P

P.S. Be sure to check the balancing resistors to see if they are OK. If one is O/C, that will cause the replacement capacitor to fail, no matter what brand/quality it is.

Nice to see that it has some 16 gauge wire.

[Dan81]

Re: Just got another L&C.....

Scrapped the 350w and got another one,a JNC LC-B300ATX.

This one didn't spark though. No diode-on-a-bracket for 12v,but a "SF1004G" 10A rectifier instead - sounds good to me. No PI coils though (going to install them),but I like that it has good sized toroids,AC input filtering and at least all the PI coils spaces are marked. Will work on it.

It doesn't turn on - the cause is a bulged primary cap - 470uf 200V Yang Chun. The other seems fine though.

Caps are all G-Luxon on the 5vsb and secondary side,with a lone Canicon TC 2200uF 16V on 12v.

Board marked Y-B2002 ATX Ver 2.3,PWM chip is 2003.

Wiring is 16AWG mostly,with 20AWG for the HDD/ODD wires,and 18AWG for the 12V P4 plug.

[Dan81]

Re: Just got another L&C.....

^
on the 12V? No. The VRRM (Peak Reverse Repetitive Voltage) should be 100V or higher. You may get away with 60V, but not 40V link on the SBL3040PT. Something like an MBR20100 would probably work fine.

Oh. Okay then.

[c_hegge]

Re: Just got another L&C.....

^
on the 12V? No. The VRRM (Peak Reverse Repetitive Voltage) should be 100V or higher. You may get away with 60V, but not 40V link on the SBL3040PT. Something like an MBR20100 would probably work fine.

[Dan81]

Re: Just got another L&C.....

Look at that pic.... the current sensing (?) resistor, to the right of the heatsink, by the base of the big cap, has two holes in it. It might be hard to see at first, but give a good look at it and you will see them!

I've looked good enough and indeed there are two holes. Didn't notice first time.

Thanks for pointing that out!


Also,planning to replace the two diodes after getting it to work. Would a SBL3040PT in there?

[ben7]

Re: Just got another L&C.....

Because of missing PI coils? If so I added them to the board.

Also just because a PSU is bad it doesn't mean it can't be improved.

Oh yeahhh, you could go full-out on that sucker! Mod 'er up!

If that thing really was new, my guess is that a bad solder joint caused the failure. Open circuits can be just as troublesome as closed (shorted) circuits! :P

EDIT: HOLY CRAP

this area.

Look at that pic.... the current sensing (?) resistor, to the right of the heatsink, by the base of the big cap, has two holes in it. It might be hard to see at first, but give a good look at it and you will see them!

[c_hegge]

Re: Just got another L&C.....

^
Ah. OK. That will help a lot.

[Dan81]

Re: Just got another L&C.....

That thing can not deliver a single watt of power in spec.

Because of missing PI coils? If so I added them to the board.

Also just because a PSU is bad it doesn't mean it can't be improved.

[c_hegge]

Re: Just got another L&C.....

That thing can not deliver a single watt of power in spec and is nothing but a poorly built motherboard and HDD killer. The only thing that will improve that PSU is a sledgehammer.

[everell]

Re: Just got another L&C.....

The three components stj circled are the snubber circuit (diode, capacitor, and resistor). From the picture of the bottom of the pc board, it looks like one of the legs of the capacitor is not well soldered.

Check that diode. If it is shorted it can cause these symptoms. Sometimes the manufacturer uses a 1N4007 diode which is a slow poke at these frequencies. So they tend to short over time. A lot of these cheap power supplies use a FR107 diode (FR meaning fast recovery) and are OK for this circuit.

[Sparkey55]

Re: Just got another L&C.....

You need to use a dim bulb tester in line with the power input side just incase of a short circuit still exists.

[goodpsusearch]

Re: Just got another L&C.....

that's not the point, yuo need to find out what it sparked to/from and test every part related to that circuit.

+1

In cases like that you need to check everything or else it will blow again when you connect it to mains.

[stj]

Re: Just got another L&C.....

that's not the point, yuo need to find out what it sparked to/from and test every part related to that circuit.