Dell L350N-00/Liteon PS-6351-1DFS No Power

[TheRagnarok]

My dad found this power supply at a local dumpster "a bad sign already" and it won't power on, so I changed the fuse and got nothing. Then I tried connecting the green and black wires, while having a fan plugged into one of the molex connectors, but it would only spin for 1/2 a second. Also, there is a "click" sound coming from the power supply and the power supply fan doesnt spin. Can anyone give me some advice on this if it is "fixable" because this 350W would be alot nicer to use than my current 250W Bestec.

[Leopard]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

250W Bestec?? Get rid of that immediately before you have a shorted motherboard and burnt USB devices!

Usually a clicking sound tells that there's a short somewhere in the PSU. Inspect all capacitors, IIRC LiteON has used TAICON (along with good brands) which can be bad.

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

250W Bestec?? Get rid of that immediately before you have a shorted motherboard and burnt USB devices!

Usually a clicking sound tells that there's a short somewhere in the PSU. Inspect all capacitors, IIRC LiteON has used TAICON (along with good brands) which can be bad.

Thanks for the info on that Bestec, and how would I check the capacitors? "I'm new at this". Thanks.

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

I tried to find where the clicking sound was coming from with a mic, and it is emanating from the big "coil?". I circled it in this pic I found posted by "stevo1210" (I'm sorry, but I have no camera). Also, all of the capacitors "look" ok, but I dont even know how to test them. Could someone throw just a little sliver of advice over here? P.S. This Image belongs to "stevo1210".

[Gianni]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

Hi TheRagnarok

the big coil is the main power transformer.
If it makes a "click" sound probably there's a short circuit on the output.
Or maybe something is wrong with the outputs, an overvoltage occurs, and the PS shut down to avoid any damage to attached components.

If you are testing the PS without any load, it could be normal that it doesn't start and it makes the click sound: the start up capacitors charges until the PS Controller starts but, due to lack of load, the auxiliary voltage it is not enough to feed the controller so the PS shut down when the voltage on start up cap discharges to a low level. This cycle goes on as long as the PS is connected to line.
If you don't want to connect the PS to a mobo, try to connect an HD and a CD/DVD drive and check if with this minimum load the PS stays on.
If you have a DMM you can check if the stand by voltage is present: the output is the violet wire on the 20/24 poles connector and the negative is on the black wires.

Ciao
Gianni

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

@Gianni

Thanks for all of that information Gianni. Ok, I plugged-in all of my components (80gig WD SATA, 250gig WD IDE, LiteOn IDE DVD writer, and my XFX 8800 GS via the PCI-E power plug) into the power supply, and all that lit up (only for 1/2 a second) was my motherboard's built in power test LED. I don't know what a "DMM" is, so I just used my 6v-12v-24v car wire tester (a pointy screwdriver with a light bulb in it lol). Anyways, I hooked it to the violet wire/ground wire and it gave a constant stream of juice (the light was dim so it think it was in the 4v-8v range). Also, I'm running all of this stuff on my Biostar TF7025-M2 board with an AMD Athlon X2 4800, and 2gigs of A-Data DDR2 RAM, so I don't know how long this Bestec 250W will last. Maybe this PS from the dump will be helpfull, if I get it working.

[Leopard]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

A DMM is a Digital MultiMeter.
Cheap ones cost like $10 so go buy one from your local electronics store or someplace where you can get one and test if the standby voltage is present

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

A DMM is a Digital MultiMeter.
Cheap ones cost like $10 so go buy one from your local electronics store or someplace where you can get one and test if the standby voltage is present

Ok, kewlz my local Radio Shack is going out of business so I might get one at a discount lol. Thanks.

[stevo1210]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

I still have a Dell L350N-00 PSU.... It decided to crap out for a short period of time and for some reason works perfectly now.... but then again it only powers a 2GHz Celeron server now.
I don't think this is the case with yours though.... a DMM should tell you everything about the volatages though.

[kc8adu]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

the ticking tells me its trying to start into a short.
most likely one of the rectifiers on the secondary heatsink is shorted.
get a dmm with a doide test at the very least.
harbor freight has one they often put on sale for $2.99
get several in case of newbie mistakes.if you goof its expendible.

[Gianni]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

@ TheRagnarok: if you have attached some loads to PS and it still doesn't start and makes click sound than like kc8adu said there's probably a short circuit somewhere on the output and you should test output diodes.

If you don't find the short circuit than it becomes more complicated to troubleshoot the PS without a minimum of equipment (oscilloscope, LAB power supplies, DMM...).
In this post you can read how I proceed when I have to repair a PS.

Check also if there are bad joins.

Ciao
Gianni

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

@ kc8adu & Gianni, The rectifier closest to the 200v electrolytics was bad (I don't have a DMM yet so I used the car tester) and pin one wouldn't give me a connection. So I salvaged another rectifier from a wire-clipped power supply, soldered it on, and now it still only produces power for a 1/2 second. Also, it still gives out the standby voltage, but "something" shorted out the replacement resistor (I tested the salvaged resistor beforehand, and pin one was fine). ALSO, when I plugged it in after adding the replacement there was no power at all, as the 250v fuse had been blown (whatever fried the rectifier took the fuse out too) I had to replace the fuse to get a standby voltage from it. Radio Shack had no DMM's, so now I'm going to another nearby city to look for one (there are a few computer shops in that direction) so maybe they can point me to one.

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

@ TheRagnarok: if you have attached some loads to PS and it still doesn't start and makes click sound than like kc8adu said there's probably a short circuit somewhere on the output and you should test output diodes.

If you don't find the short circuit than it becomes more complicated to troubleshoot the PS without a minimum of equipment (oscilloscope, LAB power supplies, DMM...).
In this post you can read how I proceed when I have to repair a PS.

Check also if there are bad joins.

Ciao
Gianni

Thanks for that post you pointed out (allot of that stuff flew over my head though)

[Gianni]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

The rectifier closest to the 200v electrolytics was bad (I don't have a DMM yet so I used the car tester) and pin one wouldn't give me a connection.

It is not clear to me: how did you test it?
If nothing has changed, than the diode was not bad.
Did you replaced it with the same type?

but "something" shorted out the replacement resistor (I tested the salvaged resistor beforehand, and pin one was fine).

Also this one is not clear to me: how did you checked the resistor without a DMM?
What do you mean with "pin one was fine"?

Ciao
Gianni

[Leopard]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

While you're at it, you should replace those Elite branded primary capacitors just in case. Elite is one of the worst brands...

E: Oh, sorry, didn't remember that the pic isn't taken of your power supply. Well, if they're the same Elite caps then replace them.

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

It is not clear to me: how did you test it?
If nothing has changed, than the diode was not bad.
Did you replaced it with the same type?


Also this one is not clear to me: how did you checked the resistor without a DMM?
What do you mean with "pin one was fine"?

Ciao
Gianni

I'm sorry for my implied ignorance, but here is what I used in place of a DMM. Also, there is the rectifier in question. I put the negative(the end with bare wire) end on pin 4, and the positive(the end with lightbulb tester) end on pin's 1,2,and 3. Pin 1 didn't pass, pins 2 and 3 passed. And before i put the replacement rectifier in, I tested the pins. And pins 1,2, and 3 were all fine. But, after I soldered it on I got nothing, so I replaced the fuse and got a standby voltage. Also, I de-soldered the replacement, and found that pin 1 had been tainted. So now I know that something is frying pin 1 on the rectifier.

I went digging and found a Veo webcam in my closet lol.

[Wizard]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

Are you using a high speed rectifier?

These have two diodes with cathodes on center pin.

And no, should not pass any on 1 to 3 in either direction, but you should able to have polarity on 1 and 2 and 2 and 3. That done unsoldered from board.

Cheers, Wizard

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

I've given up all hope of repairing the Dell PS "for now it's perched atop my old Compaq branded CRT". I decided to get this Antec earthwatts EA430 430W PS from newegg for $39.99 w/ free shipping "I bought it this morning for $39.99, but now it's at $49.99". Also, thanks for all the informative answers to my otherwise curiously stupid questions.
http://www.newegg.com/Product/Produc...82E16817371006 There's the one I ordered. I can also say that the Bestec will be retired when it's replacement arrives.

[Gianni]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

TheRagnarok if I'm not wrong, looking at the picture, the components is not a diode but FQA11N90 , it is a PowerMosfet from Fairchild.
Probably something is wrong with the driver if you find pin 1 (Gate) damaged.

Hope your new purchase will satisfy you.

Ciao
Gianni

[TheRagnarok]

Re: Dell L350N-00/Liteon PS-6351-1DFS No Power

TheRagnarok if I'm not wrong, looking at the picture, the components is not a diode but FQA11N90 , it is a PowerMosfet from Fairchild.
Probably something is wrong with the driver if you find pin 1 (Gate) damaged.

Hope your new purchase will satisfy you.

Ciao
Gianni

Great.... Now I'm curious..... again!. What on earth is a "driver", and where would it be? Why do you torture me? Thanks.