atx YLP-013 Repair help please

[humblesmith1]

I have a YLP-013
power supply I'm trying to repair.
Can anyone help me with a parts list or schematic?
The PCB says YLP-013 Rev 2.1
No real manufacturer listed on the case but says 400 watts.

[370forlife]

Re: atx YLP-013 Repair help please

Whats up with these lately?

This is a yuelin built unit. I have done rebuilds on a couple of YLP-013's now. Fire away.

Pictures are always good, too.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks for the reply.

I have a lot of electronics experience and just need a part number for Q7 so far.

It has the top blown off and I can't read the part number.

Do you have a schematic or parts list?

Thanks

[370forlife]

Re: atx YLP-013 Repair help please

Sorry for the wait. Christmas time and all. Anyways, Q7 is the 5vsb transistor. It is a C5027. The particular one used in this unit is a cheap knock-off.

http://search.digikey.com/us/en/cat/...376376?k=c5027

That should be a direct replacement.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks for the part number. I,ll get one right away.

Any experience why it blew up?

I really could use a schematic if you knew where to get one.

That would make this so easy.

[370forlife]

Re: atx YLP-013 Repair help please

Unfortunately not many manufacturer's put their schematics online or readily available. Yuelin hardly has a website, getting a schematic from them is near impossible. This is a pretty generic half bridge design common among cheap chinese manufacturers.

[Th3_uN1Qu3]

Re: atx YLP-013 Repair help please

The 5vsb primary transistor doesn't blow up often. Check the whole circuit - chances are one of the following are bad: 5vsb output capacitor(s), 5vsb rectifier diode, 2nd transistor in primary circuit (usually TO-92).

[humblesmith1]

Re: atx YLP-013 Repair help please

370forlife
Thanks for the lowdown.

I left the supply at my work and will check it out when I get back on the 2nd.

Happy New Year

[everell]

Re: atx YLP-013 Repair help please

In the mean time, here is a basic schematic and circuit explanation.

https://www.badcaps.net/forum/showth...highlight=5vsb

Good reading material, hope it helps.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks for the reading.

Very Complete.

Still a pain without a schematic but will move forward.

[humblesmith1]

Re: atx YLP-013 Repair help please

Found Q4 is also blown .
Transistor is not readable as to part number.

Do you know the number for Q4 also?

[humblesmith1]

Re: atx YLP-013 Repair help please

Note Q4 is a TO92 I think it might be a STC945 but I still can't read it except the "5", there is another STC945 in the supply.

Can I replace it with a 2N3904?

Anyone?

[Th3_uN1Qu3]

Re: atx YLP-013 Repair help please

Can I replace it with a 2N3904?

Yes, but watch the pinouts as they are different, you'll have to twist the 2N3904 around.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks for the heads up.

I did download the data sheets to see if a close enough sub but did not check pinout.

Still not sure Q4 pn is correct.

[Th3_uN1Qu3]

Re: atx YLP-013 Repair help please

It's likely to be that, you hardly see anything else.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks a lot.
I'm now waiting for the new Q7 to arrive and I'll try to repair this.
New Q7, Q4, and schottky diode.

[humblesmith1]

Re: atx YLP-013 Repair help please

I replaced Q4 & Q7 the schottkey is still good.
Checked a lot of the caps aroun that circuit and found no bad ones.


Any suggestions before I try to power this up or even a good way to power it upon the bench .

[Th3_uN1Qu3]

Re: atx YLP-013 Repair help please

Make yourself one of those: http://antiqueradio.org/dimbulb.htm

For power supplies you'll want the lightbulb to be 60 or 100W.

[humblesmith1]

Re: atx YLP-013 Repair help please

Thanks, I have a variac at work that I can use.

This is what I plan.

Jumper pin 14 to gnd.
Place 10 ohm 10 watt on + 5 vdc
Plug it into the variac.
Try to power it up.
Check all outputs.

Does this sound correct?

[Th3_uN1Qu3]

Re: atx YLP-013 Repair help please

Sounds about right. I'd still use the series lightbulb even though you have a variac - you won't be able to reach it fast enough and turn it down if something goes wrong.