Fortron Bluestorm AX500 repair

[SuperDuty]

Hi guys,

My Fortron Bluestorm died last month while I was browsing on the internet...heard a few pops in there and a slight burnt smell...

A CET CEF02N7 had a leg chopped and a very small unidentifiable six pins IC burnt completey on the bottom of the PCB, I have no idea what this is. The board is fine.
If you know those PSUs, what could I replace these components with ? (I've looked at the datasheets for the CET but I don't really understand what all that means).

Thanks !

[Behemot]

Re: Fortron Bluestorm AX500 repair

Photos?

[SuperDuty]

Re: Fortron Bluestorm AX500 repair

Here's some pictures, I've found another Fortron PSU in my stock that has the same architecture so I can get a comparison :
The PSU with the components I've removed :


Here's where the CEF02N7 was lying, you can see a dark spot on the left where the leg burnt :


This is where this little 6 pin chip was soldered, thankfully the PCB is intact :


Here's the CET CEF02N7 with it's left leg chopped :


Here's the two power supplies on the left the Bluestorm, on the right an FSP250-60PNA-E (Compaq OEM IIRC), you can see they have the same design, the only difference is the EMI filter is backwards on the 250W version.
It also has the CEF02N7 in the same location.


And this is the little chip on the bottom of the 250W PSU, at the same location as the Bluestorm, you can see EA510 on it :


What is this little chip and what can I replace it with ? Same thing for the CEF02N7 ?
I could take them from the 250W PSU of course, but since it's perfectly working PSU and it's very silent, I don't really want to ruin it...

[ben7]

Re: Fortron Bluestorm AX500 repair

Can you tell us what it says on the chip in question that is on the intact psu? looks to be something like ea510, but I cant tell

[SuperDuty]

Re: Fortron Bluestorm AX500 repair

Yep, that's what I said just on top of the picture :P EA510.

I looked for datasheets for I can't find anything...

[ben7]

Re: Fortron Bluestorm AX500 repair

Yep, that's what I said just on top of the picture :P EA510.

I looked for datasheets for I can't find anything...

LOL, oh sorry, I do that a lot :P

Does it have 5 pins or 6 pins? I cant tell.

[SuperDuty]

Re: Fortron Bluestorm AX500 repair

It has six pins, they're all soldered.

[ben7]

Re: Fortron Bluestorm AX500 repair

It has six pins, they're all soldered.

Darn, I cant find anything to do with it on the web.

Worst case, you will have to do the DM311 mod. That involves some solder skill and working with high voltages. Basically, the DM311 is a low-power smps control chip. It would replace the blown parts on the primary side of the 5vsb circuit.

The CET02n7 is an N-channel mosfet.
Vdss = 700v
Rds(ON) = 6.6 ohms (!!!)
Id = 1.9A

It must have shorted because the gate pin is burnt off.

[Behemot]

Re: Fortron Bluestorm AX500 repair

I believe that my has EA511.

Can I ask you for one big favour SuperDuty?

[ben7]

Re: Fortron Bluestorm AX500 repair

I THINK I FOUND IT!

There was ONE hit on google that gave me a lead to this, a CPH6501.


Hopefully that is what we are looking for, it even says its markings start with EA... Its a package with two NPN transistors inside.

[Behemot]

Re: Fortron Bluestorm AX500 repair

Double transistor id miniature package. I don't envy you the soldering, I screwed many times bigger packages with 8 pins

[b700029]

Re: Fortron Bluestorm AX500 repair

Trace the circuit a bit and see if that part makes sense in context with the rest of it. You might've found it, but the different orientation of the markings is still doubtful.

[SuperDuty]

Re: Fortron Bluestorm AX500 repair

Great ! Thank you so much ben7 ! I'll dig in my bunch of boards to see if I can find find a similar chip.
It is indeed very very small, I've already soldered a few SMD capacitors and resistors with success, so I have a bit of training...

I believe that my has EA511.

Can I ask you for one big favour SuperDuty?

Sure, what is it ?

[Behemot]

Re: Fortron Bluestorm AX500 repair

I recapped it and it looks like compensation does not like some small caps. I need list of the small caps used, mainly the manufacturer and series, capacitance and voltage is OK. Also with their location so I know which one belongs where if that would be possible

[SuperDuty]

Re: Fortron Bluestorm AX500 repair

Ok I'll try to do that They're all Teapo and Ost though and a single very small Jamicon

Does anyone know what could have caused the failure ? Could the CEN02N7 have shorted by itself ? The capacitors all look good even though they're not great.

[Behemot]

Re: Fortron Bluestorm AX500 repair

Who knows, but if womething goes wrong on the primary, you usually see some lightning

[ben7]

Re: Fortron Bluestorm AX500 repair

Ok I'll try to do that They're all Teapo and Ost though and a single very small Jamicon

Does anyone know what could have caused the failure ? Could the CEN02N7 have shorted by itself ? The capacitors all look good even though they're not great.

Its hard to tell, some component might have gotten overheated. But you will have to get some parts (just in case something is still fried) to fix it, and see if anything else is wrong.