Failed motherboard choke.

[Nobby]

I need some help. (others, have said it's therapy)

 

Where do I purchase another choke for my Gigabyte Z97MX Gaming5 motherboard?.

 

It has a short in the eight pin CPU power supply socket on the board. Using a multimeter on any two of the eight pins shows continuity between all.

I tracked the fault to the first choke next to the plug. Confirmed by the nose, that unmistakable aroma of overheated electronics.

The part number on it is:      1 RO

                                            L 1504           

Just spent three hours trolling pages in electronics stores, Aliexpress, Ebay, component manufacturers and nothing.

 

Thank you in advance.

[Kilrah]

-> Moved to CPUs, Motherboards, and Memory

 

It's unlikely that's the problem, the choke will show up as a short with a multimeter in normal circumstances, so if there's a short where there shouldn't be one it's something else that failed. Did you remove the heatsinks? There will likely be a burnt MOSFET under them that's the actual culprit.

[Alvin853]

The way for a choke to fail would be, if it no longer conducts, in that case you wouldn't read continuity, but open line or very high resistance. Like @Kilrahsaid, it's much more likely you have a blown high-side MOSFET or a decoupling capacitor that went short circuit. A failed part down the line could cause a choke to blow up, because it acts a little bit like a fuse, but just replacing the choke won't fix the problem, and most likely the choke is actually fine.

[Nobby]

Thanks for your replies.

I don't have much experience in diagnosing half dead motherboards.

 

I removed the heat sinks and with what little learning I have, did a multimeter check on the mosfets.

No smell and they passed the test. (maybe you can't check them properly insitu).

 

Other MB's tested show no continuity across the 4 or 8 pin CPU supply, so I understand there maybe more to it.

The question being, where do I find one? as this is my starting point.

 

 

[Alvin853]

7 hours ago, Nobby said:

they passed the test

What do you mean they passed the test? One side of the MOSFETs should be directly (through the inductor) connected to the 12V of the 8pin connector, so if the 8pin reads as short, so should the source of the high side MOSFETs. Something doesn't add up, either you're getting a wrong reading or you're measuring in the wrong spot. 

What is the resistance reading across the 8pin? One row should be all 12V connected to each other, the other row all ground connected to each other, but 12V to ground should read in the kOhm or MOhm. What is the resistance across the "burned" choke? A choke is basically just a wire, so it should read very low resistance. 

[Nobby]

Thanks all. 

Like I say, I'm new to all this repair stuff and am more the hobbiest not wanting to let go of the bone.

This YouTube video, I have used his test 

Picture of the board with failed mosfets.

Photos don't clearly show the leakage on the choke side.

 

I have not been able to find replacements with this code. 

In fact the code is alien to me, having no idea of voltage etc.

I have Emailed who I believe are the manufactures (Vishay) and am awaiting a reply.

Surely there must be a comparable items that will safely work for a replacement, though this comes back to the fact, I have no idea.

Cheers