Yellow caps with F logo and K vents

[arneson]

Re: Yellow caps with F logo and K vents

Wait a second, does this mean I can use the old oil filter off my truck as a capacitor?

[linuxguru]

Re: Yellow caps with F logo and K vents

Good catch - I thought they were low-voltage Sanyo (from the K-vent) and never suspected them. These Fujitsu 4v Polymers are very widely used by Intel and others for Vcore filtering on P4 boards - I've seen a lot of D845GLLY, D845WN, D845PESV, etc., at the local assembler/repair shop that use this capacitor and have startup and random reboot issues.

I think I'll advise replacement with the widely available Rubycon YXG 1000/6.3v and see what happens.

Any idea if the failure occurs because of incorrect polarity? I can't imagine that Intel would make that error on production boards, but stranger things have happened.

[willawake]

Re: Yellow caps with F logo and K vents

Any idea if the failure occurs because of incorrect polarity?

no i would not expect that. like said earlier in the thread moisture in the caps is the issue. it is a manufacturing problem.

having seen where they are usually in the board i would substitute rubycon ZL at the least. oscon or rubycon MBZ would be nice. ZL is easily available.

[darklock]

Re: Yellow caps with F logo and K vents

Wouldn't it be better to just replace these Fujitsu RE's with the same uf rating and as close voltage as possible?

The reason I ask is I have an MSI 6340 ver 1 which had its 2700uf 6.3v caps replaced with Nichicon PJ. It also has four of these Fujitsu RE caps (2 - 4v560uf & 2 - 4v820uf)

The history of the board is not known. I received the board which showed obvious signs that someone did not have the soldering skills to properly solder the 2700uf 6.3v caps...cold solder joints. The board would not even POST.

I corrected the cold solder joints, and then flashed the latest version of the bios using the hotflash method (flashed the bios chip in another board). Then the board POST'd once for about 5 seconds. Then it shut itself down, and I haven't been able to get it to POST again.

Upon reading this thread, I replaced the 4 RE's with Nichicon HE 1000uf 10v, but still it does not work. (That's all I had)

Any suggestions? Can't seem to find 560uf 6.3v in either Nichicon HE or PW series.

[willawake]

Re: Yellow caps with F logo and K vents

if you look at the intel board in the first post of this thread it has rubycon MCZ 820uf 6.3v for vcore next to the fujitsu. i have seen this to be common on good boards. i would recommend that you go higher than 560uf 6.3v for al-caps but similar for polymer.

I replaced the 4 RE's with Nichicon HE 1000uf 10v, but still it does not work.

those should be fine. you can replace the other 2 RE caps with similar to see what happens.

Wouldn't it be better to just replace these Fujitsu RE's with the same uf rating and as close voltage as possible?

matching or exceeding the design specification (i am talking about actual performance not just uf and v values) is only going to affect overclocking stability etc. as long as you dont put insanely large values on the board you should get a post.

it is possible the previous owner's soldering damaged something. needs more troubleshooting.

[darklock]

Re: Yellow caps with F logo and K vents

If I understand your reply correctly, if I can find capacitors with the same uf values (560uf & 820uf) but at a higher voltage (6.3v) it would be OK since I am not into overclocking? Looks like I will be able to source the 820uf from www.mouser.com (Nichicon HE 820uf 6.3v) and the 560uf from www.digikey.com (Panasonc FC 560uf 6.3v)
Thanks in advance

[kc8adu]

Re: Yellow caps with F logo and K vents

if you replace polymers with aluminuns double the capacitance.
the post problem is not likely related to these caps.
p.o must have damaged it or the old caps did.

[darklock]

Re: Yellow caps with F logo and K vents

Hello, I got a chance to work on this board once again. I replaced the four 2700uF Nich PJs with 3300uf caps and the board works now.

Thanks to all. Now to work on the other motherboards that I have waiting....