Aopen AK79G-Max

[Oklahoma Wolf]

For a fair amount of time now, my board hasn't been the overclocker it used to be. Now that I'm upgrading to Athlon 64, I've decided to replace the major caps on this board out of general suspicion so I can keep using the board in the other rig. Today was the first time I've been able to get the board out of the case for a close inspection of the caps on it. Though I can't afford to buy caps at the moment, I thought I would list what it does have in the above 500uf range for anyone else who may have this board and Aopen's other nForce2 boards.

Lelon RXA 10v 10mm 3300uf x3
Samsung KZE 6.3v 10mm 2200uf x7
Samsung KZE 6.3v 10mm 1500uf x4
Samsung TMZ 6.3v 8mm 1000uf x3
Samsung KZE 16v 8mm 680uf x1

The Lelons on my board appear to be doing well. No outward signs of problems. Two of the Samsung 2200's, which surround the CPU socket, look to be bulging somewhat at the base however (was hard to tell - could be dust but probably not).

I plan to order it new caps in the next month or so if I can manage it, probably going with Panasonic FC for all of them. Replacing the Lelons may be a challenge - they're close together and the only FC's that even come close are 12mm. The other caps don't look to be a problem as far as diameter goes.

Would appreciate suggestions on alternative caps for the Lelons - I'm thinking of ordering the caps from this site as well if I can't find anything at Digikey.

[linuxguru]

Re: Aopen AK79G-Max

1. Rubycon YXG/YXH 2200/6.3.
2. Nichicon VR 3300/6.3 - not low ESR, but can handle ~1A ripple current. Three in parallel makes it 3A, and this is probably on the +5v rail feeding the buck-converter(s) for Vcore, so the amplitude of the ripple voltage is not as critical as the caps sitting on Vcore. It can't be worse than the Lelons, at any rate.

[Oklahoma Wolf]

Re: Aopen AK79G-Max

Thanks for the suggestions... will look into those. The board does regulate CPU power from 5v. Just found out too I was looking at an old Digikey catalog, and am now planning Panasonic FM's

Now I just need to see if I can borrow a good soldering iron - my ancient Radio Shack 45W iron probably isn't the best for the job anymore. Maybe I should replace it while I'm ordering from Digikey anyway.

[Oklahoma Wolf]

Re: Aopen AK79G-Max

Question - I'm slowly changing my mind on the caps I was planning to use in place of the Lelons. Was going to try and fit three 3300uf 12.5mm Panasonic FM's there, but I'm getting another idea. Need someone to talk me out of it if it's too insane.

I think I can fit two 12.5mm caps in there much easier if the third is 8mm. So, I'm wondering what everyone thinks of this idea: two Panasonic FM 4700uf 12.5mm caps with a 1200uf 8mm cap in between. It would give me close to the same total capacitance, and allow me to fit them on the board better.

If not that, I'll order the Panasonic 3300's along with some extra Chemicon 2700 KY 10mm in case I can't get the Panasonics to fit well.

[linuxguru]

Re: Aopen AK79G-Max

I've done that before, but be aware that the ripple current won't divide 3-way - it will mostly be split between the 2 larger caps and a smaller fraction will divert into the smaller cap. Exactly what proportion depends on the VRM switching frequency, the waveform on the switch-side of the buck converter and the impedance of each cap (ESR + 1/jwC).

If you spec. the two larger caps to each handle about 50% of the total ripple current in the VRM, you should be OK.

[Oklahoma Wolf]

Re: Aopen AK79G-Max

Cool, thanks - will give it some more thought. Also was thinking about going 3900uf for all three as Digikey doesn't have the 3300's in stock.

[Oklahoma Wolf]

Re: Aopen AK79G-Max

Well, part 1 of my massive recap job is finished. Today, I managed to get done my Channel Well 375W and 420W PSU's, and am happily using the Aopen board again.

First up was the 375W - did everything above 470uf in there. Had to move some ground wires that were keeping the new Panasonic FM 12.5mm 3300uf cap from fitting well, but I managed ok. The other caps I used in it were Panasonic FC, another two FM, and a couple Chemicon KY 1000uf 16v (one of which was supposed to go to the 420W but I forgot and put it in here instead).

The 420W was hell on earth - it's so crammed full of parts, it was all I could do to get the old caps out. Not only that, I bought the wrong value for 5vsb so I put the old Capxon back in (was 1000uf, 6.3v, 6mm). My 45W iron choked on this unit and its dual layer board, so I fired up the borrowed 60W to finish it. But, after two hours, I had it back in the saddle again.

Next up was the Aopen, and I could kiss those people right now. What I thought were Lelons were actually Lelons, but then I took a close look at the vcore regulator caps. Not Samsung at all - Chemicon KZE. Not one bulging from the top or the base. Looked around the rest of the board, all I saw was Chemicon. You all probably heard my whoop of glee from here

I ended up replacing only 3 caps on the board - the Lelons. I have 3 Panasonic FM's there now, 3300uf 10v. Had to arrange them in a fan formation to get them to fit, but they went in just fine.

I was very glad to not have to do the rest of the board - the borrowed 60 watt iron is not grounded, I had no antistatic mat, and no wrist strap. Definitely not recommended procedure, and I was real nervous powering up the board again. Thankfully nothing went awry.

Next phase will be the Antec SL350, FIC VA-503+, and Asus P5A-B with the one dead Sanyo. Will probably wait a couple days to calm myself down for the two boards

[Oklahoma Wolf]

Re: Aopen AK79G-Max

For the interested, here's a pic of my new FM's on the board. Also visible are some of the Chemicon KZE in the shadows of my Coolermaster Aero 7+.

[PeteS in CA]

Re: Aopen AK79G-Max

Lelon

[Oklahoma Wolf]

Re: Aopen AK79G-Max

Heh - I think my board's happier now without those Lelons - seems to be running the CPU a little cooler anyway. Could be my imagination though, or the fresh thermal paste I put on the CPU. Haven't tried overclocking yet.

Feel like a bit of an idiot - was inspecting the borrowed 60 watt iron, took the handle apart, and discovered a ground terminal in there. Wish I'd taken it apart sooner. I'll make use of it for the FIC board, on which I plan to replace all the "I.Q." and "S.I." branded electrolytics. That board has never been stable since the day it was new.