Asrock k7s8x r3.0, agp regulator?

[pippolippi]

Hi, browsing this forum it doesn't seem that asrock is normally in the "badcaps" category, however I have one bulged capacitor (1000uF, 6.3V) close to the agp slot.
The symptoms: upon power up the bios beeps 8 times (repeatedly), the code is for "faulty or missing video memory" (there was a similar case in this forum but I cannot find it right now). Of course it's not the video memory (tried with 3 different cards).
It's not the power supply (tried with two more).
If I wait 5-10 minutes and reset the computer it will work with no problem or instability (at least it has been doing so for the last 3 weeks).
Note that I don't use the agp slot (in fact I have an old pci video card just to let it boot, but there's no monitor connected, this is a vdr machine that uses a dxr3 card as a tv output ).

Do you think that:

1. is this possibly an agp voltage regulator?
2. if yes, the fact that I don't use the agp slot is the possible cause of the faulty capacitor or is it just a bad capacitor?
3. will it be enough to replace just that capacitor (if I find a suitable low esr one)? (I can scavenge one 1000uF 16v marked as KME, maybe it's a Chemi-Con?)

[gonzo0815]

Re: Asrock k7s8x r3.0, agp regulator?

Yes, normaly Asrock uses good caps, at least on the criticall sections.
Any way, the problem on your models is not that unkommon. Look at the picture i provided, the red caps are probably causing your problems. This is caused probably by the high heat produced by those mosfet transistors. They provide voltage for AGP, RAM and the chipset.
I suggest replace them with low esr high temp long endurance type (e.g. Panasonic FC, Rubycon YXG, KZE, may be MCZ, MBZ, FM etc). Voltage is all abouth 5v or the coresponding lower voltage needed by the supplied section.
A higher uF rating would not hurt at all, as those are only very simple (e.g. linear ) vrms, there is no impact to expect. But i would not go lower. Higer voltage is fine too, but no benefit. Additionally i would add the mising cap, where i marked the sikscreen red.

[gonzo0815]

Re: Asrock k7s8x r3.0, agp regulator?

I forget to mention: the yello marked ones could changfed too, if they are not KZE. This will improve memory voltage, but it is not neccesary.

[pippolippi]

Re: Asrock k7s8x r3.0, agp regulator?

In my board the only bulged capacitor is the one at the left of the "missing" one in your picture. The others seem fine.

[gonzo0815]

Re: Asrock k7s8x r3.0, agp regulator?

Yes i assumed that already, but at that high temp all marked ones degrade, the cap are bad far earlier. The bulging is only the last step in the degrading prozess if ever.
All marked caps are probably prone to get bad, those near the AGP probably not or later, as you don`t use the AGP port. I recomend to reoplace the bulging one, and if you have another one the missing too.

[pippolippi]

Re: Asrock k7s8x r3.0, agp regulator?

If these regulators are linear, is it really necessary to use low esr capacitors? (since I don't know if I can find low esr capacitors around here)

[gonzo0815]

Re: Asrock k7s8x r3.0, agp regulator?

Hm may be not, as there is probably no ripple current wich would harm the cap, but any way i would rather use them. As digital chips are known to generate fast transient currents, the usage of normal cap would degrade the transient respons and increase the voltage drop significantly. If this hurts anything i absolutely don`t know.

[pippolippi]

Re: Asrock k7s8x r3.0, agp regulator?

I finally changed the capacitor. I couldn't find a low esr one so I used a normal one. Since it was a single capacitor, I disregarded everything in the faq: I just cut the old capacitor and soldered the new one on the old capacitor leads, without even removing the motherboard from the case, with an 11W soldering iron that barely melt the solder.
I'm not particularly proud of this hack job and, folks, don't try this at home , but....it works . Let's see for how long.

[gonzo0815]

Re: Asrock k7s8x r3.0, agp regulator?

Never mind the the hack job, as long as it is your rig and you know what your doing there should be no problem. I am shure, that most people here are conducting similar things sometimes if theyr to lazy or just need a quick fix. However, if you once feel to do it right, i suggest to obtain some good caps, e.g. Panasonic FM ones from RS-components. It depends where you are living, but either TC (USA only) or may be BigPope can provide you somne more decent caps.