Hardware Insights Forum

It'll be some time before I actually do it, but here's my plan:

The CPU VRM has three 1500µF 16V 10mm MBZs on the +12V input and a row of seven 1500µF 6.3V 8mm MBZs (with two usable blank spots at the ends of the row), along with a single 3300µF 6.3V 10mm KZG, on the output. I don't see an actual VRM for the RAM power, but the caps there are two more 1500µF 6.3V 8mm MBZs (which I'm concerned about the risk of knocking over, being tall and thin) and a single 1000µF 6.3V 8mm MBZ (which is barely over half the height; identical caps are used throughout the rest of the board). Given sufficiently low ESR, how much capacitance do you think would be enough??? The minimum safe rating for the CPU caps on this board would be 2.5V and for the RAM (DDR1), 4V.

I intend also on swapping the 100µF 10V 5mm general-purpose Teapos, along with a 22µF 16V GSC, for Panasonic NHG and GA series, respectively. I'm not too reassured about that last one even if it's under extremely little stress.

I'd say go with 470uF on the CPU VRM high side and 1500uF on the VRM low side. For the RAM, check what voltage is going through them. For the RAM, go with 680uF.

c_hegge wrote:...and 1500uF on the VRM low side.

I don't think I need 1500µF for every single cap there. Maybe just for the big one.

For the RAM, check what voltage is going through them.

I've checked which caps are for the RAM. 4V caps would be enough even with SDR (which runs at 3.3V).

Sorry, I didn't read that properly. For some reason, I was under the impression that all of the caps on the VRM low were 3300uF. 820uF should do fine for the 1500uF caps.

An update: Having been inside that PC again (in the search to solve that front-audio-cable problem; it has an identical case to the one I'm using), it is now clear that the KZG is bulging and leaking, while no other capacitor on the board shows the symptoms — proving that it was on the verge of failure all along.

I've also ultimately decided that I might as well use (fairly) low ESR (and also higher endurance) replacements for the smaller caps. I will continue to keep them as short as practical to reduce the risk of mechanical damage, which leaves me looking now at Nichicon PW series for the 100µF 10V units (as I prefer to stick to non-aqueous types for audio coupling) and TT from the same company for the 22µF 16V.

Those should do fine for the 100uF and lower caps. Last time I had to recap the Audio section on a motherboard, I used Panasonic FC. The board is still working with no audio problems.