baracoota wrote on 2024-09-12, 21:38:
The polymer option is intriguing, but I would really need my hand held in order to spec out equivalent ratings compared to the existing electrolytics as I'm not familiar with polymer qualities at all.
CPU VRM output (i.e. CPU V_core) side caps can be 2.5V or 4V or 6.3V -rated. Anywhere from half to the full capacity.
And the CPU VRM input appears to be the 5V rail, so either 6.3V or 10V caps will be fine. Can go with 16V too, if you like - it doesn't make a difference.
The board appears to use light-green cores with not many turns for the CPU VRM, so polymers will be fine. No need to reach the same capacity as the original caps, regardless if you go with polymers or not. IIRC, the light green cores are similar in specs to Micrometals -45 core mix... which is a relatively modern(ish) core type and used at higher frequencies. Really, the only boards that I know that care more about the capacity are older ECS and PCChips board with a TL494/KA7500 voltage-mode controller and single-sided VRM.
baracoota wrote on 2024-09-12, 21:38:I'll post the values of the existing caps once I dig out the board. Thanks everyone!
Also post the brand and series, along with size (diameter and height). That should make it easier to find replacements.
Karbist wrote on 2024-09-12, 22:29:
You can cut the silver heat shrink on the old cap with a hobby knife and put it on the new cap with the same size.
Haha, that's actually genius!
Even more funny if the board ever goes into the hands of a techy down the road that knows their caps - they might get mightily confused as to why "these" original caps are still not bad yet and/or why they have different style of vents.
But yes, this is probably the easiest solution I see. Just cut down the old sleeve on the black stripe (negative marking) and put it the same way over the new cap... and that's it? I imagine the sleeves of the old caps might require a bit of trimming, though, as they look pretty tall. Since ultra-low ESR caps are no longer available, the next best choice is Rubycon ZL, ZLH, and ZLK, Panasonic FR and FS, Nichicon HV and HW, and United Chemicon KZH and KZM. All of these should still be available on Digikey and Mouser (and other large electronic suppliers) last time I checked. Or, you could get polymers and re-sleeve those instead... though those would be even smaller in size.
PcBytes wrote on 2024-09-12, 16:31:
Although I'm not sure if that's an option - audio grade caps usually come in more exotic colors, though I don't know if they come in 2200-4700 ranges.
IIRC, they do. But these are typically only 85C and don't have anywhere near the low impedance and high ripple current rating. So they might end up not lasting too long.
dominusprog wrote on 2024-09-11, 19:29:
Check out the JWCO HGA series.
Yes, check them out... and move on. 🤣 🤣
Seriously, though, JWCO caps are no good.
I don't want to appear as some kind of brand loyalist... but it should be well-known by now that the only electrolytic cap brands that can be trusted are the main Japanese ones: Rubycon, Panasonic (Matsushita), United Chemicon, Nichicon, Sanyo (now Suncon).
With polymers, the game's a little different. There, even classic "bad cap" brands like CapXon can be OK. Wurth are good too, from what I've seen online so far, and available on Digikey.
As Majestik noted:
Majestik wrote:Never choose electrolytics by their looks!