Chemi‑Con KYB drifting up in capacitance?
Posted: November 27th, 2024, 6:38 pmWhen the APFC in my IP-P300BN7-2 failed (again!) and violently blew the 180μF 400V Chemi‑Con LXS (my replacement for the original OST SPS), I tested the secondary capacitors upon salvaging them to be on the safe side. Most (Panasonic FR, Rubycon YXJ/YXS/ZLJ) are healthy but I found that the 3300μF 6.3V KYB I used on +3.3V has risen to ≈4000μF; I went ahead and measured my 7 unused spares from the same batch, getting very much the same result on all of them.
My 2200μF 6.3V KYBs (5 spares) from the same time are a similar story, measuring consistently ≈2750μF.
My 2200μF 16V KYBs (6 spares) from the same time are still good – as are the 1500μF 16V KYB I used on +12V, and a 680μF 16V one I purchased earlier – so maybe the issue only affects 6.3V KYBs (I don't have any 10V KYBs to test), or maybe it's a matter of luck. Is it possible that Chemi-Con focused too much on operating performance at the expense of shelf life (they only claim 500 hours at 105°C for it and their other aqueous series, after all)? If it was just the 3300s I could have reasonably dismissed them as a poor batch, but the 2200 and 3300 pieces I have are clearly from different batches so that explanation doesn't convince me.
It's not just a problem with 6.3V electrolytics in general, as my 1000μF 6.3V FRs (one used on +5V and 8 spares) are all within ±10% and even three of the original green‑sleeved 4700μF 6.3V KZEs (removed from a Socket A mainboard, hence >20 years old) are well within tolerance.
Even old mainboard-grade capacitors have remained within tolerance after over a decade of storage, so it's really concerning to see this from young KYBs
Anyhow, as a precaution I'll go with other series for future purchases (definitely for the 6.3V or 10V, and also for the 16V+ unless only the KYB is in stock)…
My 2200μF 6.3V KYBs (5 spares) from the same time are a similar story, measuring consistently ≈2750μF.
My 2200μF 16V KYBs (6 spares) from the same time are still good – as are the 1500μF 16V KYB I used on +12V, and a 680μF 16V one I purchased earlier – so maybe the issue only affects 6.3V KYBs (I don't have any 10V KYBs to test), or maybe it's a matter of luck. Is it possible that Chemi-Con focused too much on operating performance at the expense of shelf life (they only claim 500 hours at 105°C for it and their other aqueous series, after all)? If it was just the 3300s I could have reasonably dismissed them as a poor batch, but the 2200 and 3300 pieces I have are clearly from different batches so that explanation doesn't convince me.
It's not just a problem with 6.3V electrolytics in general, as my 1000μF 6.3V FRs (one used on +5V and 8 spares) are all within ±10% and even three of the original green‑sleeved 4700μF 6.3V KZEs (removed from a Socket A mainboard, hence >20 years old) are well within tolerance.
Even old mainboard-grade capacitors have remained within tolerance after over a decade of storage, so it's really concerning to see this from young KYBs
Anyhow, as a precaution I'll go with other series for future purchases (definitely for the 6.3V or 10V, and also for the 16V+ unless only the KYB is in stock)…