2026-04-22 11:33 UTC
@lynn
Color me unimpressed with IMSAI's use of 15VDC rated capacitors (assuming those are factory spec) on a supply rail they rate for nominal 13.5VDC. I never before noticed that IMSAI did that.
Aluminum electrolytics don't need DC bias derating like ceramics, but they should still be specified with some headroom. 15V is only 11% over nominal, and line voltage can easily be vary over time by more than ±11%.
:-(
Replies (1)
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@lynn@woof.tech 2026-04-22 11:50
@brouhaha pretty sure this is all factory. It's also the PSU-C, Rev 1, the very first one they did. I think a few months in they changed a bunch of the design, including replacing the transformer to one that can be wired for many different input voltages, though the caps were all wired from the top, exposed, so a little more dangerous :)