For reference the attached photos are of the Tenma 72-10480 I got from CPC Farnell late in 2022 (
https://cpc.farnell.com/tenma/72-10480/power-supply-1ch-30v-3a-adjustable/dp/IN06822 ) which is clearly a rebadged KA3003.
I had a noisy fan issue that went away with a 25V 220uF electrolytic (poked deep into the connector, which is a bit hacky but it fits nice and tightly.)
It's clear the fan doesn't cope that well with PWM.
Oddly, with the capacitor, the fan runs faster at "full" loaded speed, which seems odd, unless the output isn't actually DC when at full speed?
Excepting the risk of it falling out (which seems minimal, plus I can see it through the vents at the side)
is it safe/okay to be using this 220uF cap like this?(If you'd like a laugh... whilst experimenting with the capacitor and fan I forgot to watch the 10R power resistor which I was only intending to misuse as a 90W heater for a few moments... I was only alerted by the magic smoke coming from the melting plastic box it was slowly sinking in to.
Cue quick transfer to emergency containment pie dish. FFS!
)
EDIT: Oh I see. It's not actually a 12V peak fan control output then but actually higher? So "full" speed isn't DC then, that'll be why the original fan still gets improvement from the cap even at full speed. Does that mean I need a 35V cap rather than 25V for more safety margin?