14 Jul
2012
14 Jul
'12
1:02 p.m.
I'm getting around to doing some work on my veneered and generated
HP5307A frequency counter. Looking at all the gold-plated PCB
goodness inside, the first thing that jumps out at me is a bulging
electrolytic. It's a 940 uF, 40V unit. Not 1000 uF, but 940. Not
50V, but 40V. I'm going to substitute a pair of 470uF, 50V units
paralleled as a substitute, but this had me wondering if anyone knows
why the strange values, particularly since +/-20 percent tolerances
are common on electrolytic caps.
I'e wondersd about this before (I may even have posted about it). I
can;'t see any electrical rason why they would use such capacitors. I've
seen a PSU board where the smoothing capacitors for the inputs to various
regulators were a mix of (I think( 5600uF and 6000uF, again +/-20% (at
least). Why theey didn't specify and ft al lthe same type is beyond me.
I hae no idea what the 1000uF capacitor in your counter is for, but I'll
guess it's i nthe PSU. I would be _very_ suprised if a 1000uF didn't work
correctly there too.
-tony