[time-nuts] Replacement A9 boards for the HP 5065A

Gerhard Hoffmann dk4xp at arcor.de
Sat Feb 24 20:34:36 EST 2018

Am 25.02.2018 um 00:45 schrieb cdelect at juno.com:
> Hi,
> I'm working to make some replacement A9 boards for the HP 5065A to the
> new style schematic.
> Will share the Gerber file when done.
> The integrator capacitor is a 1986 vintage TRW 5.0ufd 50V 10% .42"DX1.0"L
> axial.
> Of course it has an HP part number and no manufactures #.
> Any guess as to what type it is?
> Polycarbonate, polypropylene, ???????
> Just wanting to find a good modern replacement for its use. (Integrator
> with a 50ms time constant.)

50 ms integration time and 5uF+-20% does not sound like a
leakage current problem. Polypropylene seems good enough.
Teflon would be a joke. I might even go with WIMA MKS4
(Polyester) if I had them in the drawer. Dielectric absorption
is also not a problem at these impedance levels and time constants.

When I recapped the electrolytics in my 4274A RLC bridge, it was
hard to find capacitors that fit the board footprint of the old ones.
Usually I had to choose 2 or 3 times the voltage so that they would
fit the board.  But that is a luxury problem. :-)


Mouser.com  should have just as much.

regards, Gerhard

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