From: "Gerry" 
Subject: RE: [drakelist] AC-4 Cap values


supply outputs down to their specified voltage levels.=20

I haven't intended to sound critical of your modification efforts here,
Carl.

Moreso, I am critical that Drake didn't put choke filtered supplies in =
this

equipment.   I would sure have liked my T-4XB/R-4B's AC-4 to have been

choke filtered.   (Guess they figured the cost of the choke, a place to =
put
it,

and also a slight change in the secondary output winding in the power

transformer secondaries would cost too much to add into the equipment

price.

=20

Anyhow, and Meanwhile, back at the Ranch (as "they" say, somewhere)

keep up the good work, and keep us posted.

=20

Bill Flowers   K5VKL  =20

   =20

_______________________

=20

On Wed, 02 Mar 2005 20:37:21 -0800 Carl Strode 
writes:
>=20
> Carl Strode  made an utterence to the=20
> drakelist gang
> ----------------------------------------------------------------------
> I have completed re-capping the AC-4.
>=20
> After looking at the actual caps installed, and comparing it to my=20
> supply of modern electrolytics, I have replaced the 40 mfd caps=20
> (shown  as 40 mfd on most schematics) with 33 mfd.
>=20
> The HV filter caps were replaced with 150 mfd 450 volt units.  ( I=20
> had a  bunch of these laying around).
>=20
> Since my original late model AC-4 had a 100 mfd cap installed at C3=20
> and  C4a, and an 80 mfd cap installed at  C4b,  I decided to  keep=20
> everything  simple and replace these with 150 mfd caps as well.  I'll =
save
all=20
> of my  82 and 100 mfd caps for some other project.
>=20
> The 150 mfd caps I have are circuit board mount types, with both=20
> leads  on one end.  This made installation above decks a snap.  I =
removed=20
> the  old caps, and then reamed out one of the holes used for the old =
cap=20
> ____________                   __________________
________________

 When I was finished, there was essentially no ripple at all!  only=20
> about a tenth of a volt on the 650 and the 250 volt, and about =
0.2volts on

> the bias supply.  Oh yes, as usual nowadays, the 650 is really closer =
to=20
> 700, and the  250  is about  290.  When the power supply is switched=20
> on, it thunks a bit harder than it used to, due to the lack of leaky=20
> caps and the increased cap values.  The supply is much stiffer than=20
> before. Very little sag and absolutely no detectable hum.
>=20
> I guess this demonstrates that with brute force, we don't need no=20
> steenkin regulators!
> > =
----------------------------------------------------------------------
> On Behalf of Carl Strode 
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>=20
>=20

=20


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