[Amps] 30L-1 filter caps

Wed Dec 13 21:18:19 EST 2006

I have spent a lot of time in researching 30L-1 power supply options.  The
one step solution is to use the single board (combines diodes and filter
caps) from Wn4i, Yves (Steve) Pautard, 5833 Dryden rd, West Palm Beach,
Florida 33415, 561-689-8819.  They sell for about $150 and are super
quality.  My 30L-1 that has Yves' board coasts along at 2000v and bearly
nudges down when fully loaded up.  I replaced the 811a with 572B and I can
easily drive this amp to 800-850w but I run it cooler at 600-650w.  Only
problem with Yves board is that it is "destructive" to the original
schematic and mechanical design where you have to clip and resolder about 7
wires and some of the last ones are a very tight fit and challenging (at
least for me the beginner).

On another (late serial #) 30L-1 that I own someone had replaced the filter
caps with small sized (2" X 0.75") (100uf, 450v) Xircons and although
EVERYONE on this reflector and the Collins Reflector told me PHYSICAL size
does not matter BUT I beg to disagree.  I think the size makes a differencE
once these puppies are heated up and I could never find any cap replacements
rated for more than 85C and the inside of the 30L-1 with its puny fan can
boil water (100C).  After extensive searches the only good sized caps in the
75uf-200uf range were computer grade snap or screw-in which just don't adapt
easily to the Collins cap board.  I finally found the near exact replacement
at RF Parts (WWW.RFPARTS.COM) where they SELL 3"x1" 100uf 450V computer
grade axials made by Mallory (TC807).  All the 100uf 450V caps sold by
mMouser and Digikey, etc were the same small size 85C as the Xircons.

If you need to replace your diode board, K1ROD (K1ROD at arrl.net) makes an
exact replacement board, fully populated, even with the hard to find 1 ohm
resistor, and this is an easy replacement though not original if you are a
collector.

If your diode board is otherwise in good shape and of later design - I would
suggest replacing the bad diode and replacing the filter caps only.  This is
the least expensive and fastest solution (caps= $13.00 x 6) and will give
you the same results as Yves board but will keep everything original.  One
other thing to try that I have not done yet - is to increase the filter caps
to 220uf 450V.  I visited Yves shack about a month ago and that is what he
is using in his latest boards.  These are Rubicon made in China but very
high grade and he believes that the SSB peaks are much fuller with a slower
discharge of these caps.  He estimates how well the power supply is working
by measuring the time it takes when power is switched off to go from 2000DCV
to 1000DCV.  He believes it should be at least 3-5 seconds.

Hopes this helps.

73 Jerry
K1JOS

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]On
Behalf Of amps-request at contesting.com
Sent: Wednesday, December 13, 2006 12:00 PM
To: amps at contesting.com
Subject: Amps Digest, Vol 48, Issue 15

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Today's Topics:

   1. A quiz... (EC1CT Fernando)
   2. 30L-1 filter caps (Sam Effinger)

----------------------------------------------------------------------

Message: 1
Date: Wed, 13 Dec 2006 17:33:48 +0100
From: "EC1CT Fernando" <ec1cwg at dxhunters.com>
Subject: [Amps] A quiz...
To: "amplificadores list" <amps at contesting.com>
Message-ID: <021101c71ed4$92933750$24c33c0a at winxp8c9373cae>
Content-Type: text/plain;	charset="iso-8859-1"

Hello all there,
I?m in the process of buying an used PA for my second QTH and I got 2 offers
so far:

- A Kenwood TL922 in good conditions
- A Dentron MLA-2500B fully refurbished (new bleeded resistors, rebuilt PS,
10 meter mod and a few more features)

As I haven?t used any of them just would like to know your opinions. What?s
better and why..Pros and Cons. Thanks a lot in advance!. 73s.
EC1CT Fernando
E-mail: ec1ct at ure.es

------------------------------

Message: 2
Date: Wed, 13 Dec 2006 10:33:12 -0600
From: "Sam Effinger" <k9sd at ezl.com>
Subject: [Amps] 30L-1 filter caps
To: <amps at contesting.com>
Message-ID: <004e01c71ed4$6a3affe0$0100a8c0 at P4>
Content-Type: text/plain;	charset="iso-8859-1"

I have a 30L-1 that I have almost nothing invested in ...one of the filter
caps is bad and one of the diodes is shorted..

My question is

----   Should I buy the board with the filter caps and diodes already
installed ? Who sells the best board ??

----   Should I buy the caps from Surplus Sales of Nebraska and use my own
diodes ?

----  Maybe look in Mouser to see is they have the caps..will replace all
caps and diodes

------  buy the keying mod from Harbauh for $25  to get rid of the -170
volts on the keying line

any other mods??

Thanks for taking the time to read this and for any reply's

Life is good..

Sam  K9SD

------------------------------

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