[Collins] 30L-1 Problem

[Wn4i]

Hello Ken .....I forgot to tell you the price for my kit is up to $135.00 by 
now

73
Yves Wn4i       30 years for Motorola  Two-Way Radios
Yves Pautard
5833 Dryden rd.
West Palm Beach
Florida 33415.....561-689-8819



----- Original Message ----- 
From: "Ken Plesser" <kenplesser at alltel.net>
To: <collins at mailman.qth.net>
Sent: Sunday, June 25, 2006 12:01 PM
Subject: [Collins] 30L-1 Problem


>
>
> Perhaps someone can help me with two 30L-1 problems (they may be related)
>
>
>
> Problem #1 facts:
>
> Input voltage: 241 VAC (4.8% over 230 VAC nominal)
>
> Plate voltage (no load): 1920 VDC (6.7% over 1800 VDC nominal)
>
> Plate voltage (full load):1750 VDC (9.4% over 1600 VDC nominal)
>
> No reports of hum on my signal.
>
> Question: Why is the plate voltage so much higher than can be attributed 
> to high input voltage?
>
>
>
> Problem #2 facts:
>
> RF drive from 32S-3: 82 watts CW on 14.2 mHz
>
> Plate current of 30L-1: 430 ma (should be 600 ma)
>
> Advancing mic gain beyond 3 o'clock causes no additional plate current.
>
> DC input power to 30L-1: 1750 x 0.43 = 752 watts (should be 960 watts)
>
> RF output power from 30L-1: 380 watts
>
> Efficiency: 380/752 = 50%
>
> RF drive and output power measurements (into a 1:1 SWR dummy load) the 
> same on both 312B-4 and Palstar wattmeter.
>
> Question: Why such low plate current (hence low input/output power) and 
> low efficiency?
>
>
>
> Could it be as simple as the 811s are going "soft," hence I can't draw 
> enough plate current, hence the plate voltage rises?  Or is something more 
> subtle taking place?
>
>
>
> Any hints or suggestions will be appreciated.
>
>
>
> Thanks and 73.
>
>
>
> Ken, W3ESH
>
> Gilbert, SC
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>