----- Original Message -----
From: "Garey Barrell" <[email protected]>
To: "Drakelist" <[email protected]>
Sent: Thursday, March 11, 2010 1:31 PM
Subject: Re: [Drakelist] receiver xformer
Richard Knoppow wrote:
----- Original Message ----- From: "Garey Barrell"
<[email protected]>
To: "Drakelist" <[email protected]>
Sent: Thursday, March 11, 2010 11:12 AM
Subject: Re: [Drakelist] receiver xformer
Geoff -
True! Fortunately, our Drake gear has dual primary
transformers, so just a matter of moving a few wires or
even just moving a switch!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Gary, the problem is not with the voltage but the
frequency. At 50hz the inductance drops and a larger core
is needed, otherwise the transformer looses efficiency
and will run very hot.
Another reason transformers may run hot is from very
distorted waveforms on the power line. At least in the US
this is more often the case than not. Looking at the
power line waveform with a good scope may discover all
sorts of things.
I've been running my R4 B all day lately and will
check the transformer later.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
OK... My R-4B has been on all morning (about seven
hours). It sits under an open-backed shelf that is 2.5"
above it. The transformer measures 51.7 degrees Celsius,
well within "normal" temperature for electronic equipment.
This receiver DOES have a new "hayseedhamfest"
electrolytic in it, which would probably be the most
likely "fault" to cause increased transformer temperature.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Mine is quite a bit hotter, around 135F (57C) measured
with an electronic thermometer. The sensor of the
thermometer was held against the top of the core until the
reading stabilized. Ambient here is about 80F (27C) right
now.
I have fresh filter caps in it although I have not yet
installed the one from Hayseed.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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