Dan
They are shown in my schematic as 1N5401 3amp 100v
73 Larry K1ZW
------------------------------
Message: 4
Date: Mon, 23 Sep 2013 11:43:18 -0700
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
To: Dan Evans <k9zf@yahoo.com>
Cc: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: Re: [TowerTalk] HD-73 Rotator issues--digital readout
Message-ID: <52408BC6.8080709@karlquist.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 9/23/2013 5:58 AM, Dan Evans wrote:
More trouble shooting found two bad diodes where the pot leads come into
the controller. I found a couple of 1N914's in the junk box and swapped
these out. Now the meter works, but is horribly inaccurate.
Yesterday I got a couple more hours to dig into it. I put the circuit
board under the magnifier so I could see it (my vision ain't what it used
to be...) and spotted a resistor that had been pretty hot. I swapped out
this 15 ohm resistor and varified all of the other resistors and diodes
checked OK. Success at last! It now appears to be working normally.
So, if you have a similar problem with your controller, check the diodes
on the pot leads and go over all of the resistors on the circuit board.
And now that I know the workings of this rotator so well, I'm thinking of
some mods. I would love to have a digital display...
73
Dan
AFAIK, there are no diodes across the pot leads; what in the world could
they possibly do? At least they are not shown on any version of the
schematic I have seen. I think what we have here is some poor clown
who got a bunch of RF on his control lines and was attempting to fix
------------------------------
End of TowerTalk Digest, Vol 129, Issue 47
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