----- Original Message -----
From: "Garey Barrell" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 23, 2011 5:32 PM
Subject: Re: [Drakelist] Drakelist Digest, Crystal calabrator Gone south?
My crystal was bad when received 2B with calibrator installed. Put crystal
for
for one of the bands into it to confirm that was the problem. Then, got
another
from ICM, works fine now.
73, Curt
Fred -
Most likely it's a power supply problem. If you have a DMM or VOM it
would be easy to check.
There's a diode and a couple of electrolytic caps that ONLY power the
Calibrator's Buffer and Divider stages.
D16, R158, R157, C190 and C192. It's a half-wave rectifier from the
filament supply. If you have a meter, check the DC voltage at the (+) end
of C192 which is a silver colored tubular electrolytic right by the AC
line input _WATCH FOR HIGH VOLTAGE_ .. You should measure about 15 VDC
or so there. If there is much lower or no voltage there, then it will
need replacing. It's possible that failing also damaged D16 and/or R158.
If you have voltage there, then check on the (+) end of C190, which is on
the Calibrator board, UNDER the crystal. It's a black tubular
electrolytic. and you should see about 4 VDC there.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
[email protected] wrote:
/Crystal calibrator on the Drake B line twins. Is this an easy fix or
expensive fix or is it something I could locate and fix myself? What
equipment is required to locate and repair this item. Looking at he
schematic it could be a transistor or and IC in the receiver. Any
thoughts? /
//
/73 de Fred WD8ADG/
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