Bob -
That is backwards... The second terminal from the LEFT is RCVR K, and
the third terminal is XMIT K. Recheck. You said the receiver was
working, which means RCVR K was grounded with the relay de-energized.
These lines are called RCVR CATH and XMIT CATH in the TR-3. This is
analogous to "cathode keying" a transmitter, I.e., stages are disabled
by lifting their cathodes from ground. The first step is be check and
be sure that all the schematic points marked XMIT CATH _ARE_ in fact
grounded when the relay is depressed manually with NO power to the unit.
First, do you have the correct schematic for your unit? There were at
least two. What is the s/n of yours?
The OUTPUT terminal will be grounded, as there is a "safety" RF choke to
ground.
The "armature" is the "arm" that moves back and forth. The contacts
are designated "N.O." (Normally Open), meaning with no coil power
applied this contact is open, or "N.C." (Normally Closed), meaning a
contact that is "made" with no coil power.
This case says that the RCVR K contact is N.C., meaning it is closed
with no coil power, and the XMIT K contact is N.O., as it is open with
no coil power. Since the arm is grounded, RCVR K is grounded with no
coil power and the XMIT K is grounded when there is coil power.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
AD5VJ Bob wrote:
The Rcvr K is grounded only when I push down the contacts to the relay. This
also then opens the XMIT K is that normal otherwise it
is grounded?
Bob AD5VJ
-----Original Message-----
From: Garey Barrell [mailto:k4...@mindspring.com]
Sent: Sunday, January 10, 2010 9:22 PM
To: AD5VJ Bob
Subject: Re: [Drakelist] TR-3
Possibly. Some wire around it when they can't find a
replacement easily. It is in series with the receive antenna
lead, so should not affect your transmit capability.
Main thing is to check the Rcvr K and Xmtr K lines. The
armature for them is "common" and should be grounded.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs<www.k4oah.com>
AD5VJ Bob wrote:
Hi Garey
The bulb you are showing is not there. Could that be a problem?
Bob AD5VJ
-----Original Message-----
From: Garey Barrell [mailto:k4...@mindspring.com]
Sent: Sunday, January 10, 2010 9:14 PM
To: AD5VJ Bob; Drakelist
Subject: Re: [Drakelist] TR-3
Bob -
Attached is the page from my CD with the relay contacts identified.
Should help you find what you need to check.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement
CDs<www.k4oah.com>
AD5VJ Bob wrote:
Hi Mark
Yes I can rx both usb and LSB with no problem.
The rig is supposed to switch to the sideband
appropriate for the
band which it does on all bands except for 40 meters. On 40
it goes into usb not LSB for some reason and I have to
switch it to X
in order to get the LSB signals off of 40 meters.
Does the relay only have the upper contacts. I can see
them moving
from the top after taking the top off, or do I have to take
the relay out in order to clean any at the bottom of the relay.
Bob AD5VJ
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