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Today's Topics:
1. TR7 Driver Stage on PA Board Questions (J. Steven Cochrane)
2. Re: TR7 Driver Stage on PA Board Questions (Gary Poland)
3. Re: TR7 Driver Stage on PA Board Questions (J. Steven Cochrane)
4. Re: TR7 Driver Stage on PA Board Questions (Jim Shorney)
----------------------------------------------------------------------
Message: 1
Date: Fri, 21 Mar 2014 16:21:32 -0600
From: "J. Steven Cochrane" <w7...@msn.com>
To: "drakelist" <drakelist@zerobeat.net>
Subject: [Drakelist] TR7 Driver Stage on PA Board Questions
Message-ID: <bay178-ds17aaf811b3e47132b0aaffff...@phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
I have two TR7 questions:
1. There is a VERY fine wire, like fuse wire, that runs next to T2802
toroid (side closest to the final amp stage), it is broken. Could that
be why I don't have 13.6 volts going to the Driver Transistors (there
is 13.6 volts at the Test Jumper for the Bias Measurement)? The toroid
doesn't look all that good either, but neither does the one in my good
TR7.
2. Does anyone know of an easy way to replace that wire and T2802 if
necessary?
If anyone has a working PA board they would like to sell I'm
interested.
Steve
J. Steven Cochrane W7JSC
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Message: 2
Date: Sat, 22 Mar 2014 06:11:56 -0400
From: "Gary Poland" <gpola...@cinci.rr.com>
To: "J. Steven Cochrane" <w7...@msn.com>, "drakelist"
<drakelist@zerobeat.net>
Subject: Re: [Drakelist] TR7 Driver Stage on PA Board Questions
Message-ID: <07C5E19DBA084E63BCEA05DD7C3547D6@Inspiron580>
Content-Type: text/plain; charset="utf-8"
Yes it needs to be connected. It is not a fuse but a test point for
driver bias.
73, Gary
http://home.roadrunner.com/~w8pu
R-4A T4-X R-4B T4-XB R-4C T4-XC MS-4 L-4B RCS-4
2A 2B 2C 2NT 2CQ 2AS 4-LF
TR-4 TR-4C TR-4CW/RIT RV-4C MC-4
TR-7 RV-7 CW-75 MS-7
WH-7 W-4 WV-4 MN-2700 MN-4C MN-2000
UV-3 PS-3 TR-22C TR-33C AA-10 AC-10 MMK-22 TR-6
PRN1000
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Message: 3
Date: Sat, 22 Mar 2014 06:22:21 -0600
From: "J. Steven Cochrane" <w7...@msn.com>
To: "drakelist" <drakelist@zerobeat.net>
Subject: Re: [Drakelist] TR7 Driver Stage on PA Board Questions
Message-ID: <bay178-ds16550d71db93736db1c65cff...@phx.gbl>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Thanks Jim
Oh boy, yes T2302. I don't know why I said 2802, I guess that's what
happens
when your old, tired and frustrated.
I figured that's where my 13.6 volts was going by following the
schematic
but wanted to confirm it before I started dissecting T2303 to get to
T2302.
I wonder if I could put a new lead to T2302 from the bottom side of the
card? At least that way maybe I could test it and see if I have to
rewind
T2302 before removing T2303.
I'll have to study it and see how difficult this is going to be either
way.
If someone has a good PA board they want to sell me I'm ready to buy
one.
Steve w7jsc
--------------------------------------------------
From: "Jim Shorney" <jshor...@inebraska.com>
Sent: Friday, March 21, 2014 8:14 PM
To: "J. Steven Cochrane" <w7...@msn.com>; "drakelist"
<drakelist@zerobeat.net>
Subject: Re: [Drakelist] TR7 Driver Stage on PA Board Questions
I assume you are referring to T2302, there are no 28xx parts on the PA
deck. I
suspect what you are seeing is one of the lead wires from T2302, which
is
part
of the RF filtering system for the collector voltage to the drivers.
It
looks
to be bifilar wound, so yes, a break in the common lead would kill
13.6 to
both
of the drivers. It looks like to get to it you would need to remove
T2303.
Not
an easy task, but do-able. I don't have one in front of me, just
looking
at SM
pictures right now. Once you can get to it, it shouldn't be a big deal
to
either patch the broken lead or re-wind it.
73
-Jim
NU0C
On Fri, 21 Mar 2014 16:21:32 -0600, J. Steven Cochrane wrote:
I have two TR7 questions:
1. There is a VERY fine wire, like fuse wire, that runs next to T2802
toroid (side closest to the final amp stage), it is broken. Could
that be
why I don't have 13.6 volts going to the Driver Transistors (there is
13.6
volts at the Test Jumper for the Bias Measurement)? The toroid
doesn't
look all that good either, but neither does the one in my good TR7.
2. Does anyone know of an easy way to replace that wire and T2802 if
necessary?
If anyone has a working PA board they would like to sell I'm
interested.
Steve
J. Steven Cochrane W7JSC
--
Ham Radio NU0C
Lincoln, Nebraska, U.S.S.A.
TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A,
GT550A/RV550A,
HyGain 3750, IBM PS/2 - all vintage, all the time!
"Give a man a URL, and he will learn for an hour; teach him to Google,
and
he
will learn for a lifetime."
HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/
http://incolor.inetnebr.com/jshorney
http://www.nebraskaghosts.org
------------------------------
Message: 4
Date: Sat, 22 Mar 2014 08:32:12 -0500
From: "Jim Shorney" <jshor...@inebraska.com>
To: "drakelist" <drakelist@zerobeat.net>
Subject: Re: [Drakelist] TR7 Driver Stage on PA Board Questions
Message-ID: <20140322134104.95e9d283...@mail02.inebraska.com>
Content-Type: text/plain; charset="iso-8859-1"
I assume you are referring to T2302, there are no 28xx parts on the PA
deck. I
suspect what you are seeing is one of the lead wires from T2302, which
is part
of the RF filtering system for the collector voltage to the drivers. It
looks
to be bifilar wound, so yes, a break in the common lead would kill 13.6
to both
of the drivers. It looks like to get to it you would need to remove
T2303. Not
an easy task, but do-able. I don't have one in front of me, just
looking at SM
pictures right now. Once you can get to it, it shouldn't be a big deal
to
either patch the broken lead or re-wind it.
73
-Jim
NU0C
On Fri, 21 Mar 2014 16:21:32 -0600, J. Steven Cochrane wrote:
I have two TR7 questions:
1. There is a VERY fine wire, like fuse wire, that runs next to T2802
toroid (side closest to the final amp stage), it is broken. Could that
be why I don't have 13.6 volts going to the Driver Transistors (there
is 13.6 volts at the Test Jumper for the Bias Measurement)? The toroid
doesn't look all that good either, but neither does the one in my good
TR7.
2. Does anyone know of an easy way to replace that wire and T2802 if
necessary?
If anyone has a working PA board they would like to sell I'm
interested.
Steve
J. Steven Cochrane W7JSC
--
Ham Radio NU0C
Lincoln, Nebraska, U.S.S.A.
TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A,
GT550A/RV550A,
HyGain 3750, IBM PS/2 - all vintage, all the time!
"Give a man a URL, and he will learn for an hour; teach him to Google,
and he
will learn for a lifetime."
HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/
http://incolor.inetnebr.com/jshorney
http://www.nebraskaghosts.org
------------------------------
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End of Drakelist Digest, Vol 32, Issue 10
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