[Drake] TR7 R7 NB Dummy Board

[Garey Barrell]

John -

There are three different NB boards.  Version 1 and Version 2 (NB-7) are 
both for the TR-7.  Version 3 (NB-7A) is like Version 2, with the 
addition of a crystal filter, and is the one for the R-7.

Version 2  OR  Version 3 will work in the R-7, and the Version 2 board 
has space for the crystal and associated capacitors.  You can tell the 
Version 2 board by a coaxial jumper in the lower right corner over a 
"blank" area.   I modified one a year or so ago with parts I got from 
John Kriner.  I don't know if he has more or not.  It takes a crystal, a 
couple of slug tuned coils and four dipped mica caps.

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>



John Chesley wrote:
> Thanks, Garey. I have a TR7 NB that I would like to modify for use in my R7
> and I heard that I can do this by changing some parts but don't know the
> details.  The TR7 that the NB would come out of will need the dummy board of
> course but I keep this one as a spare unit so having the NB in the spare tr7
> is not critical.
>
> -----Original Message-----
> From: drake-bounces at mailman.qth.net [mailto:drake-bounces at mailman.qth.net]
> On Behalf Of Garey Barrell
> Sent: Friday, November 28, 2008 10:23 AM
> To: Drake
> Subject: Re: [Drake] TR7 R7 NB Dummy Board
>
> John -
>
> I don't have an extra board, but the difference between the boards is 
> that the TR-7 version has diode switches to handle the "transmit" 
> direction signals.  The R-7 board doesn't need these. 
>
> The TR-7 board has two PIN diodes, 4 RFCs and several passive Rs & Cs.  
> The R-7 board has only a single PC trace from a connector pin to a coax 
> receptacle near the top of the board.
>
> 73, Garey - K4OAH
> Glen Allen, VA
>
> Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
> <www.k4oah.com>
>
>
>
> John Chesley wrote:
>   
>> Hi,
>>
>>  
>>
>> Does anyone have a NB Dummy board for a TR7 they can spare?  Also, can 
>> anyone tell me what the differences are between the NB dummy board in 
>> the TR7 and the NB dummy board in the R7?  Thanks for any advice.
>>
>>  
>>
>> John, AK3Z
>>
>>