[Premium-Rx] Racal 6790 Collins Filter Removal

[Dan Rae]

On 7/2/2014 3:28 AM, Gordon & Lois Duff wrote:
> I have three 6790s.  I just purchased at auction an
> A24 board populated with 6 Collins mechanical filters.
> The item arrived as advertised.  However, I was
> surprised to see that the filters were soldered in.
> They look like they are going to be a bear to get out.
>
>   
>
> I don't want to swap the A24 board as mine is much
> cleaner, probably a later version, and I know it
> works.  Any suggestions on removing the filters from
> the board?
>
>   
>
>
Gordon, why would you want to?  Might it not be better to test the board 
first and see if it works?  Cleaning is easy enough, and I know of no 
significant differences in later versions of the normal GM boards.

Even with really good de-soldering tools these are difficult to remove, 
since the board is thicker than the usual PC board and there are a 
number of plated through holes on each filter that are connected to the 
ground plane with no heat relief in the art work. You would also need to 
remove the filter matching caps and install the missing sockets if you 
wanted to use the plug in crystal / LC filter versions, and then where 
would you find the sockets?

I have removed filters from RA1792 A4 boards when these were cheap and 
plentiful and once had a 6793 with a filter that had a broken pin, but I 
really don't think there's any reason to do it in your case.

73 - Dan