[SignalOne] The CX7A Lives!

[jerry]

On 2024-11-07 07:41, K5OG wrote:

> As for the TX power and low drive, check Q 3 and 4 on the RF driver 
> board.
*** Indeed.  The rig has PT3657 in those positions.  Total unobtainium.  
I couldn't even
find a data sheet.  I see in the "miscellaneous information" section of 
the Trouble Guide
that one can use 2N5641.  That's VERY good news, because those can be 
got.  They ain't cheap,
but they're not unaffordable, either.

> And have you tried switching to manual tune and is it any better?
> Contacts on the wafer switches in the tube cage may be blown out. I've
> seen it many times over the years.

*** O Woe is me!  You are so right!  There is a burnt contact on the 
first ceramic wafer - the
one closest to the front of the radio.  Nothing important....just 20M. 
:(

   How to fix?  Right now it's looking like:
* Take the whole PA cage apart.
* Remove the entire bandswitch assembly.
* Take it apart.
* Scrounge an unused contact elsewhere on the wafer.  Drill out the 
rivet, and install it in the burnt
position with a new rivet.  If a suitable rivet cannot be found, *make 
one* on my lathe.  Or maybe install
that contact with a tiny screw & nut, suitably loktite'd.

   To manage my enthusiasm, I think I'd like to get the rest of the radio 
totally working before I tackle this.

                    - Jerry, KF6VB