[R-1051] Troubleshooting/repairing R-1051 - advice needed

[Nick England]

Here's an update on my adventures in 6-pack land. I've always
enjoyed reading contributions to the archives when others have described
their adventures in troubleshooting and repair so here goes.

Not having extender cables or a junker 6-pack to use making some, I figured
I could at least remove the covers from some modules and poke my scope a
bit deeper into the innards. Following Tony's suggestion, I first made sure
the 1mc crystal switch motor was motorizing OK (particularly after I
noticed a small setscrew had fallen out of the 6-pack when I removed it).
Yep motor is OK and the 1mc injection freq changes OK across the 2-29  mc
range. Don't yet know where the itty-bitty setscrew came from.

So on to the 100 cps module (this seemed counterintuitive until I had read
deeper and found its contribution is mixed into the 100kc injection loop).
No signal at TP3, junk at TP5. Scope probed the 11kc signal coming into the
top board (7.1mc filter) of the 100cps module -OK. But the signal
disappeared on the other side of Q1, a simple emitter follower. Huh?
Disassembled the board to test Q1 - not just dead but the base lead was
broken (how did that happen?). Soldered in a replacement and .......It is
alive I tell you, alive!. Rcvr seems to working fine now.

I was Really Really Lucky - I could find and fix the problem without an
extender or burrowing deep into these cordwood modules. And an exact
replacement 2N706 was sitting there when I pulled out my misc transistors
parts drawer (I got lots of tubes but just a handful of them squalid state
things).

I'm sure I'll be encountering more problems and learning more as I play
with these R-1051 machines. After the URC-35, I have a couple of 1051's, a
D model, and a G model awaiting attention some day. Old radios sure are fun!

Cheers & thanks for the advice & encouragement,
Nick England K4NYW
www.navy-radio.com


> On 10/19/2014 12:28 PM, Nick England wrote:
>
>> ....
>> The rcvr had very low sensitivity. RF stages checked OK, but some test
>> points on the 6-pack weren't showing much of anything on a scope. So I dug
>> a -1051D out of the garage and swapped in a 6-pack. Voila - rcvr works
>> fine
>> now. But now I need to fix the original 6-pack.
>>
>>
>