[R-1051] Obscure Spectrum Generator alignment question: A1L2 - 500kc input peaking

[David Wise]

>-----Original Message-----
>From: r-1051-bounces at mailman.qth.net 
>[mailto:r-1051-bounces at mailman.qth.net] On Behalf Of Dennis McLaughlin
>Sent: Monday, August 27, 2012 5:38 PM
>To: r-1051 at mailman.qth.net
>Subject: Re: [R-1051] Obscure Spectrum Generator alignment 
>question: A1L2 - 500kc input peaking
>
>Dave,
>
>Could L2 series resonate with C3 and the lump sum value of the Q1 
>trigger amplifier?  C3 looks like it is to big to do this.
>I checked mine a while ago.  I had 0.6 v p-p at A1J3 and the 
>signal was 
>OK at TP1 so I didn't try to adjust the slug. I will remember the 
>acetone trick.  Good one.  I adjusted C301 in the frequency standard 
>while the radio was fully assembled with the frequency standard cover 
>off.  If I remember right the adjustment was broad and could 
>be adjusted 
>with the standard removed from the radio.  The cable and module 
>capacitance would not detune T302 (500 khz).  Maybe L2 is the same way.
>The 10 mhz adjustment C307 in the frequency standard is quite 
>sensitive 
>and could easily be misadjusted.  I made that adjustment with 
>the radio 
>fully assembled with the frequency standard cover off.

I wondered about that, Dennis, but I'm with you; C3 is too big.
Plus Q1 is unbiased, so C3 will build up a charge and only be
loaded on the negative peaks.  To L2 it will mostly look like
C3 (10nF) and R2 (4.7K) in series; no Q to speak of.
I think that except for the "lucky" ones with the early-type
frequency standard, we can ignore L2.

Thanks for the frequency standard tips.  Mine's acceptable, but
given the happy results so far I'll probably touch it up, just
because I can.

You made me look up the frequency standard schematic, to see
which manual you're using.  You're using NAVSHIPS 0967-970-9010,
the R-1051B manual.  I compared with NAVELEX 0967-LP-970-9010
(which documents -plain late production), and the A2 multiplier/divider
boards are *completely different*.  It looks like different
engineers did them, working to the same spec.  It's great to
have a variety of resources.  Now I'm curious, which kind do
I have?  I'll report back another time.

Dave Wise
SWL in Hillsboro OR