[Hammarlund] SP-600-25C

[Todd, KA1KAQ]

Hey Russ -

Welcome to the SP-600 world. It's a pretty nice receiver overall, one of
the best for band cruising and many of the AM crew have used them as
station receivers.

I had severe drift problems with my first SP-600 years ago. That was the
big beef folks had with them back last century - they were 'drifty'.

Then Les Locklear who has used about every receiver ever made told me to
check the power transformer tap, as there are several input choices. Can't
remember off the top of my head what it was, but I think mine was on 115 or
117, something in that area and the next one up was maybe 125 volts? I know
my local power then was right at the limit of where it was set, so any
fluctuations like the fridge kicking in made it wander.

Moved it up to the next tap (125) and voila - rock solid stable after a
brief warm up period. Might not be an issue for you but it never hurts to
check it against what's coming out of your wall outlet.

No wires back up yet, but will look for you on 40 once the station is back
on the air.

73 -

~ Todd,  KA1KAQ/4 (now in northern VA)

On Sun, Jan 22, 2017 at 8:43 PM, <wb3fau55 at neo.rr.com> wrote:

> So, ongoing issues,  but it looks like I fixed it.  Putting the 600 on
> lime in my shack, it developed a real bad drift problem.  As I had taken
> apart  the RF deck, I found vitamin Q caps installed here.  I did not
> change these.  Just  touching  the 6C4 HF osc tube,  caused more drift.  I
> shut it down,  pulled the 6C4,  sprayed D5 in the tube socket,  sucked it
> out  with a shop vac.  I installed a new 6C4 and an IERC black tube
> shield.  Ran it  all day,  seems just fine now.  I have found  problems
> before with 6C4s.  Comments and experiences appreciated.  73s Russ.
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