[Hammarlund] Hammarlund HQ-170

[Al Parker]

Hi Mitch,
	Greg & Roger have hit well on the general situation.  You didn't 
mention whether the drift eventually stabilizes or not.  If it doesn't, 
there's one more possibility -- do you have a "power strip" that you are 
using to shut off the power line to the receiver?  If so, you are 
defeating the "-A's" "keep warm" feature.  I think Greg didn't mention 
it, but Roger did, it does keep 2 tubes' filaments on at all times to 
reduce drift.  The AC line cord should be plugged into a "hot at all 
times" source.
	The factory did release some notes on the 170 which can be found at 
<http://www.hammarlund.info/hq178svc.pdf>  They don't address drift 
tho'.  As Roger notes the 6C4 tube is one that doesn't always "age 
gracefully" and can give various problems such as drift.
	Another thing you can try, is to loosen and re-tighten all fasteners 
inside, particularly those at tube sockets and for terminal strips. 
They sometimes develop either looseness or corrosion which can disrupt 
the grounding which they may be relied upon to provide.
73,
	
Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 4/9/2011 12:42 AM, Mitch wrote:
> I made an error in my first post. I posted that it drifted 25hz in 3-4 minutes. I should have wrote 250hz in 3-4 minutes.
>
> Thanks
> Mitch KJ7JA
> ___________________________