[Hammarlund] HQ-180 service bulletins and recommended mods

[Al Parker]

Hi Jeff,
	Doing the filament mod to the osc. & mixer tubes will greatly reduce 
drift on turn-on.  I've done that on several -170's & -180's.
	The audio ckt on these rcvrs has been the subject of lots of 
discussion.  It's meant for communication quality.  But if it's really 
cruddy sounding (technical term, there), it's most likely an issue with 
the IF alignment.  IIRC the later manuals have a mistake in the 
procedure.  Somewhere I've got some pages marked, "use this for IF 
alignment", I'll search them up for you.
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 5/23/2016 10:19 PM, Jeff wrote:
> Hi All -
>
> Just found a good HQ-180, and have it on the bench for its initial
> walk-through.  The BAMA site has the manual for this particular one in
> the "issue3" sub directory -- it looks somewhat different than the other
> 180s I've seen.  I would say it's probably an older one, but I don't
> know for sure.  The serial number is 631.
>
> Previous owner put a toggle switch on the back that seems to control the
> AC line. I haven't figured out why yet -- as it took me a minute or two
> to figure out how to turn it on (it has a clock...  my other ones don't).
>
> I plan on pairing it with the HX-500.  Here's the question to you
> Hammarlund experts: any mods that ought to be done?  I've read that
> people "convert them to the HQ-180A," but this seems more involved than
> just putting some diodes in and upping the B+ dropping resistor from 2K
> to 3K.
>
> This one is pretty badly out of alignment, but the filter caps seem
> good. After replacing a few tubes, it hears signals, but audio is poor
> -- no recapping yet.  It also doesn't appear to have the secondary
> filament transformer that lights the oscillator and mixer full time, so
> I expect a bit of drift.  Can anyone offer any insight on this
> particular edition of the 180?
>
> Thanks!
>
> Jeff
> WB3JIH
>
> ______________________________________________________________
> Hammarlund mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hammarlund at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>