[Hammarlund] 6C4 issues - progress ! (was dead on 15m HQ-170a)

[Ed Wirtz]

Hi, guys,

I've been reading the various posts concerning the HQ170A problem and I agree with you concerning the 6C4 HFO. I own both an HQ170A and an HQ180. I have had problems with the HFO in both of them off and on. In every case when I replaced the HFO with a 6C4WA the problem went away. I think for whatever reason the WA version is more suitable for use in those receivers especially when they get old like ours are. The receiver drifts less, too. 

Look for the 6C4WA tubes if you can.

Good luck and 73,

Ed, KØBKA
  ----- Original Message ----- 
  From: Rodger 
  To: Mike & Coreen Smith 
  Cc: hammarlund at mailman.qth.net 
  Sent: Wednesday, January 21, 2009 5:50 PM
  Subject: Re: [Hammarlund] 6C4 issues - progress ! (was dead on 15m HQ-170a)


  Very typical of a marginal HFO tube.  I noticed that Carl also has had experience with these problem 6C4's in the past also.  I have a number of 6c4 tubes that will work in pretty much everything but a Hammarlund HQ series receiver.

  The low 6 meter gain may be alignment or the first mixer may also be marginal.  The S meter readings on my HQ-170A correspond pretty closely to yours until I get to 6 meters where mine is still an S-4 on the scale.

  Rodger WQ9E


  Rodger WQ9E

  Mike & Coreen Smith wrote: 
    Well, this email will probably be premature, however, I am excited, so I had to post to the list.

    Last night for whatever reason , my new-to-me HQ-170a suddenly seemed to "come alive" out of nowhere.
    BAnds that were down in the mud suddenly sounded like I had engaged 40dB of amplification.

    I have been running it nightly for about a week now, since purchased.  First couple nights it was quite stinky (dust), though
    the inside of the bottom of the RX looks like new and inside where the tubes are is in quite nice shape. (no corrosion or dirt, just a bit of dust)

    I tried 15m last night after the RX 'came alive' and lo and behold, each time I tried I got a few seconds (usually) up to a minute
    of 15m signals, but then it would abrubtly poop out on me. PLOOP!

    Today, a friend @ work loaned me his Mercury 202 tube tester and gave me a brand new 6C4 tube (which tested quite good, but not FULL scale on the meter. (maybe 80-90%..)

    I popped in the good tube and now 15m is alive with Xtal Cal signals and has been for 1/2 hour...........now I have jinxed myself I know it.  After I type this email and hit <send>,. 15m will die for sure.

    I tested the old 6C4 tube and it also tests good, but a little lower. (60-70% on the scale)....

    Does it sound plausible that this was the source of my "no rx on 15m" problem or can that be? (ie: not oscillate only on a single band?)_

    The Xtal Cal signal is nearly pegged on 160m/80m and 40dB/9 on 40m.....20/15 and 10m are S7 and 6m is S1 exactly.

    Cross your fingers !

    This weekend I'll test the rest of the tubes, but in the meantime I'll leave it run a few hours a night to burn out the cobwebs before attempting to recalibrate it.

    Thanks to everyone for their help, information and comraderie (sp?)

    dit dit 
    Mike VE9AA
    Mike, Coreen & Corey Smith
    699 Rte 616 Keswick Ridge
    NB
    Canada
    E6L 1T1
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