[Hammarlund] HQ-180 mods

[RAY FRIESS]

I have an HQ 170 that appears to have that failing can syndrome.  I'm really sad about it because before it started, I sent it
to an expert tech who went through it, and when he sent it back he said the specs were better than the factory specs.  It worked
fantastic for a long time, all the way up through 6 meters.
Now, I'm getting static crashes, even when the volume is turned down all the way and it is in standby mode.  Only way to 
silence it is to let it warm up for hours, and sometimes even that doesnt do it.
Sometimes I turn it on and it's just fine.
I'm told the likely culprit is those caps that shunt the cans, and yes, it is a real pain to take the cans out, and take the caps
off and replace them.  And, that full alignment will be needed if you attempt it and succeed.    In this case, it is a real
shame because this radio I have is in otherwise pristine condition physically.    And, it still has great sensitivity and would
be a real pleasure to use on an everyday basis if it wasn't for the crashes.  It also has some panel sensitivity that comes
with the crashes in that you get microphonics if you tap the front panel during the crashes.
Someone suggested that perhaps it wasnt the can syndrome, but maybe cleaning all the tube sockets and tube pins
might clear it up. I should be so hopeful, I guess HI HI.    It was also suggested that perhaps I have a bad tube.   Havent tried swapping because the tech went through all the tubes when he had it, and he said they were fine.
If I remember right, I think he said keep an eye on the voltage regulator tube... that was a bit below normal readings.



> From: ChuckOchs at hotmail.com
> To: Hammarlund at mailman.qth.net
> Date: Tue, 24 May 2016 14:19:12 +0000
> Subject: [Hammarlund] HQ-180 mods
> 
> The "most bang for the buck" mod to this radio is to replace the 5U4 rectifier with a 5V4.
> 
> The 5V4 has enough current pass ability for this radio, and will provide a delayed application of B+, something always desirable in these old sets.
> 
> Not worth the trouble to try and make this into a 180-A. They really don't drift all that much with a good local oscillator tube--certainly no more than other tube sets.
> 
> I have a 180 that I have had for over 20 years, and use as my "bedside" radio. Still has the 5V4 that I installed when I first got the thing.
> 
> Most of the capacitors in this radio are of the ceramic type and, as a rule, do not fail. If the electrolytic is good, they don't need to be recapped.
> 
> Make sure you clean the contacts on the band selector switch, as well as all of the pins on those miniature tubes. My set was as dead as the proverbial door-nail when I first turned it on. Attention paid to all those mechanical connections made a world of difference.
> 
> The worst feature of these sets is the type of RF / IF transformers that they used. Not unique to Hammarlund, nearly all of the manufacturers of the period used these because they were smaller and cheaper than the designs used in earlier radios. Today, these are failing at an increasing rate. No replacements are available,  and repairing them is a PITA best left to an expert.
> 
> Full alignment will be required after these details are attended to.
> 
> 
> Chuck
> 
> N1LNH
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