[Boatanchors] HQ-180 Need Help

[Barry H]

Hi John & list

I am by no means an expert on these, though I have one and some experience with it.

It sounds like you've done most of the intelligent things, but this may be a dumb problem which calls for Neanderthal technology -- such as one of the most ancient tools -- a pointed stick.  I'm not kidding.

With the receiver out of the cabinet, run it until it quits.  Then tap around the chassis to see if there's any action/change.  From your description, it sounds most likely that there's some form of intermittent.  Some of these can be devilishly counterintuitive.

Two immediate possibilities come to mind ...

-- Bad solder joint.  This does not mean an obviously cold joint (dull, rough).  Shiny, good-looking joints have been known to fail internally due to long-term chemical reactions -- dissimilar metals, contamination from rosin that did not completly boil off or surface when the joint was made, etc.  They can form an intermittent, or even an unintentional component -- resistor, diode, etc.  A "skin" can form inside and alternately burn through.  Could go on and on theoretically, but the only remedy to rule it out is to freshen up the most likely joints and see what happens.  It helps if the pointed stick (tap) test localizes it, but it might not.  You may have to tip the receiver up on one side and tap on some joints under the chassis -- keep one hand in your pocket ;-)

-- Trick tube.  Even you think you might have outwitted it by swapping tubes between the 180 and the 170, there's still a chance of this.  With my HQ-180, while it was fully working on delivery, I found that some tubes were so microphonic that I could hear my own voice through the speaker if I "spoke" to the front panel.  The tubes that seem to be prone to this are the 6GH8A's, at least in my case.  I know that's not your situation, but microphonics are indicative of loose tube elements.  It's possible that when you swapped them, the bad tube held long enough to give you the conclusion that you eliminated it as a problem -- one variant of Murphy's Law.

The fact that you can "restart" the radio by turning it on and off again, also suggests a bad cap somewhere.  I don't recall if they have any tubular/paper caps.  What's the condition of the electrolytics?  Is there any hum at all?  

I wouldn't give up on this HQ-180 so soon -- and especially if it were a gift.  Also a bit premature to ship it off to someone to fix.  Sounds like (from what you've done) you should have the ability to shoot this bug.  However, you might have to temporarily reduce your IQ level to find it.  I have found this after carefully analyzing certain problems, just about giving up and then accidentally -- or out of frustration -- doing something dumb -- and getting a clue from that.

good luck & hope this helps ..
Barry





-- "John Page" <k4kwm at hotmail.com> wrote:
I picked up a very nice looking HQ180. It even worked great. Now it is deaf 
as a post. I can hear WLW on 700KC quite loud and a couple other broadcast 
stations. Nothing on band 3. A little on band 4. Band 5 and 6 sometimes. 
When a station is found it has very bad qsb.

I have done a complete alignment by the book using an HP-606A generator, HP 
freq counter, and an HP-410B vtvm. All tubes were checked and reinstalled 
one at a time. I even swapped out most of the tubes one at a time into my 
HQ-170.

Alignment on these things is complicated but not that difficult and I have 
gone through it many times.

It will work pretty good and then it will go deaf.

Sometimes, and this ought to be a clue, it wont work at all and I just click 
the onoff switch on the power strip on the bench and it comes to life. But 
so far I havent been able to find the problem.

Also all voltages and resistance measurements are as noted in the manual 
charts.

Also, for what its worth, I hooked up an Ameco nuvistor preamp and when I 
find a signal on the band, the preamp will really bring the receiver to 
life. I am talking about s2 to 3 signals going up to 40 db over s9.

I am nowhere near the tech some of you guys are but can usually get one of 
these things going.

Anybody got any suggestions? I am ready to get rid of the thing but hate to 
as it was a present from my wife.

Maybe someone on the list works on Hammarlund and would let me ship it to 
them for repair.

Thanks in advance for any help.   John

John Page K4KWM
Hollow State since 1953
(ex W8PKU,N8BLB,NA8O)




>From: "david knepper" <collinsradio at adelphia.net>
>To: <boatanchors at mailman.qth.net>
>Subject: [Boatanchors] 6AM5
>Date: Sun, 27 Nov 2005 11:45:49 -0500
>
>Need two for an Eddystone 770R receiver.
>
>Thank you
>
>Dave, W3ST
>Publisher of the Collins Journal
>Secretary to the Collins Radio Association
>www.collinsra.com - the CRA Website
>CRA Nets: 3805 Khz every Monday at 8 PM EST
>and 14255 every Saturday at 12 Noon EST
>
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>


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