[R-390] [off topic] HQ-180A alignment craziness

[chacuff]

Depends on which manual you are using.  There is a mistake in the majority 
of manuals as to the settings of the front panel controls for alignment of 
the 60Khz IF.  I'll see if I can find the info...I went through this same 
issue with the HQ-170.  It does make you crazy...

Cecil
----- Original Message ----- 
From: <mlmccauley at att.net>
To: <R-390 at mailman.qth.net>
Sent: Sunday, February 17, 2013 4:35 PM
Subject: [R-390] [off topic] HQ-180A alignment craziness


>
> I'm having big trouble doing an alignment on this set, and to my thinking 
> what I see just doesn't make any sense. Any help anyone could give me 
> would be greatly appreciated.
>
> As I tell this tale, bear in mind that, as is, the set will receive 
> stations and properly demodulate AM, SSB and CW. Sensitivity is poor, but 
> the radio does basically work. Selectivity is super tight, standard 
> HQ-180A behavior.
>
> The very first step in the procedure is an initial rough alignment of the 
> 60KHz 3rd IF. You connect a voltmeter to the AM detector and a 60KHz CW 
> source to the coupling cap going to the grid of the 2nd mixer (presumably, 
> leakage though the self-oscillating mixer gets the 60KHz out the back of 
> this stage (?)). You are instructed to tweak the 60KHz IF transformers for 
> maximum negative voltage at the test point.
>
> The directions say to keep reducing the signal level as you tweak so as to 
> keep the test point from going no more negative than -5VDC. Problem is, I 
> see -.35VDC, which never changes, 60KHz injection or no, low or high 
> injection level.
>
> I've verified the generator freq at 60KHz with a counter that tests one 
> Hertz off at 10MHz against a Cesium standard. I even swapped voltmeters.
>
> I've verified the injection and test point about 47 times.
>
> Any ideas?
>
> A guess - could it be that the 2nd oscillator (395KHz), mixer, and IF 
> transformers have been jacked with *so badly* that the IF strip is tuned 
> to a totally different frequency than 60KHz? These sets are notoriously 
> super-selective, maybe my "real" 60KHz is being chopped off, totally 
> outside the bandpass of the IF strip.
>
> I'm stumped. I've aligned entire radios and had them working great in the 
> time that I've been messing with step #1 on this set.
>
> Again, thanks in advance for your help.
>
> Mike, WB5MYY
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html