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Old DX-160 - basic alignment and recapping (if necessary)



 
 
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  #1  
Old February 17th 05, 11:53 PM
Brian Hill
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Default Old DX-160 - basic alignment and recapping (if necessary)


"bpnjensen" wrote in message
oups.com...
Folks - I have an old DX-160 in decent shape with plenty of sensitivity
(except on AM, but I think I can remedy that) and fair selectivity. It
gets its share of IM junk, but this is the big city after all, so what
the heck...it's still a fun radio, even if its frequency is off a bit.

Anyone have a fair idea about the typical cost for alignment and
recapping of this beastie? I am willing to hire it out for a fair
price...

Thanks,
Bruce Jensen


Why don't you give it a shot Bruce?

B.H.


  #2  
Old February 18th 05, 12:04 AM
bpnjensen
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Why don't you give it a shot Bruce?

B.H.

I'd love to - but, frankly, I'm a dunce when it comes to things
mechanical or electrical! I've ruined a lot more stuff than I've
repaired, and a lot more than I care to mention. I'm not very
technically dextrous, even when my understanding is intact.

Bruce "Allthumbs" Jensen

  #3  
Old February 18th 05, 12:25 AM
Brian Hill
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"bpnjensen" wrote in message
oups.com...
Why don't you give it a shot Bruce?


B.H.

I'd love to - but, frankly, I'm a dunce when it comes to things
mechanical or electrical! I've ruined a lot more stuff than I've
repaired, and a lot more than I care to mention. I'm not very
technically dextrous, even when my understanding is intact.

Bruce "Allthumbs" Jensen


Well like Dirty Harry says " A man has to know his limitations". I wouldn't
shoot to much$s into it. By the time you pay to ship it twice and get it all
checked out and fixed your gonna probably have what the radio is worth
wraped up in it or more unless you can find some nice old fella close by?


--
73 and good DXing.
Brian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A lot of radios and 100' of rusty wire!
Zumbrota, Southern MN
Brian's Radio Universe
http://webpages.charter.net/brianhill/

EMAIL-
(Hide the $100 to reply!)


  #4  
Old February 18th 05, 06:49 AM
[email protected]
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Recapping? My old DX 160 is still playing away nicely. I bought it
new around 1976 and haven't noticed its performance is degrading.
I am not a tech so I can't say for sure but I don't think that the
caps in this radio are the kind that need replacing. They still look
nice and shiny unlike the big waxy cardboard ones in the old
Hallicrafters rig.
Experiment awhile with the fine tuning and main tuning. You will
reach a point where one or the other will show the correct freq. for
the band you are on. Note the "log " numbers on a piece of paper and
you should be able to get pretty darn close to a freq. when you want
to. If you have a digital radio you can use that to help point the
way.
Enjoy the radio. They are a lot of fun. I don't use it as my
main radio but enjoy dragging it out and using it from time to time. I
have been using it lately to listen to some 120 meter ham ragchews and
setting the BFO pitch to certain levels can overcome some local noise.
It is a bit like a poor man's passband tuning.
Regard, Bob

  #5  
Old February 18th 05, 04:43 PM
bpnjensen
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Recapping? My old DX 160 is still playing away nicely. I bought it
new around 1976 and haven't noticed its performance is degrading.

The reason I mention this is because my radio has a pretty good hum to
it on certain freqs; maybe that's not a symptom of what I think it is
(I know that a certian dimmer switch we have inserts a pretty good hum,
too, unless it is turned all the way on). If I could talk to someone
with some firsthand practical knowledge, I might be able to sort it
(maybe even here). I do know that the thing needs alignment (no doubt
I can get to and identify a frequency when I want to - I'd just like
everything to be working right).

I like the radio - it's fun to play with when I'm not after any special
weak station. If I decide to use it for this, I may add a frequency
counter.

Bruce Jensen

  #6  
Old February 18th 05, 05:11 PM
[email protected]
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I
have been using it lately to listen to some 120 meter ham ragchews ...

Uh-oh....Bunch of sick birds....:/ You probably mean 160 meters..."1.8-
2.0mhz"
Ain't no ham band at 120m....I think thats a tropical SW, and maybe
some
aircraft sprinkled in various places around that part of the
spectrum...
MK

  #7  
Old February 19th 05, 06:15 PM
Frank Dresser
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"bpnjensen" wrote in message
oups.com...


I'd love to - but, frankly, I'm a dunce when it comes to things
mechanical or electrical! I've ruined a lot more stuff than I've
repaired, and a lot more than I care to mention. I'm not very
technically dextrous, even when my understanding is intact.

Bruce "Allthumbs" Jensen


Weren't you experimenting with crystal radios a year or two ago? Generally,
repair is easier than homebrew.

Nearly all single conversion superhets align using the same simple
procedures. I think the DX-160 service manual is online, and the ARRL
handbooks have some good straightforward alignment instructions.

You can even do excellent alignments without a signal generator, if you have
digital readout receiver to read the radio's local oscillator frequency.

However, the radio may be aligned about as well as it can be. Generally,
the dial readout is exactly correct at two or three points on the dial, at
best. There are usually areas in which the dial readout doesn't perfectly
track with the received frequency probably because the tuning capacitor/
coils don't exactly match the prototype they developed the original dial
from.

Anyway, if you want to give it a try, I'm sure you can get some help here.

Frank Dresser


  #8  
Old February 22nd 05, 04:43 PM
bpnjensen
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Weren't you experimenting with crystal radios a year or two ago?
Generally,
repair is easier than homebrew.


Yes, but a crystal radio is far less involed than something you plug
in! :-)

Nearly all single conversion superhets align using the same simple
procedures. I think the DX-160 service manual is online, and the ARRL


handbooks have some good straightforward alignment instructions.


You can even do excellent alignments without a signal generator, if

you have
digital readout receiver to read the radio's local oscillator

frequency.

However, the radio may be aligned about as well as it can be.

Generally,
the dial readout is exactly correct at two or three points on the

dial, at
best. There are usually areas in which the dial readout doesn't

perfectly
track with the received frequency probably because the tuning

capacitor/
coils don't exactly match the prototype they developed the original

dial
from.


Anyway, if you want to give it a try, I'm sure you can get some help

here.

Frank Dresser


THEN...

looking at the schematic, it's got a ceramic/xtal/mechanical(?)

filter
for the first IF, so you can't really screw up the tracking by shifting

the IF like you could with an all LC tuned IF.

What I'd look for first is to see if the dial pointers haven't shifted
on the cord(s).

Mark Zenier Washington State resident

Mark and Frank - the frequency aligns correctly near the lower end of
each band - for example, on the 4-12 MHz band, WWV shows up at
virtually dead-on 5 MHz. At the upper end of the band, however, WWV is
off by *about* .6 MHz from 10 MHZ (depending on what the radio ate for
breakfast), and things are a bit worse on signals near 12 MHz. The
same is proportionally true for each of the other bands.

The bandspread dial, when used, is off by varying degrees from one end
to the other, ranging from nil to about 15 or 20 khz.

I have some instructions for fine tuning these ranges using the
band-specific coils within, but thus far I simply haven't had the nerve
to touch them. Someday I may, but I am content for now to be primarily
a listener rather than a tinkerer.

Bruce Jensen

  #9  
Old February 23rd 05, 07:16 PM
Mark Zenier
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Default

In article .com,
bpnjensen wrote:
Mark and Frank - the frequency aligns correctly near the lower end of
each band - for example, on the 4-12 MHz band, WWV shows up at
virtually dead-on 5 MHz. At the upper end of the band, however, WWV is
off by *about* .6 MHz from 10 MHZ (depending on what the radio ate for
breakfast), and things are a bit worse on signals near 12 MHz. The
same is proportionally true for each of the other bands.


The fact that all the bands are off the same amount is a bit strange,
as (according to the schematic) the LO coil for each band has both a
coil adjustment and a trimmer capacitor.

I can think of a few things.

1) The main dial and the band spread will interact, so that the main
dial is accurate only when the bandspread is at some position.

2) Somebody realigned the radio with the bandspread at the wrong
position.

3) There's a "global" adjustment for the main or bandspread capacitors.
For a lot of radios, there were some mica compression trimmer capacitors
built into the main capacitor to adjust the top end tuning. (But this
doesn't show in the schematic so this may not exist).

The bandspread dial, when used, is off by varying degrees from one end
to the other, ranging from nil to about 15 or 20 khz.


That's pretty good, actually. There don't seem to be any adjustments
for the bandspread.

Mark Zenier Washington State resident

 




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