[Hammarlund] Need More Help on the SP-600

[Barry Hauser]

On Fri, 31 Jan 2003 00:13:39 -0600 "Charles and Sandi Hugg"
<chashugg@earthlink.net> writes:
> I have closely looked over the modules on the 3.45-7.4  section of 
> the turrent. There is some slight wear on one of the contact pins on
the 
> module closest to the back of the receiver. I think that this is the
Osc 
> Module.
 
The ones toward the rear of the chassis are the antenna stage modules.
 
> All of the pins on all of the modules are straight and very tightly 
> locked into position. No movement at all. So I think it must be the
wear on 
> one of the pins.
 
I doubt that slight wear will do it.  However, it is possible that one of
the stationary contacts under the RF deck/strip is broken so that there's
only one rather than two "fingers".  Mostly, it will still work, but
might be a poor connection on one of the 3.45-7.4 modules.  Seems less
likely, now though, if there is only slight wear on one of the pins.
 
> I have another SP600. It is the JX26 model. Could I switch out the 
> modules on that section of the turrent to see if that cures the
problem? I 
> guess that each module is aligned while in the receiver, so another
module 
> from another receiver might not work well?
 
It should work well enough without having to adjust it to the radio -- I
think.  If it's the antenna coil, there isn't much between it and the
antenna input.  It's possible that there may be a bad solder joint n the
module, so you might want to freshen those -- being careful with the coil
lead ends.  However, I had another idea altogether.  See below.
 
 
> How does one go about getting the modules out of the turrent? I see 
> the springs, but the manual says something about a special tool.
> One more question. If I try to turn the pins, it looks like I will 
> have to remove the solder on the bottom portion of the pins next to the

> nuts. Looks like that might be rather difficult. Everyone one of the
pins look 
> like they have wires soldered on them. Any source for new pins?
 
Basically, you have to depress the little clips and slip them sideways to
unlock them.  Easier to do than describe here.  Maybe someone else can
describe a technique using a needlenose pliers and a screwdriver of the
right size.  I doubt that hardly any of us has ever seen that special
tool.  There are some sources of NOS parts out there.  Check with Fair
Radio (Phil) -- he may have some turret modules -- I do think they have
that one..   If it's just the one pin, a cheap trick is to clean it
completely and tin it with solder where the mark is (contact point) but
don't do that just yet.
 
A couple of more basic things about the turret, module and stationery
contacts:  (1) check if the module itself has any play.  Is it firmly
locked into the turret?  Does it line up straight relative to the other
modules in both directions?  Use a straightedge or something and rotate
the turret to see if it's consistent with the others front to back.  (2)
While you're at it, use a flashlight to peek through the gaps in the
turret to get a look at the stationary contacts on the bottom of the RF
strip -- any broken or mangled?  You may have done some of this already.
 
Finally, there is that other idea.  There is a small switch mounted to
the back of the turret housing.  It changes the receiver over from single
to dual conversion.  The first 3 bands run single, top three run on
double.  Band 3 (3.45-7.4) is the last in the sequence before switchover,
"on the cusp" so to speak.  That switch is operated by the turret
position.  It's just a single pole switch.  It may be dirty and need a
shot of DeOxit -- or it may be out of synch. so that it's switching in
double conversion several degrees of rotation too soon or landing on the
gap between the rotor contacts. Also make sure there's no slop on the
wafer. It may be slightly warped or the rotor contact is dirty and/or
oxidized in the spot where it lands when in the Band 3 position.  Give it
the "close eyeball" inspection while operating it.  With power on, try
tapping it with an insulated tool and see if the action is the same as if
you cocked the band change knob. 
 
Let us know what happens.  And you other listmembers -- I'm posting all
this both in the spirit of sharing info, but also to encourage rebuttal
and other ideas and opinions.  (Instead of private replies which defeat
much of the value of the reflector.)  I have not seen any other posts in
reply to Charlie's questions -- and many of you out there have much more
experience with these than I.
 
Barry

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