[Boatanchors] Halli SX-111

[Carl]

At first guess Id say the apparent reason is realignment of that section as 
components aged. And many ham alignments were done with insufficient 
knowledge and equipment as we all know. And then stored cuz it never worked 
right again.

When was the last time you bought one that wasnt misaligned in at least one 
stage? Unless it came from a truly qualified owner.

Carl
KM1H


----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: <boatanchors at mailman.qth.net>
Cc: "Carl" <km1h at jeremy.mv.com>
Sent: Sunday, August 23, 2009 1:59 PM
Subject: Re: [Boatanchors] Halli SX-111


> Carl,
>
> My experience is indeed the 50kc IF and in the 50.5 kc IF in specifically 
> in the SX-101s.
>
> I began replacing them one at a time.  Then test for function.  I changed 
> one that was a stage bypass cap and the receiver stopped working.  I went 
> back, put the pink Tiny Chief back where it just came out of and got the 
> receive back.
>
> I'm not sure if it is inductance or resistance.  I do not have a highly 
> outfitted bench as some do.  Some things I have to either calculate or 
> best guess it.  This IS frustrating to say the least.
>
> Roy Morgan has also commented on this VERY same thing.  Where in nine 
> years of archived E-Mail?  I have no clue!
>
> It isn't an absolute thing, just something to be aware of.
>
> Bob - N0DGN
>
> Carl wrote:
>> Do you have any specific examples Bob?  The only Ive heard mentioned is 
>> in 50 kc IF switched filters and even that is highly suspect.
>>
>> I suppose one could measure the inductance and compare to the various 
>> modern film caps. Or take it a step further by breadboarding a filter and 
>> then trying various caps while watching the shape on a VNA.
>>
>> I prefer the change them all approach as I dont want to go back in later 
>> as any paper cap is guaranteed to leak sooner or later. Most likely 
>> sooner as they get subjected to heat and voltage again. Remember that 
>> many so called "fully operating" radios were stored for decades which 
>> slows down the process.  Ive noticed no change in filter curves in a 
>> SX-71 or SX-100.  My SX-115 was built with disc ceramics
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- From: "rbethman" <rbethman at comcast.net>
>> To: <boatanchors at mailman.qth.net>
>> Sent: Sunday, August 23, 2009 1:19 PM
>> Subject: Re: [Boatanchors] Halli SX-111
>>
>>
>>> Dick,
>>>
>>> Even "some" of the original REAL BBOD's need some thought given before
>>> simply replacing.
>>>
>>> It appears that they had some characteristics that made their use in
>>> bypass a little unique.  Several folks have had nothing but trouble with
>>> the complete removal of all BBODs.  I've only replaced those in my
>>> SX-101 MkIII that were in a critical circuit that would cause circuits
>>> to llet the smoke out.
>>>
>>> Other than that, There are still a lot of radios that have them from the
>>> original installation and work fine.  Sometimes I check to see what
>>> shape they are in by lifting one leg and running my C-3 capacitor tester
>>> on them.
>>>
>>> It is somewhat a darned if you do and darned if you don't.  When in the
>>> IF area, don't simply go crazy.
>>>
>>> As to the "second generation", I think you are referring to the pink
>>> ones.  They are NO different, and are original.
>>>
>>> I've got that same mixture in the HT-32 and the SX-101 MkIII.
>>>
>>> Both radios work fine.  Still!
>>>
>>> Bob - N0DGN
>>>
>