[Boatanchors] DX 100

[WØQFC]

Carl and the group:

Funny that you mentioned micas because I am restoring a National HFS (1943) 
and am making up a list of micas and tubulars to replace in the receiver.
Also, what would be the opinion on the ceramic type (dog bone, npo, etc.) 
caps?

Gene, WØQFC


----- Original Message ----- 
From: "jeremy-ca" <km1h at jeremy.mv.com>
To: "Jim Brannigan" <jbrannig at optonline.net>; "Kenneth D. Grimm, K4XL" 
<grimm at sbc.edu>; "Glenn Little WB4UIV" <glennmaillist at bellsouth.net>
Cc: <Boatanchors at mailman.qth.net>
Sent: Tuesday, November 06, 2007 12:13 PM
Subject: Re: [Boatanchors] DX 100


Mica capacitors seem to be reaching the end of their useful life in lots of
equipment. In the past few years Ive found bad ones in receivers,
transmitters, auto and home radios built in the 30's to 50's; even a few
60's & 70's in Heath equipment. They have all been the rectangular or
postage stamp square style. Close magnification shows cracks where the
halves are joined and most likely allowing moisture to get in.

In the past it was usually the dog bone style that became defective when
dealing with non paper or electrolytic construction.

Im also seeing a lot more resistors go up way out of tolerance.

Just more things to concern the serious restorer of boatanchors.

Carl
KM1H



----- Original Message ----- 
From: "Jim Brannigan" <jbrannig at optonline.net>
To: "Kenneth D. Grimm, K4XL" <grimm at sbc.edu>; "Glenn Little WB4UIV"
<glennmaillist at bellsouth.net>
Cc: <Boatanchors at mailman.qth.net>
Sent: Tuesday, November 06, 2007 10:01 AM
Subject: Re: [Boatanchors] DX 100


>
> I had a similar problem with a Ranger and it was the mica capacitors.
>
> Jim
>
>> Unfortunately, I've had the exact problem with a DX-100 and it was
>> caused, as Glenn suggests, by one of the mica caps in the vfo.  Too many
>> years have gone by for me to be more specific, but I remember the
>> incident well because, at the time, it was generally believed that the
>> mica caps would last forever.  That proved to not be the case!   :-)
>> Good luck in finding the offending part.
>> 73,
>> Ken, K4XL
>>
>> Glenn Little WB4UIV wrote:
>>> Sound to me to be a mica capacitor that is used to resonate 160/80
>>> meters. Some mica capacitors had a problem where a plate would come
>>> disconnected from the endplate. With temperature it would reconnect and
>>> change the capacitance.
>>>
>>> This is a guess, having not seen the DX-100 but replaced a number of
>>> mica capacitors for this problem
>>>
>>> 73
>>> Glenn
>>> WB4UIV
>>>
>>> At 08:40 AM 11/06/07, Joe Dube wrote:
>>>> I recently aquired several DX 100's  to refurb.  I have run into
>>>> several strange problems most of which I couold take care of. One
>>>> though is really confusing and I was wondering if anyone out ther has
>>>> seen this before and maybe could give me a bit of advice.  The VFO is
>>>> rock solid on 40-10 meters. On 160 and 80  is is unstable. It shifts
>>>> several cycles at odd intervals.  It can be heard when you key the vfo
>>>> by itself.  Sounds like the supply voltage is changing but  like I said
>>>> before the vfo is rock solid stable on 40 and above.  That might seem
>>>> to eliminate the supply voltage??    Would anyone out there have any
>>>> Idea what could be the problem or have a few places for me to look
>>>> without having to dismantle the VFO?  Any help would be greatly
>>>> appriciated.
>>>>
>>>> Joe K4TR
>>
>>
>> -- 
>>
>> Ken K4XL
>> k4xl at arrl.net
>>
>> *** BoatAnchor Manual Archive ***
>> On the web at http://bama.sbc.edu and http://bama.edebris.com
>> FTP site info: bama.sbc.edu login: anonymous p/w: youremailadr
>>
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