[Kenwood] 950SDX Repair: Static in RX]

[Mike]

Yea, its a pain.
I had to cut specific traces and isolate circuit paths to find this 
particular problem.
The NTE519 is the direct crossover part for the US1090 Diodes Kenwood 
used for D14 and D15.
They can be gotten from Mouser Electronics.
Also another note...
In order to check to see if D14 and D15 are bad, at least on leg on each 
diode needs to be lifted from the circuit board.
Take Care,

Mike
WZ5Q
from Deep Down in the Dark Dismall Swamps of the Calcasieu
http://www.wz5q.net



Steve London wrote:
> That was exactly the same problem I had. I replaced both D4 and D5 
> with garden-variety switching diodes and the problem was solved. It 
> sure took a long time for me to isolate this problem. Anyone have any 
> tricks for finding microvolt-level noise sources in RF stages ?
>
> 73,
> Steve, N2IC
>
> Mike wrote:
>> Howdy Bob,
>> I have had a 950sdx here, that showed similar symptoms.
>> It turned out to be a leaky Diode (D5) on the RF Board.
>> It was leaking DC instead of blocking it and was creating a Broad 
>> Banded white noise on the Lower Bands.
>> It was on all bands but was more predominate on 160 to 20 meters.
>> This was on both the Main and Sub-receivers and could be seen on the 
>> S-meter WITHOUT an antenna connected.
>> For your other questions,
>> I don't know if Kenwood still supports these rigs or not. I repair my 
>> own.
>> Parts are getting to be a problem.
>> Proprietary Kenwood parts are no longer being made for the SDX, and 
>> the supply that Kenwood has is getting very low to nonexistent. There 
>> are NO alternate suppliers for Proprietary Kenwood Parts.
>> I have some parts and do occasional repair work on the TS-950SDX.
>> Hope this helps you find your problem.
>>
>> Mike
>> WZ5Q
>> from Deep Down in the Dark Dismall Swamps of the Calcasieu
>> http://www.wz5q.net
>>
>>
>>
>>
>>> On Wed, May 14, 2008 at 6:22 PM, bbbnntt <bbbnntt at optonline.net
>>> <mailto:bbbnntt at optonline.net>> wrote:
>>>
>>>     My 950 SDX has started developing heavy static on RX.  You might
>>>     hear well and within a minute or 2 the satic starts and ultimately
>>>     in about 3-5 minutes drowns out all of the audio.  Tx is fine. 
>>> Tried
>>>     3 different antennas, and they all work on other radios. Took the
>>>     amp, tuner and the scope out of line. Same RX results
>>>
>>>     Questions:
>>>
>>>     Are you familiar with this problem?
>>>
>>>     Are you aware of any solution?
>>>
>>>     Also heard that Kenwood no longer supports the 950 sdx or provides
>>>     replacement parts, and there is no alternate supplier? Is there
>>>     anyone out there who is sitting on a stockpile of 950 sdx parts who
>>>     repairs the rig?
>>>
>>>
>>>
>>>     Bob/kg2rp
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>>> <mailto:Kenwood at mailman.qth.net>
>>
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>
>
>