[Elecraft] Help - K2 Higher Noise Level with X1 Selected

[Don Wilhelm]

Mike,

It is on the KSB2 board somewhere.  Check everything on the end of that 
board containing the filter crystals.  Check T1 and T2 to be certain all 
the leads are well stripped,  tinned and soldered and be sure there are 
no shorted turns on those toroids.  I recently repaired a K2 that had 
the shorted turn problem because the builder use a flame to burn off the 
insulation from the toroid wires and got too much flame on the red T2 
wires when he tried to strip the green leads.

73,
Don W3FPR

On 6/9/2012 7:29 PM, VK1OO wrote:
> Hi Don,
>
> We have a long weekend here, so I've been able to get back to this.
> I reflowed RF board and KSB2 board, with no improvement.
>
> I then took out the KSB2, inserting the previously removed links and 
> the capacitor (effectively returning radio to pre-KSB2 state).  The 
> noise problem on X1 goes away.
>
> Your thoughts on what to look at next would be appreciated.
>
> Mike
> VK1OO
>
>
> On 03-Jun-12 6:59 AM, Don Wilhelm wrote:
>> Mike,
>>
>> If you do not find the solution re-flowing the solder on the RF board 
>> filter area, the problem source may be on the KSB2 board in the 
>> switching diodes and/or resistors at the filter end of that board, so 
>> for completeness, reflow those connections as well.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/2/2012 4:24 PM, VK1OO wrote:
>>> Don,
>>>
>>> The effect happens when the antenna is disconnected as well as when
>>> connected.
>>> And in SBB and CW
>>>
>>> SSB Filter Widths
>>> X1 = OP1
>>> X2 = 2.4
>>> X3 = 2.1
>>> X4 = 1.8
>>>
>>> CW Filter Widths
>>> X1 = OP1
>>> X2 = 0.7
>>> X3 = 0.4
>>> X4 = 0.1
>>>
>>> I assume something is going wrong in the 4.915MHz Variable Bandwidth
>>> Crystal Filter.
>>>
>>>
>>
>