Dave,
I don't know the exact serial number, but the change has been quite
recent. I can state with certainty that the 2SC5739 shipped with KX1 SN
2059.
The motivation for the change was to use an RoHS compliant part.
Extra benefit is derived by having the plastic tab (note that the
shoulder washer should not be used, but it is still being packed with
the kit).
The 2SC5739 does seem to have higher gain at higher frequencies than the
2SC2166, so your 20 meter output may improve if you change it, but I can
offer no guarantees on that, the two devices are quite similar.
Should you make the change and find your power output is above 4 watts,
reduce the setting of R1 to the 4 watt level. The components in the KX1
PA output stage can be stressed at power levels much in excess of 4 watts.
73,
Don W3FPR
Dave G. wrote:
Can anyone help on the following...
At what serial number did the PA (Q6) change from a 2SC2166 to a
2SC5739??
Was there any other reason than getting away from the metal tab??
Better performance?? Or
TIA
--
Dave G. KK7SS
'65 MK III Sprite in Richland, WA
The Original Point and Click --- Smith and Wesson
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