Gregg,
The problem appears to have been a batch of 1.6 ohm metal film
resistors (R19,20) that had 6 turns and produced a weak 10MHz or
thereabouts trap with C80,81 (4700pF). I believe Elecraft have sourced
some resistors with lower inductance. For the Brits, locally obtained
Vishay resistors (Farnell Part No; 550-012) worked. I could only get
1.5 ohm in 2W power rating but they had 1.25 turns and therefore only
1/23rd of the calculated inductance. After fitting I reset the drive
bias. The problem was initially identified by changing C80,81 and a
temporary cure effected by increasing the values to 5600pF or, in some
cases, 6800pF.
Scott at parts has the best American solution.
73
Ted G7BQM K2#4732
On 11 Oct 2005, at 01:54, Gregg W6IZT wrote:
What was the final resolution to the high current/low power out
condition? I
swapped C80 and C81, but this did not cure the problem. I recall
someone
saying that the problem was with two resistors (r20/21?). Is this the
case?
73
Gregg
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