[Elecraft] First An Apology

W3FPR - Don Wilhelm w3fpr at earthlink.net
Sun Jan 16 21:03:20 EST 2005


Ed,

BFO problem - be certain you have the correct capacitors at C173 and C174, 
then check the varactors D37 and D38 - they should be the smaller ones - 
1SV149 type.  As a check on the voltage swing being applied to the 
varactors, monitor the voltage at Control Board U10 pin 14 while in CAL FCTR 
mode and tapping BAND+ and BAND-, you should see the voltage change between 
0 volts and 8 volts.  If indeed you observe the correct voltage swing, look 
for the problem in the VFO area, carefully checking the components and 
soldering again - especially RP6.

On your 20/30 meter problem - you should obtain a very nice peak on 30 
meters with L9 near the top of the can (L9 does have the long slot slug, 
does it not?) - the slug location should be similar to that of L8.  Check 
L9, C22, C24, C25, and C29 for proper values, and check carefully for proper 
soldering of those components as well as K4B.

73,
Don W3FPR

----- Original Message ----- 

Now I have been chasing the BFO range. The high end of the BFO range is 
4918.2 which is quite a bit high from what the manual gives as an 
expectation (4916-4917). The low end of the range is 4914.8 which isn't even 
close to the expected range (4909-4912) as indicated in the manual. The 
resulting range is 3.4 which is too low. I have tried new crystals with 
virtually no change in range. L33 appears to be intact and constructed 
correctly in conjunction with R116. I even slipped a small piece of doubled 
over electrical tape between L33 and R116 to ensure that there were no 
shorts between the two. With the range being where it is filter alignment is 
pretty much out of the question.

And finally the pesky 20/30 meter receive problem. I do hear some faint 
signals but only with slug in L9 screwed all the way to the bottom of the 
can which seems odd. C23 doesn't seem to affect the receive level at all. L8 
and C21 offer very distinct differences in receive level when they are 
adjusted.

A wire from the antenna to C21 and C23 makes a huge difference in receive 
level. I have literally removed all the toroids from the 20/30 meter LPF 
area and checked for continuity, number of turns and correct cores. I have 
desoldered and resoldered all the other associated parts in the LPF. Since 
this appears to be band specific should I try the signal tracing procedure? 
I don't have a signal generator so I'm not certain if I can accomplish this 
with atmospheric noise or not.

I keep thinking I'm missing something simple that's right in front of me. If 
all else fails I'll send it back to Elecraft but I'm not ready to admit 
defeat just yet. So any ideas would be appreciated to point me in the right 
direction for either of these two issues.





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