I finally did the W8JI keyclick reduction mod to my FT1000MP on Saturday. I
would be interested in any reports on my signal since then.
I started just after sunrise, and finished an hour or two after sunset --
interupted by numerous trips to the parts shelves in the barn, 150 feet of
slogging through the rain and deep snow, then the first 1-hour round trip to
Radio Shack (whaddya mean I don't have any .1 caps in the junk box?). And then
another (the pencil soldering iron chose this time to die!). And some family
things. If I had had everything in hand and worked continuously it probably
would have been about the 1.5 hours Tom predicted.
One small glitch; after I finished soldering the "green wire" on the RF board,
and lifted the radio up to feed the wire through to the IF board side, I found
a small copper grounding tab laying under the radio. About half an inch by
3/16 inch, that had been soldered to a board on one end and would compress to
make a ground connection when the board was installed. I thought I must have
knocked it off the RF board, but couldn't find any place where it would have
been attached. Tom's pictures of the RF board didn't show any (tho they don't
show the whole board) so maybe it fell off some other board. If any one does
this mod and sees where this tab would have been please let me know!
Also, in order to remove the RF board I had to pull up one of the white
wire-holding clamps that is just stuck to the chassis -- it was stuck too close
to the board for the board to clear it otherwise.
Anyway, after installing the parts (using two pots temporarilty for R1 and R2),
I adjusted for minimum clicks while listening on my TS940S in the narrow CW
mode. I found that the clicks went away when R1 reached about 98K ohms. From
there to the limit of 550K I really couldn't hear any change in the clicks --
no "deep null" as Tom described other
than the sharp dropoff at 98K ohms. There were changes in keying
characteristics throughout the range though very subtle. I settled on a 326K
fixed resistor for R1.
I could find no setting of R2, from zero to about 30K ohms, that made any
difference in key clicks or keying characteristics. For no good reason I ended
up putting an 8.2K ohm resistor in for R2.
Another thought on this mod: Unless you need to have C1 accessible for
experimentation, it seems you could just put it directly on the RF board
instead of running the "green wire" to the other side of the chassis.
I hope this has done the trick -- it really is simple enough to fix this
problem in any MP.
73/Jon AA1K
details: http://www.w8ji.com/keyclick_mp.htm
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