[CQ-Contest] MP key click mod

Jon Zaimes AA1K jon.zaimes at dol.net
Sun Feb 23 14:05:42 EST 2003

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

More information about the CQ-Contest mailing list