Not having a Kenwood TKM-707 to actually measure the voltages, I cannot be certain, but looking at the manual (and that of the AT-140, along with my familiarity with the AT-140), I think I can help...(BTW, I think btrayfors has a TKM-707, so he might chime in here)
Originally Posted by ODarbin
Has anybody some information on wiring
the TKM-707 to the AT-140?
Thanks a bunch!
1) First off the B+ and ground are easy....they run off of "12vdc"....so, these are easy to wire up:
TKM-707 ant. tuner connector:
Pin 6 = tuner DC power = AT-140 "13.6" / Red
Pin 3 = GND = AT-140 "E" / Black
2) As for the "tuning control" / tuning signals:
TKM-707's ant. tuner connector pins:
Pin 5 = TS (? Tune Start)
Pin 2 = TT (? Tune Transmit)
The AT-140's operation is pretty straight forward...
A connected radio
(or external controller) sends a "Start" signal to the AT-140, by sending the "Start" terminal / white wire "low" (typically pulling it to ground, from it's nominal 7.5vdc - 8.0vdc), and this starts the AT-140 tuning process...
At this same time the AT-140 sends a "Key" signal to the connected radio
(or external controller), by sending the "Key" terminal / green wire "low" (again typically pulling it to ground, from its nominal 7/5vdc - 8.0vdc), and this triggers an ICOM
radio to send a low-power (typ. 10-watt) CW carrier.
Once the AT-140 has completed tuning, it sends this "Key" terminal back "high" (above 7.5vdc) and the radio stops transmitting, and the radio's "Start" line is then also sent back "high" (above 7.5vdc).
So, assuming the TKM-707's "TS" (tuning start?) and "TT" (tune transmit) levels are compatible with the AT-140, then they should work well together....
[please note that even if the 707's voltages are slightly different, the AT-140 has an internal switch that allows it to be used with non-standard "start" and "key" voltages...see page 6 of the AT-140 manual]
You should simply measure the "TS" signal (Pin 5) and see if it goes "low" for > 350ms, when you press the 707's "TUNE" button....and see if the 707 transmits a low-power CW carrier when you send the "TT" connector (Pin 2) low....
If these do as expected, then you're good to go...and wire as shown here:
Pin 2 = TT = AT-140's "KEY" / green wire
Pin 5 = TS = AT-140's "Start" / white wire
Pin 3 = GND = AT0-140's "E" / black wire
Pin 6 = Tuner Power = AT-140's "13.6" / red wire
The exact tuning description is explained on page 108 of the TKM-707's service
manual...(and if I could get the darn thing to post here, I would!)
I hope this helps..