Subject: SCAN DEFEAT DURING XMIT FOR KDK 2016A



Anyone with a KDK-2016A has either fixed this or learned to live with

it, but here goes anyway:



The 4-channel memory scan on the KDK 2016A is designed to be active

whenever a) the memory channel switch is in the "scan" position and b)

when the RCV LED on the front panel is not lit.  To keep the receiver

tuned to an active channel once it's hit, the same signal that drives

the RCV light is picked off on its path via a white/yellow wire from

P24 of the main board to the display unit; the signal also goes to P9

on the synthesizer unit, where it is RC shaped and fed to the base of

Q12, whose collector circuit stops the scan when the LED comes on.



The problem is this:if you decide to talk to someone you hear on an

active scanned channel -- and forget to first move the switch from

the scan position -- as soon as you key the mike, the RCV LED goes out

(doesn't that make sense?) and bingo! scanning begins again.  The

effect of this is to spread yourself around a bit -- 1/3 sec on one

channel, 1/3 on another.... Kind of a primitive "spread-spectrum" but

not guaranteed to win friends on the other repeaters you may have in

memory.  If you notice the frequencies flashing by on the display, you

can catch this in time to save yourself some embarrassment, but there

is another workaround.  I installed this mod about ten years ago, and

it's still doing fine.



PARTS:2 small diodes, not at all critical; 1N1004s are fine

       1 small junk-box capacitor, .01 to .1, maybe tant or

           electrolytic

       abt 6" of hookup wire



PROC:-Cut the wire that goes from P24 on the main board to P9 on the

       synthesizer board and install a diode in the wire, with the

       cathode towards the synthesizer.

      -Connect the cathode lead of the second diode to the cathode of

       the first.

      -Connect the anode lead of the second diode, via the hookup

       wire, to P39 on the main board. (You can tap into the

       white/orange wire that goes from P39 to the display board. You

       guessed it -- this is the lead that drives the XMT LED.)

      -To the same junction, connect the + lead of the cap; connect

       the - lead to a good ground on the synth board.  Your choice of

       grounds, but the emitter of Q12 is OK, as is almost any other

       reasonable shield, metal, or board screw.  (If you couldn't

       find a ground, would you be a ham?)

      -Of course, all the standard good techniques (power off, good

       insulation, appropriate soldering iron and temperature-0, etc.)

       should be used.



Another mod that suggests itself on this radio is the replacement of

toggle switch SW6 (the red-handled WRITE switch) with a momentary.



If anyone has any questions about this proc -- or needs a copy of

2016A schematics -- contact me thus:

Allen, N2AEL
73 ES GL.