59 lines
2.9 KiB
Plaintext
59 lines
2.9 KiB
Plaintext
2016A
|
||
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.
|
||
CONTINUED IN FILE 2016A.1
|
||
2016A.1
|
||
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, 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@NO3M.#WPA.PA.NA.USA.
|
||
73 ES GL.
|
||
|