[Elecraft] K6XX CW Tun Ind - Resistances and Voltages

[Tom Hammond]

Folks:

A couple builders have had trouble getting their Tuning Indicators to 
function properly.

I hope the following readings (taken from my working unit) will assist you 
in locating the problem

NOTE - USE EXTREME CARE when probing the pins of the 2211 IC to avoid 
shorting adjacent pins together. Bad thing can happen.

If anyone else gets significantly differing readings, I'd greatly 
appreciate knowing of it... may need to 'modify' my observations a bit.

73,

Tom  N0SS

-------------

K6XX CW Tuning Indicator - SMD Version

Representative Resistance & Voltage Readings

Test Conditions:

   CW Tuning Indicator UNplugged from K2

   Measurement device:  Fluke 187 DMM

   DMM Negative Lead connected to PC board header Pin 3 (GND)

   2211     Approx.
    Pin   Resistance
     1        6 M
     2       11 M
     3      400 k
     4        0
     5       >6 M
     6      >10 M
     7      >10 M
     8        6 M
     9      >10 M
    10        4 M
    11      850 k
    12       38 k
    13      >10 k
    14        9 M
-----------

DC Voltage Readings

Test Conditions:

   CW Tuning Indicator connected to K2
   K2 turned ON
   Band: 75M (4.000 MHz birdie)
   AGC: ON / FAST
   PRE: OFF

   Measurement device:  Fluke 187 DMM

   DMM Negative Lead connected to PC board header Pin 3 (GND)

   2211     NO-LOCK    IN-LOCK
    Pin    DC Volts   DC Volts
     1        5.0        5.0
     2        2.5        2.5
     3        0.2        4.8
     4        0          0
     5        1.6        0
     6       <0.03       0.1
     7        0.1        0.1
     8        5.0        5.0
     9       <0.01       0.04
    10        1.7        1.7
    11        1.0        0.1
    12        1.7        1.7
    13        2.8        2.8
    14        2.8        2.8
-----------

AC Voltage Readings

Test Conditions:

   CW Tuning Indicator connected to K2
   K2 turned ON
   Band: 75M (4.000 MHz birdie)
   AGC: ON / FAST
   PRE: OFF

   Measurement device: Tektronix 2236  X1 probe

   Negative Lead connected to PC board header Pin 3 (GND)

   2211     NO-LOCK     IN-LOCK
    Pin    AC Volts    AC Volts
     1         0          0
     2     50-100 mV   50-100 mV  (AF Input from 4 MHZ birdie)
     3      Random        0
           around 2V
     4         0          0
     5         0          0
     6         0          0
     7         0          0
     8         0          0
     9         0          0
    10         0          0
    11      Random     1.0-3.0
           around 4V
    12         0          0
    13         1.0        1.0
    14         1.0        1.0
-----------

73,

Tom   N0SS