[Elecraft] SIDETONE OUTPUT TESTS

[Ken Wagner]

My K2(s/n 920) is NOT one with Low AF output. I've got plenty. I took the
same measurements that Tom Hammond did and results are as follows.

SIDETONE TEST RESULTS

1. Used two(2) 2.2ohm resistors in series for termination. Measured 4.2ohms.

2. Set ST L (052) to produce 0.4V p-p @ RP7-8 (I usually run ST L at ~30).

3. All O'scope readings are V p-p. All DMM Readings are RMS.
Readings taken at:
                        O'scope    DMM    Comment
RP7-8                0.40V     90.4mV
RP3-4                0.24V     89.6mV
RP3-6                0.22V     79.1mV
U10-7                0.22V     80.1mV
U9-8                  0.45V     155.6mV
U9-6                  0.46V     156.8mV
Spkr                   0.39V     131.6mV    @4.2 Ohm load. Same across
speaker

Note:  I get 1.9V(p-p)/640mV across termination load at ST L = 255. Same
across speaker.

Test Conditions:

  K2 #920
  U8-4 (KIO2) mod installed
  Sidetone sinewave mod installed
  KAF2 NOT installed. Appropriate jumpers installed.


Equpiment used:

  Tektronic 2225 Scope w/10x probe
  RS 22-174B True RMS DMM


Hope this helps...
73,
Ken K3IU