[Elecraft] KIO2

[Don Wilhelm]

Gil,

Yes, first concentrate on the low voltage at U1 pin 8 - be sure diodes D1,
D2 and D3 are oriented properly and capacitor C8 is correctly 10 uf and
properly soldered.  If that does not bring the voltage up to somewhere
between -6 and -12 volts, look at the oscillator components connected to Q1
(look on the schematic to identify which components).

Once you get a reasonable negative voltage on U1 pin 8, check it again - be
certain you have turned PORT ON in the K2 menu.

There are only 2 signal lines (other than ground) that you need to be
concerned with for communications with the computer - those are TXD and RXD,
and you can ignore the remainder for the time being.  Be certain the
miniature inductors indicate continuity first.  The computer will control
the voltage on RXD (J1 pin 3 and U1 pin 6), so if that voltage is not
correct blame the computer port or the cable.  TXD (J1 pin 2 and U1 pin 5)
on the other hand is controlled by U1 on the KIO2 board - it will be either
a positive or a negative voltage greater than 3 volts (up to 15 is allowed),
but should not be anywhere near zero volts.  Whether it is positive or
negative depends on the voltage at U1 pin 12 (either near zero volts or near
5 volts - and this signal originates at the K2 MCU).

I hope that helps you locate the source of the problem.

73,
Don W3FPR

> -----Original Message-----
>
>
>         Hi fellows. Can't manage to communicate between computer and K2.
> Through control program or HyperTerminal verified that serial port is
> functional on the computer ( Win XP ).
>         Can hear Q1s signal loud.
>         Here are some voltage measurements made this morning.
>         U1-1 14.12 shud be 14
>         U1-2 -1.3mv    "        .1
>         U1-3 13.65     "        14
>         U1-4 -5.4mv    "       .1
>         U1-5 -.017mv   "      -8
>         U1-6 -2.38        "      .1
>         U1-7  13.66      "      14
>         U1-8 -3.13        "      -9
>         U1-9  0            "       0
>         U1-10   0          "      0
>         U1-11  4.89      "       5
>         U1-12   4.98      "      5
>         U1-13  4.89      "       4.5
>         U1-14   0          "       0
>         U1-15   4.89      "      4.5
>         U1-16   4.89      "      5
>         Wonder if getting voltage on pin 8 would to proper level would
> cure the problem?
>         J1-1   0        shud be    0
>             2   -.011       "         -8
>             3   -2.36       "         .1
>             4    6.27        "        4.5
>             5    0             "         0
>             6    5.62        "         5.5
>             7    0             "         0
>             8    14.12       "        14
>             9    8.18         "        8
>         Voltages on J2 are in limits.
>         Any help would be greatly appreciated.
>                         Thanks   Gil   K8EAG
> _______________________________________________
>