List of changes made by Mark KE6LVK:

>>> Circuit modification <<<<
Serial interface uses IC MAX232 instead of standard pasive components. Less components,
same functionality.

Negative voltage generated by MAX232 used to bias LCD display: it is not necessary for
many LCD display models, optimum voltage on brightness pin is around +0.5V, it is enough
to connect other end of potentiometer to ground (as in original). There is also one side
effect: change of load on RS232 interface results in small change of the negative voltage
resulting in change of brightness of display. I don't recommend that modification except
you realy need negative bias for your LCD.

Source of negative voltage for RS232 port is removed (it is part of MAX232), the pin
is connected to LED indicating running CPU.

Transistors that control power relays are replaced by IC ULN2804. Less components,
no change in functionality.

Simplified circuit for angle potentiometers, removed jumper for range switching. Please
select the resistor values to your needs.

Added 2 switches / buttons - no functionality with current firmware, no need to install
them on the board.

Modified connector to LCD display. PLEASE CHECK CAREFULLY WHETHER THE PIN LAYOUT IS SAME
AS ON YOU LCD DISPLAY MODEL, ESP. PINS 1 AND 2.


>>> PCB Modification <<<

The new design uses 2 layers, that is smart esp. for those that are able to use proffesional
PCB manufacturing equipment. Of course it is more difficult for those that make the PCB
using HAM means (like me). KE6LVK sent me kindly the PCB so I tried to assemble another
piece of AVROT on his board, I can confirm it is high quality design.

Some parts are moved outside the board - mains transformer, relays. As result the PCB is
smaller and there are no problems with different dimensions / pin distances of relays and
transformer. The price for it is the design is less compact - you have to care about
fixing these parts somewhere is the box. It is also possible to place the relays out
of the box, i.e. close to rotator, so the wires under high current are not comming to
controller box anymore.

LCD display connector - PLEASE CHECK CAREFULLY WHETHER THE PIN LAYOUT IS SAME
AS ON YOU LCD DISPLAY MODEL, ESP. PINS 1 AND 2. The model used by Mark is in this point
different from that I use.


>>> Software modification <<<

There is only one change in version 1.2 firmware comparing to 1.1 version. KE6LVK
reported problems with LCD initialization so it is necessary to increase the initial
startup time. I tested the circuit with 3 other LCD displays I have - all worked correctly
with original time, but the longer time has no negative impact on anything, so I can
recommend the change, just for sure.

>>> Reset signal <<<

The new PCB has the RESET CPU signal wires close to power signals (ULN2804). We have found
that sometimes a pulse on the IC can cause CPU to reset. It is recommended to block the
RESET pin with 10n capacitor to ground that fixes the problem. This can happen also by
original PCB design (but I haven't observed that in my piece). Just for sure...
The capacitor is not yet in both PCB designs!

I would like to thank Mark KE6LVK for his effort to improve the project and for his
support.

73 Pavel OK1DX