STOP THE PRESSES: Ed I deduced some new information related to:
" I rechecked all of the pins on Plug #1. With the 220 V breaker
turned "ON" and the panel rotary switch turned "ON" and with
the plug connected to the board, I had:
Pin #4 53V with the meter set on AC and 24 V with the meter set
to DC (I got the same results testing Fuse F1)"
Dessalator told me via email over a year ago that pin 4 is 220
VAC. THIS CAN NOT BE CORRECT. Based on the Spec. Sheet for
T1 (7812 voltage regulator), the max Vi (input voltage is 35
Volts DC). This input voltage comes directly input from the
bridge rectifier/filter capacitor (C1). There is NO WAY FOR
220 VAC to be rectified and filtered and end up with 35 VDC.
However, 53 VAC would be rectified and filtered to
approximately 24-25 Volts AC.
To answer this questions we need to know: WHAT IS THE
AC VOLTAGE BETWEEN PLUG 1 PIN 1 AND PIN 4 with the
breaker on. If it is indeed about 53 Volts AC then
where does that voltage come from. There must be a small
transformer somewhere that steps the 220 VAC down to about
53 VAC. We need to trace the red wire on P1 pin 4 and
see where it goes. The transformer is not on the logic board.
The DC input voltage to the 7812 (T1) voltage regulator
must be at least 2 volts more than the output voltage (per
the spec sheet) and we know that the output voltage HAS
TO BE 12 VDC because that is what RY1, RY2, and RY3
require. So I believe there is definitely a problem with T1.
The 24 VDC that you read on pin 4 is just your multimeter
trying to measure AC voltage.
Lastly, it will be important to see if the 24 Volt DC out of T1
has burned up the control coils of RY1, RY2, and RY 3. You
could test them with a 12 VDC source to see if they still
energize (clicking sound). I'll try and post a photo showing
the pins to apply 12 volts DC to to test them.
Ed if you want to take this ongoing trouble shooting off the
forum please feel free to email me directly at
AgCEagle at comcast dot net