Service manual

A DJM3.2 MANUAL
SET-POINT READOUT AND DISCHARGE TEMPERATURE FROM VOLTAGE
ON READOUT PINS (diagram follows)
Voltage (VDC) ºC ºF
1 10 50
1.5 15 59
2 20 68
2.5 25 77
3 30 86
3.5 35 95
4 40 104
R29 +
S
Q
M
N
e
g
itive -
R124 +
Dis Tem
p
Calc SP
Terminals
R29 is the discharge temperature reading
R124 is the calculated set-point reading
With the voltmeter set on the 20 VDC
scale measure the DC voltage across
R29 (the negative meter probe goes to the
resistor lead closest to terminal Q). The
readings are based on 10ºC per volt. A
reading of 0 volts = 0ºC. A reading of
2.15 volts = 21.5ºC.
NOTE: When in “service mode” the calculated set-point resistor reading is disabled. During
night cycle when the DJM3.2 terminal “K” is powered the reading taken at R124 is
not a calculated set-point reading. It is only a reading of the set-point knob. At night
the DJM3.2 will try to discharge at about 120ºF if the units design temperature rise
will allow a temperature rise that high.
XIX. DISCHARGE TEMPERATURE READOUT
Refer to the above diagram for location. Refer to Section XX for calibration.
For calibration purposes, the discharge temperature at the temperature sensor, can be obtained by
measuring the voltage across resistor R29. The ¼ watt, 1820-ohm resistor (colour code brown, gray,
red, brown, (brown or red)) is located next to terminals M and Q (Β). The readings are based on 10ºC
per volt. A reading of 0 volts = 0ºC. A reading of 2.15 volts = 21.5ºC. On DJM3's built after the fall of
1995 there are test terminals added to aid in obtaining this reading.
Page 23 Revised: 3/11/99