TroubleshooTing and sysTem TesTs
5-46 powermax
65/85
Service Manual
Test 5 – Flyback circuit (DC minor voltages)
Symptom: Minor voltages are not present.
Note: Wear proper personal protective equipment (PPE) before testing powered equipment.
The flyback circuit is the source of the minor DC voltages in the power supply. It provides +3.3 VDC, +5 VDC, +24
VDC, and +48 VDC.
Check the voltages as described in the table. If a value is not within ±15%, perform the appropriate test later in this
section.
Volts DC Test points (use chassis for negative)
CSA units CE units
+48 J3 – Pin 1 J5 – Pin 1
+24 J1 – Pin 1 J3 – Pin 3
+5.0 J5 – Pin 3 J7 – Pin 3
+3.3 J11 – Pin 4 J14 – Pin 4
DSP board
J11 (CSA), J14 (CE)
Pin 4
J5 (CSA), J7 (CE)
Pin 3
Fan: J3 (CSA), J5 (CE)
Pin 4
Fan: J1 (CSA), J3 (CE)
Pin 1
Power board
Remove the connector covers to access the pins on the top-rear of the power board.