Serial Number of the unit: S1500117
Tester: Koji Arai
Test Date: Jul 22, 2015
1) Verify the proper current draw with the output switch off:
+24 Volt current: 0.08 A Nom.
-24 Volt current: 0.07 A Nom.
+18 Volt current: 0.29 A Nom.
-18 Volt current: 0.24 A Nom.
2) Verify the proper current draw with the output switch on:
+24 Volt current: 0.53 A Nom.
-24 Volt current: 0.07 A Nom.
+18 Volt current: 0.21 A Nom.
-18 Volt current: 0.26 A Nom.
3) Verify the internal supply voltages:
All look good.
TP13 -5.001V
TP12 -15.00
TP11 -21.05
TP10 -10.00
TP5 -18.19
TP6 -24.22
TP2 +24.15
TP3 +18.22
TP9 + 9.99
TP17 +24.15
TP14 +21.04
TP15 +15.00
TP16 + 4.998
4) Verify supply OK logic:
All look good. This required re-disassembling of the PCBs...
Check then pin 5 on U1 (connected to R11) and U4 (connected to R23):
U1 3.68V (=Logic high)
U4 3.68V (=Logic high)
5) Verify the relays for the power supply sequencing: OK
Turn off +/-24 V. Confirm Pin 5 of K1 and K2 are not energized to +/-18V. => OK
Turn on +/-24 V again. Confirm Pin 5 of K1 and K2 are now energized to +/-18V. => OK
6) Verify noise levels of the internal power supply voltages:
TP13 (- 5V) 13nV/rtHz@140Hz
TP12 (-15V) 22nV/rtHz@140Hz
TP11 (-21V) 32nV/rtHz@140Hz
TP10 (-10V) 16nV/rtHz@140Hz
TP9 (+10V) 9nV/rtHz@140Hz
TP14 (+21V) 21nV/rtHz@140Hz
TP15 (+15V) 13nV/rtHz@140Hz
TP16 (+ 5V) 11nV/rtHz@140Hz
Note that the input noise of SR785 is 9~10nV/rtHz@140Hz with -50dBbpk input (AC)
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