Troubleshooting 4-7
The offline switching power supply provides all power for the instrument while providing
universal inputs and power factor correction for the 110/120V line. The digital board runs off
of 5V and 12V supplies derived from the switcher. The +12VD supply is set to program the flash
ROM. (See Digital circuitry below.)
A constant-frequency switching supply runs off the +24VD supplies and generates all the float-
ing and output supply voltages for the analog board: +5V and ±15V, ±42V and ±85V.
Output stage
Figure 4-4 shows a simplified schematic of the output stage.
O
+
-
F
F
Q518
Maindrive
300K
Q521
Q523
Q525
Q507
-42V
-85V
HI Drive
Q503
F
+85V
Q504
Q514
+42V
HI Drive
Q500
Q516
+15Vf
-15Vf
Figure 4-4
Output stage simplified
schematic
Summary of Contents for SourceMeter 3A 2420
Page 2: ...Model 24203A SourceMeter Service Manual A G R E A T E R M E A S U R E O F C O N F I D E N C E...
Page 15: ...1 Performance Verification...
Page 31: ...2 Calibration...
Page 53: ...3 Routine Maintenance...
Page 56: ...3 4 Routine Maintenance...
Page 57: ...4 Troubleshooting...
Page 70: ...4 14 Troubleshooting...
Page 71: ...5 Disassembly...
Page 78: ...5 8 Disassembly...
Page 79: ......
Page 80: ......
Page 81: ......
Page 82: ......
Page 83: ......
Page 84: ...6 Replaceable Parts...
Page 102: ......
Page 103: ......
Page 104: ......
Page 105: ......
Page 106: ......
Page 107: ...A Specifications...
Page 112: ...A 6 Specifications...
Page 113: ...B Command Reference...
Page 124: ...B 12 Command Reference...
Page 125: ...C Calibration Programs...