Keithley 2520 Service Manual page 84

4-12 Troubleshooting
Figure 4-4
Digital circuitry block diagram
Reset
E PROM
2
U13
DSP
U47
Data From A/D
SRAM
Converters
U27, U29
U38-U42,
U49
To Current and Voltage
ROM
U3, U4
Microprocessor
Source Control DACs
Model 2520 Pulsed Laser Diode Test System Service Manual
RAM
U2, U17
Serial
Interface
U5, U6
U15
16.78MHz
RS-232 Interface
U20
GPIB
IEEE-488 Interface
U19
To Display
Board Controller
Trigger
U46,
Q6-Q11
Digital I/O
U35
Trigger
Link
Digital
I/O