Keithley 2002 Repair Manual

Troubleshooting
2-85
Bit patterns
Test 407.3 — Front end 750V range
Type
Pass/Fail
Fault message
Front end 750V range
Description
REFHI is tied to pin 1 of U420 and buffered to form BUFF. BUFF through R493 is tied to NET1,
pin 1 (R488). U428 connects R489 in parallel to the bottom leg of the NET1 divider. The divided
voltage (/500), R488 pin 4 is tied to the input buffer Q418 and U423 through U428 and Q422.
The buffered signal AMP IN is tied to the FWR, and, being positive, follows the non-inverting,
X10 path R452, Q413, Q411, U417, R453, U410, Q404, and U419 to pin 12 of U414. The out-
put of U414 is tied to the A/D buffer through buffer U403, R434, R462, and U222. The A/D buff-
er is configured for X1 gain.
Drawing reference
Analog Board; 2002-100
Components
Q418, U410, U417, U419, U420, U423, and associated components.
Bit patterns
Bit pattern* Register
—U400—
01110100
—U811—
00001101
—U224—
00010111
—U432—
10000000
—U810—
00000011
—U206—
01110000
—U203—
10001110
—U411—
11111111
—U809—
11100111
—U207—
11001111
—U221—
11101001
—U406—
01101110
AD_STB
MUX_STB
R1_STB
R2_STB
*Bits associated with register IC terminals as follows:
QQQQQQQQ
87654321 87654321 87654321 87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.
Bit pattern* Register
—U400—
01110100
—U811—
00001101
—U224—
00010111
—U432—
10000000
—U810—
00000011
—U206—
01110000
—U203—
10001110
—U411—
11111110
—U809—
11100111
—U207—
11001111
—U221—
11101001
—U406—
01101110
AD_STB
MUX_STB
R1_STB
R2_STB
*Bits associated with register IC terminals as follows:
QQQQQQQQ
87654321 87654321 87654321 87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.

Keithley 2002 Specifications

General

Resolution	8.5 digits
DC Voltage Accuracy	±0.0006%
Maximum DC Voltage	1000 V
Maximum AC Voltage	750 V
Maximum DC Current	3 A
Maximum AC Current	3 A
Connectivity	GPIB, RS-232
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Resistance Range	10 Ω to 1 GΩ
Model	2002
Category	Multimeter
Interface	GPIB, RS-232
AC Current Accuracy	±0.1%
Frequency Range	0.1Hz to 300kHz
Display	VFD
Type	Digital
Power Supply	100-240V AC, 50/60Hz
Current Range (DC)	100 μA to 3 A
Current Accuracy (DC)	±0.01%
Current Range (AC)	100 μA to 3 A
Current Accuracy (AC)	±0.1%
DC Current Range	100 μA to 3 A
AC Current Range	100 μA to 3 A