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Service Information
2001 reads these calibration constants from the device
during power-up. Note that data transmission is
performed serially.
The gain and filter control circuits include U101, U106,
AT101 through AT104, and associated components. Serial
control DATA from the Model 2001 is clocked into U101
with the aid of the CLK (clock) signal. Once all control
bits are shifted in, the STB (strobe) signal latches the con-
trol bits into the U101 outputs, and the control signals are
coupled through the four opto-isolators to the preampli-
fier module. U106 is a power-on hold-off circuit, which
inhibits random control information from being sent to
the preamplifier module when the instrument is first
turned on.
5.4
Special handling of static-sensitive
devices
CMOS and other high-impedance devices are subject to
possible static discharge damage because of the high-
impedance levels involved. When handling such devices,
use the precautions listed below.
In order to prevent damage, assume that
all parts are static-sensitive.
1. Such devices should be transported and handled only
in containers specially designed to prevent or dissi-
pate static build-up. Typically, these devices will be
received in anti-static containers made of plastic or
foam. Keep these parts in their original containers
until ready for installation or use.
2. Remove the devices from their protective containers
only at a properly grounded workstation. Also,
ground yourself with an appropriate wrist strap while
working with these devices.
3. Handle the devices only by the body; do not touch the
pins or terminals.
4. Any printed circuit board into which the device is to
be inserted must first be grounded to the bench or
table.
5. Use only anti-static type de-soldering tools and
grounded-tip soldering irons.
5-12
NOTE
5.5
Troubleshooting
5.5.1 Troubleshooting equipment
Table 5-5 summarizes recommended equipment for trou-
bleshooting the Model 1801.
Table 5-5
Recommended troubleshooting equipment
Manufacturer
Description
and Model
Multimeter
Keithley 2001
Oscilloscope
TEK 2243
5.5.2 Troubleshooting access
In order to gain access to the power supply card circuit
board to measure voltages under actual operation condi-
tions, perform the following steps:
1. Turn off the Model 2001 power, and disconnect the
line cord and all other equipment.
2. Remove the Model 2001 cover.
3. Install the power supply card in the multimeter.
4. Connect the line cord, and turn on the power to mea-
sure voltages (see following paragraph).
5.5.3 Troubleshooting procedure
The preamplifier and power supply cable are not field ser-
viceable and must be returned to the factory or authorized
repair facility for service. The power supply card can,
however, be serviced in the field, and Table 5-6 summa-
rizes troubleshooting steps. Refer to the schematic dia-
gram and component layout drawing at the end of Section
6 for component locations.
WARNING
Lethal voltages are present within the
Model 2001. Some of the procedures
may expose you to hazardous volt-
ages. Observe standard safety precau-
tions for dealing with live circuits.
Failure to do so could result in per-
sonal injury or death.
Application
DCV checks
View logic wave-
forms
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Table of Contents
Troubleshooting
