Racal Instruments 3152, User Manual

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Maintenance and Performance Checks 5-23
Engine Board
Circuit Checkout
As described in the paragraph Main Board Circuit
Checkout, the Model 3152 is made of two boards. If the
engine board is removed from the main board, reinstall it
before continuing with the following checks. The following
circuit checks are performed on the engine board only.
Engine Board
Checkout
The “engine board” is the analog heart of the Mode 3152. It
contains the waveform memory circuit, high frequency clock
drives, and circuitry that drives the D/A converter. The
output of the D/A converter is routed directly from the engine
board to the output amplifier located on the main board.
Problems with the engine board circuits can be detected if
the Model 3152 accepts word serial commands and
responds correctly to word serial queries, however, fails to
generate waveforms. If there is a problem with the engine
board circuits, proceed with the checks given in Table 5-7a.
Before starting the following procedure, reset the Model 3152
to the factory default using the *RST command.
Table 5-7a Engine Board Checkout Procedure - #1
Ste
p
Test Point Expected Result
1 U27 pin 2 ±2.5 V squarewave, 1 MHz
2 U41 pins 1 to 11, pin 28 -0.8 V to -1.8 V ECL level squarewave, 1 MHz
3 U41 pin 26 ECL Level Negative going pulses; 2 ns width, 1 MHz
4 U29, U46, U51 pin 1 TTL Level, 50 MHz
5 U17-U20 pins 13-21 TTL Level, 1 MHz
6 U31,U32,U35,U36 pins 17
through 20
TTL Level, 1 MHz
7 U53-U57 pins 13-21 TTL Level, 1 MHz
8 U31-U32 pins 13-15 TTL Level, Positive going pulses; 20 ns width, 1 MHz
9 U35-U36 pins 13-15 TTL Level, Positive going pulses; 20 ns width, 1 MHz
10 U37,U38,U58,U60 pin 9 TTL Level, Negative going pulses; 20 ns width, 1 MHz
11 U39 pin 5 TTL Level, Positive going pulses; 20 ns width
12 U18 pin 4 ECL Level 100 MHz
13 U18 pin 2 ECL Level 100 MHz
14 U15 pin 2, U16 pins
2,3,14,15, U19 pins 2,3,9
14, U20 pin 14, U21 pin 6,
11, U22 pin 6
ECL Level 100 MHz