Service manual

PN 4237242C
2.5-9
INSTRUMENT DESCRIPTION
DATA ACQUISITION
2
Test Pulse Generator
A test pulse generator has been established on the SPAD card with two ICs. U40 is a logic chip
that establishes the pulses and U38 is the A/D converter used by the logic chip. The MD II
uses this test pulse generator to create a RAMP pulse train during the
PULSE TEST accessed
from the Service menu. The SPAD card processes this pulse train and generates a report. If
Auto Print is active, histograms are also displayed.
Interrupt Selector
The interrupt selector is responsible for signaling the CPU with an interrupt request and
determining what interrupt level to use.
Input
Outputs
P1, P2 - AT bus edge connector
Table 2.5-5 SPAD Card Input Connections
Connectors Connected To
P1, P2 AT bus edge connector (card uses +5 V from the AT bus)
J1 PLT PREAMP signal
J2 RBC PREAMP signal
J3 WBC PREAMP signal
J4
±
15 V
J5 Voltage monitor (for future use)
J8 10-pin power control
J9 RBC and WBC AIM voltage (to the URA card)