Tektronix PS 5010 - Page 210

FIRMWARE SIGNATURE ANALYSIS-ADDRESSIDATA BUS
I. Purpose
Verify address lines and buffer, and data bus and buffer. Data bus checks verify correct outputs of
GPlB chip (U1001) and keyboard encoder (U1421). If data bus signatures are not correct, use GPlB
chip or keyboard encoder tests
to locate problem. Also included are data bus signatures with key-
board encoder IC pulled to aid in troubleshooting. (Note that power-up self-test runs before signature
analysis routine, so CPU, ROM, and RAM must be working.)
II. Equipment required
A. Tektronix SA 501 Signature Analyzer (or equivalent)
B. Two TM 500 Flexible Extenders, Tektronix Part Number 067-0645-02
(I) = Inputs
Others
= Inputs/Outputs
Ill. Electrical conditions necessary to perform test
A. CPU,
ROM, and RAM functional (verified by power-up self-test)
B. Startlstop test point functional. Check for pulses approximately 5.5 ms apart (low true).
IV. Setup
A. PS 501 0 (on extenders)
1. GPIB address switch to instrument ID 22.
address
F~P~(I)
bus I HP5P(O)
buffer.. .I "PSP(I)
e ' 1 OA8(O)
. .
I
i.: - 10A8(1)
@' OOOO(1)
A
Data bus with
U 1 42 1 installed
,- - .- -I- - - -
Press
2. Mode jumper (J1320) as shown.
(I) = Inputs
(0) = Outputs
[=I Signature mode
~ata bus with
U 142 1 removed
3. Runlforce data jumper (J1220) to run position. After power-up self-test (displays 521 .), push
front panel ID button.
B. Signature analyzer
Connect to CPU board and set as follows:
Threshold
= TTL
Start = I Connect to SlS test point (TP1401)
Stop
=
I Connect to SIS test point (TP1401)
Clock
= 1 Connect to 02 test point, Jl 11 1, pin 2 (clock)
CPU board
Gnd
= Connect to ground test point (TP1011)
V. Measurements
Verify setup by taking
+ 5 V signature (81 3p). Take signatures on address buffer (U1210) and then
data buffer (U1202). This covers both buffered and unbuffered lines. U1211 signatures are given for
keyboard encoder (U 1 421
) installed or removed.
Fig. 9-4.