Wavetek 75 - Microprocessor and Main Memory Troubleshooting; Power off Reset Timing

6.3.2 Microprocessor and Main Memory
However, before beginning to troubleshoot this section,
check the appropriate dedicated circuits for correct
Generally, when the instrument is totally nonfunctional,
operation. Detailed reading of the circuit description is
i.e., display is unintelligible, random waveform data or
also very helpful before attempting to find and correct
nooutput, the problem is in the microprocessor section.
a problem.
Table 6-26. Microprocessor and Main Memory Troubleshooting
Figure 6-4. Power
Off Reset Timing
6-1 6
Scans by ArtekMedia O 2006
Fault
Nonfunctional operation
Check
U 30-3
(XTAL2)
U 30-2 1
(VDD)
U 30-7
(STBY)
U 30-6
(RESET)
U30-5 (IRQ)
U30-4 (NMI)
U30-40 (E)
U30-39 (AS)
U30-22 thru
-38
U14-2, -5,
-6,
-9, -1 2, -1 5,
-1 6, -1 9.
U37-7, -9,
-1 2, -1 4, -1 6,
-1 8.
U46-2, -5,
-6,
-9, -12, -15,
-1 6, -1 9.
Setup
N /A
Results Desired
4 MHz, sinusoid, approximately 0 to
4v.
>4.5 Vdc.
A high
A high
A high
A high
1 MHz at 50% duty cycle.
1 MHz at approximately 30% duty
cycle.
No stuck bits.
No stuck bits.
No stuck bits.
No stuck bits.