Table of Contents
Advertisement
HP 437B
Service Sheet BD1
Analog Board Troubleshooting
Microprocessor Control Circuit Verification.
1.
Press the Power Meter's PRESET/LOCAL
key.
a
For steps 3 through 12, refer to Figure 8-3.
5
Note
@
3.
Using a logic probe, verify the presence of TTL signals at A4U16 pins
3, 4, 7, 8, 12-18
and A4U18 pins 7, 9-13.
4.
Set the Power Meter's POWER REF to off.
5.
Verify a logical low level (<80V) at U16, pin 19 (CALOSC).
6.
Press the Power Meter's SET RANGE
key. Select range 3.
7.
Verify a logical high level at A4U16 pin 6 (NATTEN).
8.
Press the Power Meter's SET RANGE key. Select range 4.
9.
Verify a logical low level at A4UI6 pin 6.
10.
Verify a logical high level at A4U16 pin 2 (NSLOW) and a logical low
level at A4U16 pin 5 (NFAST).
11.
Press the SET RANGE key. Select range 1.
12.
Verify a logical low level at A4U16 pin 2 (NSLOW) and a logical high
level at A4U16 pin 5 (NFAST),.
@
8-32
SERVICE
Advertisement
Table of Contents
