Fluke 43B Service Manual

43B
Service Manual
7-10
Measure TEMP on N501 pin 5 (=X503 pin 6); TEMP senses the battery temperature.
Measure IBATP on X503 pin 3 (= N501 pin 9); IBATP senses the battery current.
4. +3V3SADC must be +3.3V (supplied by N501 pin 65). If not correct, check if the
+3V3SADC line is shorted to ground. If it is not, then replace N501.
5. SELMUXn (TP591, TP592, TP593) supplied by the D-ASIC must show LF pulses
(0V to +3.3V, 0.5...3 seconds period).
6. Check TP536, TP537, and TP534 for signals shown below (typical examples,
measured signals may have different pulse amplitude and repetition rate).
TP536: if at a fixed level, replace D531.
TP537: if not correct, trace signal to PWM circuit on the Digital part.
TP534: if at a fixed level, replace N531.
0V
≈
500 ms
TP536
TP537
≈
+3V
TP534
≈
+0.5V
7.5.4 Keyboard
Proceed as follows if one or more keys cannot be operated.
1. Replace the key pad, and the key pad foil to see if this cures the problem.
2. Press a key, and check ROW0...5 (measure spots MS432..MS437) for the signal
shown below :
≈
50 ms
500
µ
s pulsesPress key
0
V
+3.3
V
Release key
If no key is pressed the ROW lines are low if a battery is installed; if the 43 is powered
by the the mains adapter only, the lines are alternating pulsing and low.
3. Check COL0...3 (measure spots MS438...MS441) for a +3.3V level. Then press and
hold a key, and check the matching COL line for the signal shown below:
≈
50 ms
500
µ
s pulsesPress key
0
V
+3.3
V
Release key
If not correct, check the connections from X452 to D471; replace D471.
For the ON/OFF key see 7.5.13.

Fluke 43B Specifications

General

Category	Power Quality Analyzer
Interface	RS-232
Volts AC/DC	Yes
Ohms	Yes
Continuity	Yes
Diode Test	Yes
Capacitance	Yes
Harmonics Measurement	Up to 51st harmonic
Display	LCD
Battery Life	Approximately 6 hours
Weight	1.1 kg (2.4 lb)
Data Storage	Yes
Amps AC/DC	0.1 to 1000 A (with clamp)
Power Measurement	W, VA, VAR, PF
Dimensions	50 mm
Current Measurement Range	Via current clamp accessories (not built-in)