Prepared By: Peter Brandt Version: 08 – 20080415
Page
25 of 26
40-6640 Service Manual
6.0 Troubleshooting Guide
(see Section 3 for visual display of circuit boards)
No.
Symptom
Cause
Corrective Action
Low batteries.
Recharge or replace batteries.
On-Off Switch does not work.
Replace On-Off Switch Assembly
Wires are disconnected or broken.
Repair connecting wires.
1
Failure to start
using batteries
(instrument does
not turn on).
#1 Main Contol circuit board
does not work.
Replace circuit board.
Wires are disconnected or broken.
Repair connecting wires.
2
Failure to start
using A/C adapter
(instrument does
not turn on).
#2 A/C Receptor Circuit Board
does not work.
Replace circuit board.
Connecting wires between
circuit boards #3, #7, and #1 are broken
Repair connecting wires.
LED of circuit board #3 is damaged
Replace LED
3
Power is on
but indicator light above
On-Off Turnknob
is not working
#1 Main Contol circuit board
does not work.
Replace circuit board.
Connecting wires between
circuit boards #1 and #2 are broken
Repair connecting wires.
LED of circuit board #2 is damaged
Replace LED
4
Indicator light of
A/C Receptor Circuit
Board is not working
#1 Main Contol circuit board
does not work.
Replace circuit board.