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TROUBLESHOOTING GUIDE
If any problems occur, first check your wiring and soldering. Keep in mind that most problems are due
to poor soldering or wiring errors. Be sure that there are no solder shorts, poor connections or wiring
errors. Check that the battery is connected. Be sure that the transistors are in correctly. Check the
LEDs. The LED leads are hard to identify and can easily be wired backwards. The following is a guide
to help solve most problems.
Diode Position: Red and black leads shorted together. LEDs should alternately blink at 1Hz rate.
A. LEDs do not blink. Check that IC1 is in correctly. Check wiring around IC1.
B. Only one LED blinks. Check for open LED. Check transistor Q4.
C. Both LEDs blink together. One LED is in backwards.
Transistor Position Using Leads: B&E test leads shorted together. Rotate base current from
minimum to maximum. NP LED should light up when switched to NPN and PN LED should light when
in PNP position. OK LED should not light.
A. No LEDs light. Check that the battery is connected properly. Check for open circuit at R15, B or
E leads.
B. Only one LED lights. Check wiring and soldering. Check for open LED.
C. Both LEDs light at the same time. LED is in backwards.
Transistor Position Using Socket: Put the good NPN transistor into the test socket. Switch SW1 to
NPN position. Rotate base current control. The OK lamp should light. If not, check the following:
A. No test leads are shorting together.
B. The NP LED should be lit. If not, then refer to I.
C. Components around transistors Q1 to Q5 are in properly. Be sure no soldering errors exist.
D. Transistors are not in backwards.
E. Touch the collector of Q1 with the black (E) test leads. The OK LED should light. If not, then the
LED is either open or in backwards.
F. Look for a possible defective transistor or other component.
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