Troubleshooting Checklist
Check and tick off every step.
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Is the polarity of the supply voltage correct?
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Is the supply voltage in the range of 8-12V when the
device is turned on?
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Are all resistors placed right? Check the color bands.
□
Are the polarities of the diodes correct? The cathode
band must match the bar on the silkscreen symbol.
□
Verify the polarity of the electrolytic capacitors. Keep
in mind that the marking on the capacitor can point to
the (+) or (-) lead. The actual meaning is printed inside
the marking.
□
Are all ICs in the right place and with correct
orientation?
□
Are all IC leads plugged inside the socket? They can
bend and stay outside easily.
□
Measure the resistance between the power supply input
terminals and between the regulated 5V rail and ground
- they must not be shorted.
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