KABTRONICS World Clock, Руководство по эксплуатации и сборке

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K A B T R O N I C S P A R T S I D E N T I F I C A T I O N
World Clock Kit Page 30
In Case of Difficulty
General Troubleshooting
The most useful tool you have when troubleshooting is your brain.
Start with the data showing the problem.
•
Is one display misbehaving or all displays?
o
The displays are driven in groups (2 for alpha-numeric, and 4 numbers) by the
SAA1064 28 pin IC below the group. If the problem is within one driven group,
suspect the driver.
•
Is the address test out of order?
o The addressing is controlled by the 22K and 33K resistors below the drivers;
miss-loaded resistors will cause addressing errors, or blank groups.
•
Are the boards enumerating at power up? The controller board will display the number
of boards found.
o
Is the number found equal to zero? That means the link is not complete. Check
the jumpering.
o Remove any display board without a jumper to simplify the problem to the
minimum number of boards.
This list is my guess at the cause of any problem in decreasing order of probability;
•
Wrong component loaded
•
Component loaded backwards
•
Bad solder joint causing open or short to adjacent pad
•
A clipped-off lead has stuck to the back of the board and is shorting out the circuit
•
The board is resting on something conductive shorting out the circuit
•
A component is bad because;
o
it was over heated when soldered (medium chance)
o
came that way with the kit (low chance)
o was damaged by static electricity when handled (unlikely)
•
The PC board is damaged or was fabricated incorrectly (very unlikely)
So take a close look at the back of the board looking for bad solder joints and clipped leads in the
area of the problem. Check for proper components and orientations. If you haven’t found the
problem after thoroughly checking out the above list, email me at:
customerservice@transistorclock.com