one segment in each LED not working

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one segment in each LED not working

Postby mike3 » Jul Tue 31, 2007 8:04 pm

hello .. just finished the Micro-Kim... two problems... one segment in each led isn't lighting.... the lower left hand segment .. and the 6502 chip did not work.. I pulled out one from a old computer.. and everthing works ... except the missing segment... any ideas... the rs232 works great with hyperterm... Great project,,, any help will be appreciated...

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Postby asm2750 » Jul Tue 31, 2007 9:46 pm

Might want to check the output pin from the RIOT and or the 74LS06 to the LED segment if the lower left segment doesn't light up on all the segment displays.

You might want to see if the segment physically lights up if its just one segment make sure you use a current limiting resistor if you try the physical check of the segment.

Hope that helps.
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Postby vbriel » Jul Tue 31, 2007 9:53 pm

Sorry about the cpu, this can happen with NOS parts. Which segment is not lit in the display. If I know that, I can tell you exactly where to look.

My guess is that one of your 100 ohm resistors under the display is not soldered, or a pin on the 74LS06 or 74LS38 (pin 4, 5, 6, 7, or 14). On the 6532 check pins 8-14.

Since it is a common segment not lit this should be easy to track down.

If you can't find any missing solder points, do you have a volt meter?

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Postby mike3 » Aug Wed 01, 2007 2:01 pm

thanks for the replies.... not sure .. but i think it is the "e" segment in each led ...

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Postby mike3 » Aug Wed 01, 2007 2:43 pm

Got it...... I reheated each 100 ohm resistor.. near the Leds.. and all segments now work....

Thanks again.... Mike
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