74LS47 Decoder / Drivers

Thread Starter

radioshack5209

Joined Nov 25, 2020
68
Hi:

I have a 3 digit display driven with 74LS47s. On one of the displays, the "6" has segment "a" lit and the "9" has segment "d" lit.
The other 2 displays do not light segment "a" for a "6" or "d" for a "9". All segments on the three displays are good. And it
appears that all three sections are wired the same. Is it possible that some of these 74LS47s display a "6" and "9" differently?

Thanks
 
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WBahn

Joined Mar 31, 2012
26,398
Move the driver ICs around and see if the problem stays with the display segment (indicating either a bad display or bad wiring) or if it moves with the driver.
 

dl324

Joined Mar 30, 2015
12,871
Is it possible that some of these 74LS47s display a "6" and "9" differently?
No. Standard part numbering wouldn't be very useful if functionality deviated that much.

From Motorola 74LS74 74LS47 datasheet:
clipimage.jpg

EDIT: corrected typo on part number
 
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