LM3875 Gainclone Not Working and Stuck to Rail ...

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Hi ...

Today just build a gainclone LM3875 amplifier and found that it is not working ... output stuck to rail ... the circuit i used is i followed from the NS datasheet ...

BTW , i found that in the feedback path there is a capacitor in the schematic By NS. But i refer to some of the DIY projects schematics they are not included ... is it the cause of my problem ... ?

I need serious help here ... any feedback and suggestions are much appreciated and welcomed ...
 
Fig 1 or Fig 3?
 

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Ok.
Measure and post voltage on all 5 legs shown (1/3/4/7/8)
Measure from PS ground to each leg, straight at the chip.
Be careful not to let the multimeter tip slip and short to another leg.

By the way: I hope the chip is mounted to a heatsink and that you insulated it with mica+grease (and a screw-insulating nipple if needed).
Also, with power off, measure resistance to ground from leg 4 .
 
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