LM3915 VU meter help.

Hello!
https://www.instructables.com/files/orig/FX5/67GS/FLROK12R/FX567GSFLROK12R.gif
Theres the schematic.

The problem? The last LED won't light up. I'm sure the LED's are in good condition, and everything else works perfectly. The only problem is they won't light up.

Oh and I used longer than 6 inches of wire, but it didn't seem to affect the other LED's!



Any thoughts?

Please and Thank you!

Is there any voltage across the LEDs?

Is the polarity of the LEDs correct?

What do you mean, everything else works perfectly?

Yes, the polarity is correct and yes there is voltage across them.

All the other LED's light up besides the last one.

LOL_PWND said:

Yes, the polarity is correct and yes there is voltage across them.

All the other LED's light up besides the last one.

Click to expand...

hi,
The LM3915 LED's light at 3dB intervals, the Vinput required to step from LED#9 to LED#10 is perhaps not achievable with you microphone.
What voltage do you measure at pin5 of the LM3915 at full drive to the mike.???