help with graphci eq / spectrum analyzer circuit

[sandiegoman]

I have a great graphic eq / spectrum analyzer that I am trying to reduce to a 5 x 5 pattern and putting the LEDs on 3' leads.

So I need to remove 3 bands, and 1 led from each column. I don't have a very good schematic, I could not find one online, but one did come with the kit I ordered off of Ebay.

I would like to change all the 3mm LEDs to 8mm Straw Hat Wide Angle White LED - Ultra Bright LEDs using 100-120ma and 3.2 - 3.6v.

I can't believe it, but they actually light up dimly when I swapped 1 row of them out, I would just like for them to have the max brightness.

I have attached the schematic and parts list, any help would be greatly appreciated.

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I am sure I need more wattage to drive the larger LEDs because they are so dim and they are on 3' leads...

I think what might actually be driving the LEDs is the CD4028BF. That seems to have plenty of power, but I am not 100% sure that is the role of that IC. It looks like the lm3915 is switching the negative on and off and the cd4028BF is providing the + voltage. There is a 10k resistor between each of the pins and a bc337 transistor:

Collector-Emitter Volt (Vceo): 45V
Collector Current (Ic): 0.8A
hfe: 100-250 @ 100mA
Power Dissipation (Ptot): 625mW
Current-Gain-Bandwidth (ftotal): 210MHz
Type: NPN

which then runs to the LED columns.

I am not sure if that will help.

Thanks!

Bryan

[pebe]

Your circuits are too small to read, but you will never drive LEDs at 100mA from a LM3915. The max current you can program it for is 30mA.

[sandiegoman]

Yeah, I figured that out now. I guess I will need transistors to provided a better sink. Thanks for your feedback.