Boss CS-3 Led Resistor value

[ianmgull]

Hello,

I just finished completing the Monte Allums Opto plus mod. Everything sounds good, problem is the LED is not nearly bright enough. I measured the voltage and it looks like it's getting about 2.5v. I tested the LED on a dying battery I had (about 3.5v) and it was bright enough.

I figured I just needed to lower the value of the LEDs resistor to give it more voltage. I swapped what I thought was the correct resistor, but the voltage is still at 2.5v.



I circled the resistor I changed in the schematic above. Could someone please tell me if this is the correct resistor?

Thanks,

Ian

[Sava]

Try one about 1 KOhm.

[Sock Puppet]

Hi,

You won't see much of a change in the voltage drop as the LED "clamps" the voltage much like a zener diode would do.
Given that the 5.6V zener in there (for battery check) and the voltage drop across Q3 limits the available voltage & thus current to the LED there's not much you can do as the circuit stands, although a higher efficiency LED with maybe a 470R resistor is worth a try.

Hope this is of some help,

S.

[searoad]

what is the adaptor suggested? PSA or ASA?
if it is the ASA then u would need to short one diode and one resistor(IIRC) in the power supply section

[ianmgull]

Yea I finally realized that I had the ACA type and had to remove the extra resistor and diode. Duh!!!   Anyway it works pretty well now, but I'm curious... is the resistor I changed in the schematic above just for the LED? Or did I change something that was important. Thanks all!

Ian