Diode/ Led question...

[jimmychung]

hi everyone- i was tinkering with my pedals yesterday- i wanted to make my boss pedal mods really shine with the superbright leds- that were for some reason coming out really dull.

I was wondering if you guys know the location of the resistor that is responsible for the brightness of the LED?  

For example- the super overdrive pedal- the resistor is r30. i lowered the resistance, to 470 ohm.. and .. it worked. the pedal is nice and bright.

what are the resistors responsible for led brightness for the Tremolo (TR2), and the Mega distortion (MD-2)?  I couldnt find them.

so, i took a piece of jumper- and just started touching the bottom of the board where all the soddering is- and started to just test each part (kind of like a temporary parallel connection) to see if the light would get brighter- thus locating the right resistor to take out and lower.

I came across diodes in both- (tremolo- D2)  (Mega dist- D5) and the light became superbright. so i soddered in a tiny piece of sturdy jumper on the underside the board where i was testing, from one end of the diode to the next- making a parallel connection.

it works- and the sound hasnt changed at all. the light is bright.

Is this alright? the fact that i didnt change the resistor- but messed with the diode instead?  does anyone know the resitor position for the tremolo and the Mega distortion that is responsible for the LED brightness?   how does me changing the diode connection- not affect the sound? and why does it affect the LED?

i have too many questions!

[Greybeard]

The diode you found is a zener and it should be changed instead of the resistor it is tied to. I recently did this to a Metal Zone and fried a transistor in the process. The diode needs to be changed to match the voltage your LED needs. Not the resistor on many Boss pedals. I ended up with a pedal that didn't work with a power supply anymore. :wink:

Greybeard

[MartyMart]

Quite  a few of the Boss pedals use a zener diode to "current limit" the LED.
The BD-2 is another, you can probably just remove that zener and
jumper  the space ( as you have done in effect ) .
There's often a resistor also adjusting "brightness" follow the trace from
the LED and you should find the zener/resistor responsible.
You can then adjust that resistor to give you different "brightness" of the
LED, depends on if you have an "ultra bright" or whatever.
Whilst its "powered up" I wouldn't just "poke around" with a piece of
metal, as you may well "short out" or damage a part !!

Marty.

[Greybeard]

That whole circuit is driven by a transistor with a very low current rating tho'.......... push too much to the LED and poof.................. no more ground in the power supply circuit.

Greybeard