What Did I do...

Started by Switchfooter, May 16, 2015, 10:40:21 AM

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Switchfooter

Hi y'all,

I've been meaning to make an account here for a long time, so I figured now is a good time. I'm having problems with a Boss SD-1 overdrive I re-housed. At first, it was stuck on, but I figured out that I needed to insulate the raised strip that runs around the bottom plate of the enclosure. After that, it works as it should, but when the effect is off the LED still has a faint glow. Did I short something out?

Thanks,
-Tyler

Hope I posted in the right place  :)

darron

Did you replace the LED for a different one? I THINK I did that and had a similar problem years ago on a HM-2 when I replaced the regular 3mm red LED for a super-bright clear one. The difference I assume is that it relies on a specific forward voltage drop.

If someone else could jump in and confirm...
Blood, Sweat & Flux. Pedals made with lasers and real wires!

Switchfooter

Quote from: darron on May 19, 2015, 11:55:54 AM
Did you replace the LED for a different one? I THINK I did that and had a similar problem years ago on a HM-2 when I replaced the regular 3mm red LED for a super-bright clear one. The difference I assume is that it relies on a specific forward voltage drop.

If someone else could jump in and confirm...

Yeah, I changed the 3mm one for a 5mm

darron

if you want to keep that mod I'd be looking at replace D2. It's a 5V1 zener by the look of it. At a guess, maybe try 6V2? Assuming it's only on very dim and faint while in bypass that is.


Blood, Sweat & Flux. Pedals made with lasers and real wires!

PRR

> when the effect is off the LED still has a faint glow

Yes, it does.

The old-old LEDs were less bright and we never noticed. A new LED is much brighter for small currents so now we can see it.

If it is not a problem, ignore the glow.

If it really bugs you, try a 22K or 10K resistor directly across the LED.
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Switchfooter

Quote from: PRR on May 24, 2015, 02:41:08 PM
> when the effect is off the LED still has a faint glow

Yes, it does.

The old-old LEDs were less bright and we never noticed. A new LED is much brighter for small currents so now we can see it.

If it is not a problem, ignore the glow.

If it really bugs you, try a 22K or 10K resistor directly across the LED.
So just solder a resistor to both legs of the led?

Mark Hammer

Or replace the 3k9 resistor (R30) with a higher value, like 10k or 15k, depending on the brightness of the LED and the desired brightness.

Govmnt_Lacky

When you re-housed the circuit, did you make it true bypass? Did you carry over the diode and resistor between the LED and power?

There is a well known mod for Boss pedals when NOT using the ACA power supplies. Google it  ;D
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