Dead Boss RV-3

[beatnik]

I got a Boss RV-3 reverb pedal from a clearance sale for a few bucks. But it's not working! It's completely dead, so no output and led won't turn on.

I opened it up to check some voltages. Being a digital pedal it's a fairly complex circuit. You can have a look at the schematic here

https://www.dropbox.com/s/vcpv3mv5s7dg8np/boss%20RV-3.PDF

I only have basic knowledge so what I could do was to trace the power supply voltage coming from the dc jack.

The polarity protection diode is fine and i got 9V until Q1. But after that first transistor, I got no voltage. And if i'm not wrong, should be 4.5V on C22, right?

I am thinking to replace Q1. Do you think that's the problem or I should check something else?

[theehman]

I'd guess Q1 is dead or C3 is shorted.

[beatnik]

thanks for the ultra fast response!

i'll definitely try to replace C3 and see what happens. Then will try to replace the transistor.

Can i sub 2SC2485 with something else?

[theehman]

probably with just about any similar transistor

[beatnik]

i've got some good news!

replacing q1 and the +5V regulator brought the pedal back to life!

Now the only problem is the led is not working, although bypass works fine.

There is a zener in series with the led, marked D2 on the schematic.

Should i try to replace it or the problem could be somewhere else?

[duck_arse]

the zener in series with a led is usually a low battery indicator. the zener needs whatever, 6V2? to allow any current through to the led. you could bridge it with a 1k resistor to see if the led lights, if it does, either the battery is low and the zener good, or .......