Rangemaster weird voltages

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YellowDog
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Post by YellowDog »

Hi guys,

once again I'm fighting with a Rangemaster circuit. I'm super pissed off right now. It's reallly easy circuit but I can't deal with it.
It sounds as it should, but it has pretty weird voltages, additinaly the LED don't turn on when the circuit is on. I've made all the wiring as in any other pedal I've built, but this one definitelly don't like me.

I've built one on breadboard to test some trannies and caps, it works ok and the voltages are ok. In my "soldered" version I have for example -0,70V istead of -7.0V etc. My multimeter shows the volatages differently, but both circuits are the same and works the same. There is also a problem with LED, it don't turn on when the pedal is on. The catode gets the voltage but it's not working.

I tested the LED on breadboard and it's working good. I've duble checked all the wiring, footswitch, jacks etc. All parts are ok, there are no shorts etc. As I said, it sounds as it should.

I can't show u a photos of it's interior, but here are some pictures I've found on the internet which shows my way of wiring.

Footswitch wiring, standard true bypass, I have my LED reversed.

Image

DC jack/battery/input jack wiring. My input jack works like on/off switch for battery.

Image

And here's the circuit. Mine looks nearly the same. I've added input cap switch.

Image

I feel like throw it to the bin right now, never had silly problems like that with any, even a lot more compolicated circuits.
Guys, please :)

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alexradium
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Post by alexradium »

it looks inverted polarity

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POTL
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Post by POTL »

Hi, I suspect that the error may be in the most commonplace.
You are using a circuit with a pnp transistor that requires a negative voltage.
Power supply and LED connection for positive voltage.
Tell me, do you only use battery power or are you using a power supply?
Do you have other pedals?
Do you know that negative voltage pedals cannot be powered from a common power supply in your pedalboard?
Yes, I say obvious things because I don’t know if you understand the difference between different types of stress.
You sent dyal schemes of different polarities or you don’t understand the difference or you just didn’t waste time searching for the same shifts, but with a negative polarity.

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YellowDog
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Post by YellowDog »

Hey guys, thanks for replies.

Alexradium, every polarized components were checked. Everything is as it should be.

Potl, as for now I tested it with battery only. My power supply is on the road now, my friend was in need :D I have numerous pedals, both branded and my own build. I'm not a master builder, but also not a newbie. I've built numerous pedals for me and my friends, both negative and positive voltage - some direct clones, some modified ones and some my own designs. Never had significant problems with them.

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soulsonic
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Post by soulsonic »

If you followed these drawings exactly, then the voltage is definitely backwards from what would work. You need to swap the negative and positive battery leads, and the red (positive) must become ground and the black (negative) not attached to ground.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

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