Home Forums GuitarPCB Build Support Mastadon Fuzz Pedal, not working :(

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  • #20789
    Lisa
    Participant

    Hi! I recently received my Mastadon Fuzz kit, and assembled everything like the guide said.
    However, there is no sound throughput from my bass at all. All I can hear is a single tone, which changes as I turn the knobs (vol, eq, wool, pinch). The LED lights up normally (in green and red).

    I double checked, triple checked, all my connections, but I can’t find the problem.

    The only thing that I have found, is that the voltages on the two transistors in the circuit are different from what it says in the guide:
    The guide said that the voltage readings on the two transistors should be:
    Q1 Emitter: 0V, Base 0,58V, Collector 1,2V
    Q2 Emitter: 0,88V, Base 1,2V, Collector 2,3V

    However, my readings are:
    Q1 Emitter: 0V, Base 0,58V, Collector 1,48V
    Q2 Emitter: 0,88V, Base 1,54V, Collector 1,0V

    I’m hope someone can help me out, or tell me which totally obvious thing I missed :’)
    Here are some pictures:

    #20791
    Barry
    Keymaster

    Where is D1?

    You must have D1 installed. Also I am doing a double take at the power jack so be careful you do not bridge connections. It could just be the photo I am looking at.

    #20792
    Lisa
    Participant

    Thanks for your reply!

    I thought D1 only needed to be installed when using a led on the main board.
    But I have installed it now, and checked if anything changed, but it’s still not working… Could I have damaged other components by not having D1 installed when turning it on?

    (the power jack is messy, but there are no shorts, I will insulate the connections just to be sure)

    #20793
    Barry
    Keymaster

    Yah D1 is protection for the whole circuit. The CLR does not need to be installed or the LED at D2 since they go in the 3PDT Wiring Board instead.

    I am seriously doubting you damaged anything.

    Make sure nothing is shorting like for example the back of the pots to the board etc…

    #20794
    Barry
    Keymaster

    Make sure the Black wire is not in the way when you insert the guitar cable into the Output Jack (mono).

    I cannot verify wiring from photos.

    #20795
    Barry
    Keymaster

    Make sure the In and Out Wiring looks like this:

    #20796
    Barry
    Keymaster

    Also double check you have two perfectly functioning cables. Make sure your power supply is 9v.

    Oh and I just noticed that you need to break the tabs off of your pots. Use a pliers and snap them off so your pots fit flush.

    I hope that helps but I am going to have to leave soon.

    If that doesn’t solve it hopefully someone else will jump in.

    #20797
    Billy
    Moderator

    Double check your IN tip ( I on the 3PDT pcb) is connected to the tip solder lug on the jack socket and not the ring

    Just put a jack in the socket and follow it around to the solder lugs

    Some of your solder joints on the IN and OUT sockets look dry reflow those and add a little more solder

    #20798
    Lisa
    Participant

    I have now put insulation tape on basically everything 😛 I am sure there are no shorts, and no cables in the way 🙂

    #20799
    Lisa
    Participant

    Thank you for the other posts 🙂 What is the use of breaking off the tabs on the pots?

    I will also check my cables and resolder the sockets, hopefully that will help, I will post an update!

    #20800
    Billy
    Moderator

    You’d need to drill a small hole for the tab to go through otherwise it won’t sit flat / flush when you put the pots through their drill holes

     

    So a lot easier just to snap them off

    As Barry says just use long nosed pliers to grip them and snap them off in a sideways motion

    #20853
    Lisa
    Participant

    It’s working! 😀

    So, in the end it was – of course – a stupid mistake that I made.
    I connected one of the jack sockets wrongly. I followed this image in the guide:

    I just soldered the wires to the tips named “T” and “S”, but in my case the T and R were switched … So I had to actually solder one of the wires to the “R” tip (in this image) 😛

    Still, thanks for all the replies, it was very helpful! (I also resolderd some connections, and insulated stuff a bit better)

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