Home Forums GuitarPCB Build Support Emexar Distortion Plus Help

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  • #10101
    Steve
    Participant

    Greetings,

    Let me start by saying that the Emexar board is lovely and very nice to work with.  I was beautiful before I started trying to remember how to solder – I did OK but you’ll notice a few places I had problems like the volume pot connection which is visible in the photo.  However, everything I tested came out good.

    The problem: When I switch to the effect with the back on and plugged into an amp, the volume drops to barely audible. The volume and gain controls do nothing.  When I opened it up to use the probe described on your site, I got a high-pitched oscillating tone as soon I switched in the effect.  I pulled the IC out of the socket (with power off) and no noise.  Using the probe, I got a good signal out working backwards from the output jack all the way back to pin 6 on the IC.  I get about 4 volts on pin 3 – I’m using a 9 volt AC supply and I get 9 volts at the jack.

    I’m at a loss for how to proceed.  Anything you can offer would be appreciated.

    Thanks,

    Steve

    #10103
    Barry
    Keymaster

    There are areas of concern on the board. The ones I point to in the image below may not all be bad because I cannot see them all clearly but I would inspect all of them. That said I would redo any areas the look like there are not properly soldered or perhaps hanging on by a thread. You can do this by reflowing and in the case of wires you may need to restrip and make a firm mechanical connection before applying the solder.

    Check all of the stuff in red and blue.

    #10104
    brd
    Participant

    If you had a good audio signal at the output jack using a probe, it is likely that you could have a bad ground to the jack. Check the ground connection to the jack also.

    #10126
    wilkie1
    Moderator

    It looks like the LED and CLR (R9) are installed on the EMEXAR board, but the wiring for S4, S5 and S6 are incorrectly placed on the 3PDT wiring board.

    #10494
    Steve
    Participant

    Uh Thanks for all the input. I just got back from a business trip to Chicago and haven’t been able to look at this. I’ll look over all of your suggestions and see what I come up with. Thank you.

    #10495
    Steve
    Participant

    Not sure where the “uh” in that last post came – I didn’t intentionally type it…

    #10498
    wilkie1
    Moderator

    I’m sure it wasn’t a “Duh!”

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