Tech 21 AR3-B foot switch no longer working

Discussion in 'Accessories [BG]' started by The Mackie, Dec 24, 2020.


  1. The Mackie

    The Mackie

    Dec 24, 2020
    I just joined this forum and was hoping someone on here might be able to give me some information about a problem that just occurred in regards to my foot switch suddenly having absolutely no signal.
    I have a Landmark 300, which I run through a Furman AR-117 power conditioner, and have the AR3-B foot switch.
    I was running the Landmark via the preamp output jack to Logic Pro X through a Focusrite Scarlett 18i20 3rd gen just to dial in a proper set of tones and had only had it in use for an hour or two before unplugging everything and shutting down shop for the night.
    The next afternoon I went to open up a previous recording session to overdub some DI bass tracks, and that’s when I was given that proverbially swift kick to the nuts, only to find that my foot switch was no longer lighting up and that now the only channel variance options afforded to me were through the front panel channel push button.
    I initially thought that maybe I hadn’t plugged in the cord to the rear foot switch input jack, but when I realized that wasn’t the case, that’s where the spiraling descent into disbelief, immediate troubleshooting 101 procedures ,OCD-style cable testing and making sure the input jacks weren’t loose came into play.
    But, alas here I am hoping someone may be able to offer up some insight, as to a possible tip for a DIY fix, or if there’s just something I may have overlooked and is a commonplace reason why the foot switch no longer works.

    Thanks in advance to anyone who may be able to offer up some advice. The last thing I want to do is have to hunt down a new one, but generally that’s how Murphy’s law seems to grind a fool down.
     
  2. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    Alright, let's start from step 1 and get this working somehow :D
    Can you post a picture of your footswitch, as well as trace the cable and a picture of it where it's plugged into your amp?
    I know you've done that a thousand times, but a second pair of eyes is a good step #1.
    I'll see what I can find for footswitch schematics in the meantime (and the photo of your fotoswitch is to verify we find the same design/not a different revision)
     
    The Mackie likes this.
  3. The Mackie

    The Mackie

    Dec 24, 2020
    I really appreciate the quick response. Hopefully these picture will be able to give you enough to work with.
     

    Attached Files:

  4. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    So no schematics yet, but at least found notes from Landmark. Looks like it uses a regular instrument cable for connection.
    Can you confirm, if you take that exact same cable, and use it to plug your bass into the amp, that it plays fine/no shorts and/or pops?
     
  5. The Mackie

    The Mackie

    Dec 24, 2020
    Fortunately, yes, the cable works with no shorts. Unfortunately, it never seems to be the simpler of the problems to fix.
     
    Sonicblaze likes this.
  6. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    Never is :)
    So, that leads us down to paths: the amp has an issue or the footswitch has an issue.

    According to Landmark, "
    To remotely change channels, use any standard passive
    footswitch or Tech 21’s Optional Footswitch"

    So, do you have any other single-button generic passive (non-powered!) footswitches that we can use to test with? If so, give it a shot.

    If not, how about something conductive like some wire that we can use to simulate a switch? Plug in one side of the cable to the amp, hold the other end (don't plug it into the footswitch), and use the wire (or paperclip or something else conductive) to connect sleeve and tip, and see if the channel changes. They don't really specify if it should be momentary or latching, so you may want to test both:
    make the connection and hold it there
    Make the connection and immediately break the connection
     
    Last edited: Dec 24, 2020
  7. The Mackie

    The Mackie

    Dec 24, 2020
    I’ll give the paper clip switch simulation a go right now. Before I post the results of that I should mention I have noticed occasionally while attempting to determine if there was an input jack connection I would be able to get the channels to switch when I deliberately insert the cable into the jack and would maintain a slight hold at each notch of the connection points.
     
  8. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    Awesome, then I'm guessing the paperclip test will work.
    If it does, next step will be opening your footswitch up to look for broke connections/shorts.
    Is opening it up something you're comfortable with? If so, give it a go, and post some gut pictures and let's see what we find!
     
  9. The Mackie

    The Mackie

    Dec 24, 2020
    The paperclip test was slightly improvised with a safety pin, but the results were definitive that it does seem to generate a signal from the head.
    I’ll pop this bad boy open in just one minute and send over the photographic evidence of its mechanical guts in just a few.
     
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  10. The Mackie

    The Mackie

    Dec 24, 2020
    Okay, so, the board is soldered onto posts that would require me to unsolder those connection points in order to see the full view of, really only the most pertinent aspect, of what you’ll most likely need to give it a proper diagnosis. Hopefully these images will suffice.
    I tried to get as much as possible, but it is in a rather dubious position to get a clear view, and only made even more difficult from my shoddy camera work.
    I just wanted to thank you for taking the time to help, especially if it’s possibly interfering with any holiday plans.
    You’re doing me a solid and that is golden, my friend.
     

    Attached Files:

  11. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    That's a pretty basic footswitch design, so although I didn't find schematics, shouldn't be too hard to see if it's easily fixable.

    So that 1/4" jack is enclosed so we lose a little bit of our view of a potential issue: the jack itself.

    Do you have a multimeter by chance?
     
  12. The Mackie

    The Mackie

    Dec 24, 2020
    That is one element of the equation I don’t have that will probably bring the chance of a definitive diagnosis to a grinding halt. I can unscrew the input to get a better view if needed.
     
  13. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
  14. So I don't see anything obvious there, but I wonder if the jack on the FS doesn't seat with your cable right. It there any chance something good happens when you push the cable in 95 % of the way in or so?

    Edit: shoot, y'alls are moving fast :).
     
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  15. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    Lol, I think we're on the same page: I'm guessing there's an issue with the jack. That's a pretty standard resistor-ladder style setup, where each footswitch sends a different resistance back to the amp so it knows which you pressed, even though the cable itself is only 2 wires. Not much to go wrong there
     
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  16. The Mackie

    The Mackie

    Dec 24, 2020
    Alright, I’ll get right back to you with the results.
     
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  17. The Mackie

    The Mackie

    Dec 24, 2020
    So, when touching the TIP & GND it does manage to switch the channels. It doesn’t fully engage the pedal though. The lights didn’t turn on and when the pedal is fully engaged it manages to bypass the signal to the A/B channel lights on the front of the amp. I’m guessing this is where finding the particular circuit that isn’t working will become difficult.
     
  18. The Mackie

    The Mackie

    Dec 24, 2020
    I had attempted to place the plug in at around 95%, as well, but it didn’t seem to affect anything unfortunately.
     
  19. Sonicblaze

    Sonicblaze Supporting Member

    Dec 11, 2016
    Omaha, Nebraska
    Wow, so yeah it does sound like something with the circuit itself is a bit broke. At this point, it would need disassembling/poking to see what's broke, or get a new footswitch.
    If you have anyone who does electronics stuff like this, hit them up. If you don't have anyone and want someone to look at it, PM me and we can figure something out :)
     
    The Mackie likes this.
  20. The Mackie

    The Mackie

    Dec 24, 2020
    Hey, once again I really appreciate all the help you gave me with this. I can at least rest assured that it’s not coming from the amp itself, so I’ll pick up a multimeter and take it from there, meaning I’ll most likely end up taking you up on the offer.
    have a great rest of your evening/morning and an even better tomorrow.
     
    Sonicblaze likes this.
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    Primary TB Assistant

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