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  • Bugera Infinium 333/FSB 104

    My foot switch, FSB-104 for the amp head Bugera Infinium 333 will not work.The switch was replaced several months ago and the head is 5 years old. I can manually push 1 of 5 buttons located on the head and it switches with no problem,the corresponding light on the FSB switch and head comes on.But FSB will not switch with your foot.
    This is the second time I have had this malfunction. Four months ago the same problem and a new switch fixed the no switching.
    I think there is a problem within the head, something that excepts the signal from the FSB when you tap the function you want. I have schematics for switch and head but I don't know any trouble shooting steps.
    I haven't had any luck finding someone who has had a similar switching malfunction.I contacted Bugera and they would only suggest I take the head to a repair shop.The nearest authorized repair center for Burgera products is 190 miles from my home.
    I would appreciate any suggestions. Please,no Burgera haters,or that's what happens when you purchase cheap equipment comments. I'm stuck with this Bugera 333 until I can afford a replacement,I need to have this switching problem repaired yesterday.I use the switching often during gigs.
    I live in Terre Haute,Indiana. If I could locate a repair shop within 125 miles I would consider driving the distance to have repairs done I imagine if paying a repair shop to fix the problem it would be extremely expensive. Best scenario would be for me to fix the head myself.
    I was a aircraft technician for 23 years and have the repair skills but I need guidance on repairing a guitar amp.I'm not confident tearing into the head unless someone can tell me what to look for.
    Thank You for any suggestion or repair ideas.

  • #2
    If you can post the schematic I'll help you isolate the problem.

    The question comes down to this. Are the foot switches hard or soft and do they run parallel to tour front panel switches or are they buffered.

    Hard switches latch - they are SPST or DPST switches that change states from off to on and make electrical connections.

    I doubt by looking at that pedal hard switches are used. It uses a 7 pin Din plug so my guess is the switches are momentary switches that simply make a temporary contact when you step on them.

    What does the actual switching are transistors or logic chips which act as flip flop switches. When a pulse from the switch is sent to one, it changes states from off to on. (much like your TV's remote control) When you click it again, it switches from on to off.

    The wiring to the switches may be wired in a matrix configuration and it can be difficult to decipher if you have a single chip doing it.

    My first guess is always go to the weakest items that can be most easily damaged by a user.

    This would be the switches, the cable or the DIN plug on the end of the cable or the socket on the amp.
    First thing to try is some zero residue contact cleaner to see if there's any improvement. If you don't have cleaner handy, take the DIn plug, stick it in alcohol then insert and remove it from the amp several times to see if the connection is simply dirty. Be sure its dry before you power the amp up for testing.

    Second the cable coming into the pedal itself is going to see the most wear. You need to tale an ohm meter and do a resistance measurement from the end of the wire where it gets soldered to whatever switch or the board and measure continuity to the Din Plug. You have to check all 7 wires (including the barrel which is likely DC Ground)

    Then I'd measure across each switch and see if the switches change state from Infinity to zero ohms (or very close to zero and infinity) main thing is it changes state. There may be other components in the pedal, diodes or resistors that prevent a clean go/no go on the switches. If you get no readings, try reversing the leads. If you still get no reading you may have bad switches.

    If all the switches check out and the cable reads good (while flexing it to see if its the wires in the cable that are stretched and making poor contact)
    The last thing you can check is the connector in the amp. Occasionally the female wire barrels which are pressed into the holes from the inside and simply click into place with a mini tab can come loose. When you plug the cable in, one of the 7 pin barrels gets pushed out of the connector back into the amp. It may only need to be reformed (bent) so the tab clips it back into place.

    If all looks good then you could use a mater again and measure continuity from inside the pedal to the inside of the amp. If you have continuity on all and it still doesn't work then the SS components that do the latching may be defective or whatever voltage they require isn't being supplied.
    That troubleshooting and repair is not for armatures. You have to know something about logic switching and have the tools, knowledge, and access to parts to make the proper repairs.

    If you'd had problems with the switch before, I'd throw it away and buy another. If they aren't available, then I'd find a shielded 7 pin DIN cord of similar length, Lop the female end off and rewire the new cord into the pedal. You have to create your own schematic/pictorial to show where the pin wires go to the contacts inside the pedal. The replacement cord may have different color code so you cant rely on any wire colored as being the same. You have to confirm each wire you are soldering goes to the right pin.

    The way I do these kinds of replacements is I remove one wire from the old switch, confirm the it goes to, find the wire that goes to that same pin on the new wire, then solder just that one wire in place. Then I start on the next and do the same thing over again until all the wires have been switched over (same thing you do swapping ignition wires in a car. You don't want to yank them all off because you may get the order wrong)

    Between that and the schematic you made you should be able to avoid mistakes.

    If the whole switch is rebuilt or replaces and you still have an issue you'll need professional help.

    I'm not a fan of putting silicone devices in a tube head. Tubes get hot as hell and heat is what makes SS components go bad.

    Comment


    • #3
      I suspect a faulty ground connection in the footswitch.

      Each individual switch is connected to a common ground. Perhaps the ground wire is broken or has become disconnected.
      As a human being, you come with the whole range of inner possibilities
      from the deepest hell to the highest states.

      It is up to you which one you choose to explore
      .

      Comment


      • #4
        thanks for the reply. Ihave to get back with you I do have schematics

        Comment


        • #5
          Thanks I will check out the ground

          Comment


          • #6
            Originally posted by WRGKMC View Post
            If you can post the schematic I'll help you isolate the problem.

            The question comes down to this. Are the foot switches hard or soft and do they run parallel to tour front panel switches or are they buffered.

            Hard switches latch - they are SPST or DPST switches that change states from off to on and make electrical connections.

            I doubt by looking at that pedal hard switches are used. It uses a 7 pin Din plug so my guess is the switches are momentary switches that simply make a temporary contact when you step on them.

            What does the actual switching are transistors or logic chips which act as flip flop switches. When a pulse from the switch is sent to one, it changes states from off to on. (much like your TV's remote control) When you click it again, it switches from on to off.

            The wiring to the switches may be wired in a matrix configuration and it can be difficult to decipher if you have a single chip doing it.

            My first guess is always go to the weakest items that can be most easily damaged by a user.

            This would be the switches, the cable or the DIN plug on the end of the cable or the socket on the amp.
            First thing to try is some zero residue contact cleaner to see if there's any improvement. If you don't have cleaner handy, take the DIn plug, stick it in alcohol then insert and remove it from the amp several times to see if the connection is simply dirty. Be sure its dry before you power the amp up for testing.

            Second the cable coming into the pedal itself is going to see the most wear. You need to tale an ohm meter and do a resistance measurement from the end of the wire where it gets soldered to whatever switch or the board and measure continuity to the Din Plug. You have to check all 7 wires (including the barrel which is likely DC Ground)

            Then I'd measure across each switch and see if the switches change state from Infinity to zero ohms (or very close to zero and infinity) main thing is it changes state. There may be other components in the pedal, diodes or resistors that prevent a clean go/no go on the switches. If you get no readings, try reversing the leads. If you still get no reading you may have bad switches.

            If all the switches check out and the cable reads good (while flexing it to see if its the wires in the cable that are stretched and making poor contact)
            The last thing you can check is the connector in the amp. Occasionally the female wire barrels which are pressed into the holes from the inside and simply click into place with a mini tab can come loose. When you plug the cable in, one of the 7 pin barrels gets pushed out of the connector back into the amp. It may only need to be reformed (bent) so the tab clips it back into place.

            If all looks good then you could use a mater again and measure continuity from inside the pedal to the inside of the amp. If you have continuity on all and it still doesn't work then the SS components that do the latching may be defective or whatever voltage they require isn't being supplied.
            That troubleshooting and repair is not for armatures. You have to know something about logic switching and have the tools, knowledge, and access to parts to make the proper repairs.

            If you'd had problems with the switch before, I'd throw it away and buy another. If they aren't available, then I'd find a shielded 7 pin DIN cord of similar length, Lop the female end off and rewire the new cord into the pedal. You have to create your own schematic/pictorial to show where the pin wires go to the contacts inside the pedal. The replacement cord may have different color code so you cant rely on any wire colored as being the same. You have to confirm each wire you are soldering goes to the right pin.

            The way I do these kinds of replacements is I remove one wire from the old switch, confirm the it goes to, find the wire that goes to that same pin on the new wire, then solder just that one wire in place. Then I start on the next and do the same thing over again until all the wires have been switched over (same thing you do swapping ignition wires in a car. You don't want to yank them all off because you may get the order wrong)

            Between that and the schematic you made you should be able to avoid mistakes.

            If the whole switch is rebuilt or replaces and you still have an issue you'll need professional help.

            I'm not a fan of putting silicone devices in a tube head. Tubes get hot as hell and heat is what makes SS components go bad.

            Comment


            • #7
              did you get the schematics? The problem is not the foot switch.My friend has a known good switch and it does not switch any thing. You can press any of four pedal switches and the light comes on but that's it,no switching. Continuity from the plug connector on the amp to a pcb board seems to be okay. The connector also looks good. I was an F-16 electrician and we would have pin retention problems often. The pins and connector are okay. I don't have much skill working on electronics. I think there is a problem with the amps signals from the foot switch but I'm not sure what I'm looking for inside the amp,also I'm having trouble reading the schematic that shows where the switching wires go that makes it switch. That darn foot switch isn't a stomp analog switch I could easily under stand click on click off. The electric jet f-16 consisted of wires going to boxes that were full of electronics we just changed the box. If the wiring,relays, and power source checked ok the box usually fixed the problem. This switching problem is complicated.
              I will pay for advice to fix this amp. That would be fair. I'm not poor but a repair shop would charge way to much!
              The biggest problem is I can not find anyone who has had a simiar malfunction of the foot switching. Also you can manually push the switch on the head and this works fine?

              Comment


              • #8
                did you try your footswitch in your friend's amp?

                if so, what was the result?

                As a human being, you come with the whole range of inner possibilities
                from the deepest hell to the highest states.

                It is up to you which one you choose to explore
                .

                Comment


                • #9
                  The footswitch works fine.The plug on the amp checked good.Wires to the first pcb board checked good.That is far as I can go. I don't know what to check out now.I do understand schematic symbols.Do you have a scanner so you could trace the signals from the switch plug to the components in the amp that control the output signals?

                  Comment


                  • #10
                    I do have a scanner and I have looked at the schematic but, like you, I'm having trouble making sense of it. I'll print it and see if I can think of some possible causes and measurements that you can take.

                    I checked the Bugera Forum and noticed that this is a common problem - I think I saw a post from you there too. I can check with a friend of mine who specializes in tube amps to find out if he is aware of the issue.


                    On the schematic that I have, I'm seeing the footswitch jack wired to connector X4 that goes to the DSP PCB but I'm not finding the DSP PCB or the other end of connector X4 on my drawing.
                    As a human being, you come with the whole range of inner possibilities
                    from the deepest hell to the highest states.

                    It is up to you which one you choose to explore
                    .

                    Comment


                    • #11
                      the schematics I sent you are messed up. I'm going to find another source to get
                      a useable schematic.I spent several hours tonight to attempt to match up wires going and coming. I also tried to locate resistors,diodes,capacitors etc. looking inside the amp head and comparing the schematics to pcb boards an they don't match up. I will send pictures of the inside of the amp and the pcb boards. You said you located post with the same problem I have not located anything that suggest a most common failure. If I could locate the pcb board that may fix my problem I will take a gamble and replace the board. Thanks again. PS I'm throwing the crap schematics away,I'm done trying to us them.

                      Comment


                      • #12
                        sorry I wasted your time with the schematics

                        Comment













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