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peavey 130 special

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  • peavey 130 special

    Chanel switching i am no expert but can use a meter ill try to keep this short.had lost my output volume. And found a bad chip socket. Replaced chip and socket. Back running again plenty of power.here is the prob i never had a foot switch for amp got one off ebay.i just dont seem to hear it switching. Looked at schematic cked the wireing on foot switchs tip of jack is for reverb and middle for switching cks fine with meter. I did download oweners manual.it says the normal gain is not affected by post gain control? If i turn post gain way down or off no matter switch position i have almost no gain. By turning normal gain if i dont use the switch post gain turns up gain and normal gain turns up also.i can get the amp to sound good like this. Mabe i am just chasing my tail thanks for any help

  • #2
    You can find schematics for most amps here:http://http://bmamps.com/Tech_sch.html

    Are you sure the footswitch is working properly?

    The footswitch controls/switches lead normal reverb on/off. Does your footswitch turn reverb on/off?

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    • #3
      FS is lower left in the drawing. It controls U2B. Does the output of that IC, pin 7, toggle up and down between +15 and -15 as you stomp the switch?

      If the post control controls the level in both channels, then Q15 is stuck on, either by fault itself or because the control signal to it is stuck, hence check U2B.

      Can we not use the word "gain" for level? The post gain control controls the level of signal. it can be confusing if we use the same word for both.
      Education is what you're left with after you have forgotten what you have learned.

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      • #4
        sorry about the gain a d level i am going to ck that pin monday thanks for come back ill get back again

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        • #5
          re 130

          Originally posted by bcclew View Post
          sorry about the gain a d level i am going to ck that pin monday thanks for come back ill get back again
          again i am no expert but i am trying i have been doing auto wiring and house wiring 60 years but this is different. looking at u2b and pin 7 black meter lead on chassis ground red on pin 7 i have 15v+nothing when switching stays the same thank for help

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          • #6
            How about at pin 6 of U2B ?
            Originally posted by Enzo
            I have a sign in my shop that says, "Never think up reasons not to check something."


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            • #7
              Originally posted by g1 View Post
              How about at pin 6 of U2B ?
              not sure ill ck tonight ill rite them all down on that chip.and get back thanks again

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              • #8
                ck pin 6 using ground from pin 5 i thought all but 2 pins had 15v? having said that i am going to put this on hold till jan 3ird or 4th i will be able to take the amp to work and set it up on a bench along with my computer and see with your help we can get to the bottom of this. have a good holiday andagain thanks for your help bcclew

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                • #9
                  Originally posted by bcclew View Post
                  ck pin 6 using ground from pin 5 i thought all but 2 pins had 15v? having said that i am going to put this on hold till jan 3ird or 4th i will be able to take the amp to work and set it up on a bench along with my computer and see with your help we can get to the bottom of this. have a good holiday andagain thanks for your help bcclew
                  jan 3 amp on bench going to ck pin 6? looking at the 8 legs on chip ub2 is the one near the index mark pin1? thanks

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                  • #10
                    Originally posted by bcclew View Post
                    jan 3 amp on bench going to ck pin 6? looking at the 8 legs on chip ub2 is the one near the index mark pin1? thanks
                    trying to my head back in this.looking at ub2 and q15 am i cking ac or dc volts thonks

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                    • #11
                      You are checking for DC volts. If there is a round indent in the IC, yes that will be pin 1.
                      Originally posted by Enzo
                      I have a sign in my shop that says, "Never think up reasons not to check something."


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                      • #12
                        Originally posted by g1 View Post
                        You are checking for DC volts. If there is a round indent in the IC, yes that will be pin 1.
                        thanks for come back.ok looking at ic pin1 0 p2 .072 p3 .093 p4 -4.75 counted from index mark on left as 1 stayed on left side down to 4 right side across from 1 as 5 so pin5 13.66 p6-3.3 p72.4 p8 0

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                        • #13
                          Here is how the IC numbering works:
                          Click image for larger version

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                          Originally posted by Enzo
                          I have a sign in my shop that says, "Never think up reasons not to check something."


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                          • #14
                            It seems you do not have the correct power supplies going to pins 4 and 8.
                            Do you have the correct + & - 15V at CR36 and CR37 ? (shown in lower right area of schematic)
                            Originally posted by Enzo
                            I have a sign in my shop that says, "Never think up reasons not to check something."


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                            • #15
                              sorry for the delayi am having trouble finding cr36 &37 on circuit board. i can see the 5w units is cr36&37 diodes?on the 5w pieces -27.07&-4.79 on one 24.78&13.63 on the other i dont no if this helps?getting a little confused thanks

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