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Help and ideas for repairs to Ampeg B2r

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  • #16
    Just a word of caution. When you start to solder/re-solder, work as quickly as possible with the smallest, lowest wattage tip you can. It is so easy to lift a trace or pad, and then you are back pedaling with jumper wires.
    Good Luck
    https://www.youtube.com/watch?v=7zquNjKjsfw
    https://www.youtube.com/watch?v=XMl-ddFbSF0
    https://www.youtube.com/watch?v=KiE-DBtWC5I
    https://www.youtube.com/watch?v=472E...0OYTnWIkoj8Sna

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    • #17
      Wow... I get home and have a few good ideas from friends, on top of all of these suggestions. I will let you guys know how it goes... Thanks!

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      • #18
        Sorry about the delay in response guys. I tried "Enzo's" idea: "Take a spare cord and plug it from send to return at the FX loop. Take another cord and plug pre-amp out right back to power amp in." I also tried the other suggestions, including the loop jacks, and all connect points. I am exactly where I started. Thanks for your help guys but it looks like I might just need to save up some more cash over time and give it to the pro's. If any other suggestions, please feel free to hit my email (but I will definitely recommend the forum to some friends of mine. It has got me back in tech mode with everything around my house that need fixing. Thanks, Chris~ An Ariatic Silence
        Last edited by cscarpenter; 10-21-2009, 05:04 PM. Reason: html removed

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        • #19
          You need to chop stick the board. Put it back in the chassis with everything hooked up. Feed a constant signal or play through it, and move stuff around on the board with a chopstick (non-conducting, of course) and see if moving or touching anything makes the sound cut in and out. You might be able to identify the problem that way. Be very careful and don't touch the electronics with anything but the stick. That is your next step.

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          • #20
            I'll try that first thing. Thanks

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            • #21
              Nope. Well it works, but on to big of an area. Can't really figure out what area it's coming from. So now I'm just lost on this...

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              • #22
                Well after all of that, I took it to Marc Ferguson of Fergs Amp Shop in Nashville. I can't remember what he said it was, but apparently one of the components had come apart. He actually had another one just chillin on his desk and didn't even charge me to fix the amp. Just the bench fee of like $40 and it works way better than the day I bought it! Just wanted to say thanks to this site, and I have kept my word. I have told all the guys I know to come to this site for any help. You guys have been awesome. So thanks again... cscarpenter

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                • #23
                  Can I reopen this thread? I am curious if cscarpenter found out "which" component failed.

                  I too am working on a B2R for a friend. It has an intermittent "crackle" sound. I am checking and resoldering the main power board. One thing I noticed, R54A and R54B, both 270 ohm, 5 watt resistors, in series with one another. Instead of having a dedicated spot on the PC board for each resistor and using a trace to connect them, they are connected in free air by having the leads soldered to one another. Does that seem right? Must be a fix after the PC board was designed?

                  Yes, I used jumpers on the Effects Loop and Power Amp In/Out jacks. So I am hoping that we have a solder problem on the board. Will report back.

                  Tom
                  Last edited by TomCarlos; 08-02-2011, 05:52 AM.

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                  • #24
                    It would be simply a HUGE coincidence if the exact same component was making the noise on yours. You just need to get in there and isolate the problem. Ball up your fist and whack the top of the amp. If the amp reacts with a noise, then there is a loose connection somewhere.

                    Plug a cord into the preamp out jack and feed the signal to some other amp. Is the noise on that feed? And same with the FX send, is the noise on that? Hook up the DI out to some amp or mixer, is the noise on that? Does the pre/post switch change anything? Plug a shorting plug into the power amp in jack, does that kill the noise, or does it remain?

                    And that ribbon cable from preamp to power amp board? Wiggle either end of that - make noises?

                    Those two resistors are intended to be that way. The layout pictorial shows them there, and even has a note about soldering them together before installing.
                    Education is what you're left with after you have forgotten what you have learned.

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                    • #25
                      As always, my appreciation to Enzo and others for sharing.

                      I think the problem has been fixed- a soldering issue in the Power Amp.

                      I was able to get a clean signal out of the Effects Send and Power Amp out jacks. So that meant the problem was in the Power Amp section. With a signal through the amp (an ipod and some music), I gently pushed down on the Power Amp board and could hear the crackling sound. So I knew this is there the problem was.

                      I carefully examined each solder joint and did some touch up soldering. As for R54A and R54B (270 ohm, 5W resistors), I had to do something with those puppies. So I changed them out- BUT- as you can see from the attached photo, I drilled a small hole in the PC board and brought the two leads together, through that hole, and then soldered above the board. I believe that doing this puts less stress on the leads. The resistors were not the problem. But I wanted to clean this up before turning the amp back over to the owner.

                      Anyway... 1 hour of playing and things seem to be back to normal.

                      Click image for larger version

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                      • #26
                        I like the drilled hole.
                        #1 on that.
                        You would think some of these amp manufacturers would catch on when it comes to laying these boards out.
                        Sheesh.

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