Jmp-1 Has Nasty Squeal After Battery Change

Discussion in 'The Workbench' started by dlp4, Jan 27, 2018.

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  1. dlp4

    dlp4 New Member

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    I just replaced the battery on my JMP-1 and "reinitialized" it and now I get a high pitched squeal with no sound whether the guitar is plugged in or just the cable.

    I saw a video of someone reinitializing a JMP-1 and saw their data panel go blank momentarily when pressing OD1 + Clean1 but mine isn't doing that. I just get "-- --" then "00"

    The battery is good. It tested 3.3v before installing.

    Any ideas on what's happening? Thanks
     
  2. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    make sure you have the battery installed correctly. There's been a few threads on this, but, a quick search doesn't come up w/ anything right off. There's one thread that says the battery leaked, causing the squeal, but not sure of the specifics (it didn't say, other than that).

    I think there was a thread, where someone modified theirs, & put in a snap in holder, so they wouldn't have to do the soldering thing, they said the same thing, IIRC, unless, I'm mixing up threads...
     
  3. dlp4

    dlp4 New Member

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    Yea thanks. I did search the forum first. Both guys ended up taking them to techs
     
  4. ampmadscientist

    ampmadscientist Well-Known Member

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    Reprogram one of the patches (and test it) because the values may have defaulted to "10."
    It may not work until the patches have been programmed.
    OR
    The unit was damaged by static electricity.

    Unfortunately, many people who work on these (replace the battery, etc...) do not realize that they require special static protected soldering equipment.
    You should not be working on this (at all, in any way) unless you know how to use ESD certified equipment.

    **ONE tiny little spark of static:
    can fry the entire thing. :nono::nono::nono: No Shit.

    OR,

    the circuit tracks were damaged during removal and replacement of the battery....something that happens quite often when inexperienced people try to work on PC boards.
    Which is why you should hire a professional to work on PC boards.

    Working on PCB takes a lot of experience and special soldering equipment.
    It is not an easy simple job.
    Quite often, without the knowledge and tools ---the board is damaged.

     
    Last edited: Jan 27, 2018
  5. dlp4

    dlp4 New Member

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    The problem seems to have cleared itself. I replaced the tubes just to make sure it wasn't something simple and the problem went away. But when I reinstalled them one at a time to see which tube was bad the problem did not come return.
     
    tschrama likes this.
  6. dlp4

    dlp4 New Member

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    This is kind of odd. After replacing the tubes the squeal went away and the volume came back on the OD channels but I didn't check the Clean channels. I just assumed they were ok. When I checked the Clean channels with the 2nd set of tubes in both clean channels were very faint and distorted. So then I swapped those 2 tubes socket for socket and now both the clean and OD channels are working. I'm wondering if maybe the sockets are getting tired. I need to play with it some more and see. For a minute there I thought I had a dying tranny
     

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