Chasing a hum '85 LPC

Discussion in 'Tonefreaks' started by Becker34, Jun 22, 2017.

  1. Becker34

    Becker34 Member

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    Got a helluva hum on my '85 LPC. I'm pretty green on dealing with electrical stuff, so any help/links are appreciated. Search made me more confused.

    The guitar is factory stock except for the straplocks. I've never farted around with the electric. The hum is there in every pickup selector position. It's a bit louder when switched to the bridge pickup. It goes away when I touch anything metal on the guitar except the straplocks. It goes away when I touch a tuner, string, bridge, tailpiece, pickup cover, jack plate, the metal part of the pickup toggle, you get the idea. It also pretty much goes away when I turn the volume pot - either one and/or both - all the way up to 10, or when I turn them down to 0. The hum is also there regardless of where, what amp or which cable I use. My '80 Standard is dead quiet.

    Again, thanks for any help.
     
  2. C_Becker

    C_Becker Dat Gibson smell Premium Member

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    If the hum goes away when you touch any metal parts, that indicates that your bridge ground is OK.

    Did you always have the hum or did it just turn up recently ?

    I would check the ground connections on the back of the pots and on the output jack first.
    Make sure the lugs on the volume and tone pots are properly connected to the back as well.

    A certain amount of hum is normal when playing high-gain (do you ?), even with humbuckers.
     
  3. DarrellV

    DarrellV Likes > Posts Silver Supporter Premium Member

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    Any chance of getting pics from the back with covers off?
     
  4. Becker34

    Becker34 Member

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    The hum has been there for a while. I don't remember if there was a particular event that led up to it. I chalked it up to being crappy electrical in the house, but it does it wherever.

    The hum is there regardless of if I'm playing it clean or high gain.
     
  5. spitfire

    spitfire Senior Member

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    Are you sure it is the guitar and not the cable or amp? Try another guitar and if possible the '85 LPC with another cable and amp.

    Also, try a different AC outlet for the amp. As always, simplify as much as possible. Guitar strait to the amp, no pedal board or stomp boxes.
     
  6. Becker34

    Becker34 Member

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    I've played it with different amps, different cords, different places. Hum's still there, still the same. I tried switching all of those things. It's the guitar.
     
  7. chasenblues

    chasenblues Senior Member

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    Have you checked the ground wire connection on the output jack?

    [​IMG]
     
  8. Becker34

    Becker34 Member

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    Output jack looks good.

    [​IMG]
    Control cavity pic for DarrelIV
     
  9. DarrellV

    DarrellV Likes > Posts Silver Supporter Premium Member

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    Ok, here's my guess from what I can see in the pic (thanks,BTW!)...

    The output jack may be soldered well, but I'm wondering about a cold or bad solder joint on the terminal strip.

    I see the bare wire attached to the top and the experts can tell me if I'm wrong, but I think that would be the ground to the tailpiece for grounding the strings. From your description, this is working.

    But what about the connections from where the shield from the jack is soldered to the lug and down from there to where it grounds to the plate?

    It looks to me like all the pots and associated parts (like the pup grounds) all go through that plate by way of the pots being screwed down onto it.

    A lifted ground here would un-ground all the components except the bridge wire, which is soldered on the top.

    Just a guess....
     
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  10. C_Becker

    C_Becker Dat Gibson smell Premium Member

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    What @DarellV said, I'd solder a wire to all the pot casings, see if it goes away
     
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  11. chasenblues

    chasenblues Senior Member

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    Theoretically that's what the plate is doing.
     
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  12. C_Becker

    C_Becker Dat Gibson smell Premium Member

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    I know, but I trust a solder connection more.

    EDIT: And it would definitely rule the ground connection out.
     
    Last edited: Jun 23, 2017

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