Help! Really odd pickup problem

Discussion in 'Gibson SG' started by mojo360, Jan 15, 2021.

  1. mojo360

    mojo360 New Member

    Joined:
    Oct 5, 2017
    Messages:
    1
    Likes Received:
    0
    Hey all. Not sure this is the right section.

    I have a problem with my bridge 498t. It went dead. I've checked all wiring/ resoldered it. Tried it in another guitar and it works for a bit (like a day or so) then goes dead again. It's definitely not the guitars wiring or switch. When it's out any guitar it shows the correct resistance on the multimeter. I've tried to wiggle the wire to see if it's somehow coming loose while in the guitar but it still shows up on the multimeter when I do that.

    I'm really stumped. It's the pickup but I don't know what it could be. I'd really appreciate it if anyone has any ideas?
     
  2. donepearce

    donepearce Well-Known Member

    Joined:
    Dec 12, 2012
    Messages:
    4,639
    Likes Received:
    4,004
    Location:
    London, new hearing aid project - exciting
    There is probably a broken wire in a coil that mostly just about touches. Then something - maybe temperature is enough to pull the contact apart. Switch to that pickup only then, at maximum volume measure the resistance across the jack lead tips. It will be about the same as the pickup on its own - just a bit lower. Do the same when it shows the fault. If it goes open circuit you will measure the 500k of the volume pot. Or it may go short, in which case you measure zero.
     
  3. kevbo82

    kevbo82 Member

    Joined:
    Aug 28, 2014
    Messages:
    61
    Likes Received:
    25
    Reminds me of an old motorcycle I restored and added a modern electrical ignition that I grounded with a nice ring terminal that was crimp/heat and had a low temp solder inside that would flow when you heated the shrink wrap on it. I could ride the bike for ten minuets fine then it would die and wouldn't start until cooled down. also oddly if I put it on the center stand it ran for hours without issue until I took it off the stand. Turned out the terminal snapped inside where I couldn't see it and the solder was the only thing keeping contact until the bike got warm enough to make that low temp solder flow again and cut ignition, but when the bike was on it's center stand it put enough pressure on the fitting where I bolted it to the motor mount to make contact again. Took me a long time to find that one!
     
  4. donepearce

    donepearce Well-Known Member

    Joined:
    Dec 12, 2012
    Messages:
    4,639
    Likes Received:
    4,004
    Location:
    London, new hearing aid project - exciting
    You just reminded me of a chap in my first ever job. He'd saved up and bought himself a brand new motor bike. So - at some point the neutral light wouldn't come on. He did a load of fault finding and decided the problem was the switch inside the gearbox. He took the whole thing apart and ended up with a pile of bits he couldn't reassemble so he took the lot back to the shop where they did it. They also changed the blown bulb.
     
    Go Nigel Go likes this.
  5. Steve D

    Steve D Well-Known Member

    Joined:
    Mar 15, 2019
    Messages:
    503
    Likes Received:
    532
    I had a car that was like that, except it almost always only cut off when I was pushing the engine little. Not a lot, I mean like driving over 55mph. Around the neighborhood, fine. Get on a highway going 65mph for a couple of minutes and there was a random chance that the engine would shut off and you almost die trying to roll out of traffic on momentum alone. Then I'd have to sit on the side of the road for 20-30 minutes until the engine would start again.

    This started after I had some work on my electrical system and the mechanic refused to believe there was a problem since he couldn't reliably reproduce it. He finally did realize that it was real and was caused by ... the work he did. But by then the car had been a death trap long enough that I wouldn't drive it except to get rid of it.
     

Share This Page