Blown Ampeg pf-500

Discussion in 'Amps and Cabs [BG]' started by Crawford C, Nov 4, 2018.

  1. I left my bass amp at home when I went off to college and finally got it up to school today when my parents came up. I was so excited, plugged in and turned it on, and played a single note before it cut out and the yellow fault light came on... I check the back of the cab (PF-210HE) and see that the speaker cable was broken, the metal part of the 1/4 in bent 90 degrees. Doing some research I saw that a half plugged in speaker cable can blow the amp. The amp lights up and the fan spins a few rotations before stopping and that's all it does. Any idea on what the repair is like? Swap a fuse and I'm good, or fried board?

    Thanks y'all
  2. Rumbledore

    Rumbledore Inactive

    Jun 2, 2018
    did you try it again with a different new not bent 90 speaker cable after yellow and see if it’s not yellow anymore?
  3. I gave it a try without the cable at all (it doesn't require a load), and it was the same.
  4. If you're lucky it blew a fuse. Otherwise getting a tech to order in a replacement power board and put it in will probably run more than a used one.
  5. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Full Compass sells boards for $151, and anyone with a screwdriver and an ability to take pictures to remember where each molex plug goes can install them. However, I advised Crawford in a PM to call Hodgy at Ampeg CS first and see if he can get an over-the-phone diagnosis of what happened before doing anything. But they don't open for another half hour.
    pie_man_25 and Wisebass like this.
  6. I spoke to Ampeg and the board definitely needs to be replaced. As Jimmy said, anyone with a screwdriver and a camera can do it, so I'll have to order a new board from full compass. Is there anything I can do with the fried board? Do people buy them for parts? Feels like a waste to throw it out.
    JimmyM likes this.
  7. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Take it to an electronics recycling plant near you. You might be able to sell it for a couple bucks to someone who wants to take a chance on seeing they can salvage anything from it, but if you get $5 for it, you'd be lucky.
    Crawford C likes this.
  8. bwildt


    Mar 21, 2017
    Wichita, Kansas
    I'll second Jimmy's post that the main board is easy to replace. I had bought a used PF-500 a few years ago, and had since discovered that it had the Rev C main board, which has been reported to be the cause of fault problems with the early 500's. It made me hesitant trust it enough to take it to gigs. Just last week I bought the main board from Full Compass. It was a fifteen minute swap. It almost took more time to remove all the screws in the cover.
    JimmyM likes this.
  9. Haha I feel you there. When in first happened I took off the cover to look around at the inside and it took forever. Glad to hear it's an easy swap though. I think I'll order one later today.
  10. I was erring on the side of not urging you to go poking around inside since you didn't check for fuse yourself. Screwdrivers and electricity is a bad mix for some but it sounds like you have it under control.

    Worst case is someone gets 10c worth of metals out of the old board, better than landfilling it I guess.
  11. JaxBassMaster


    Nov 21, 2018
    I wish I'd read this a few days ago as it would've saved me $45. I just got the email from the Ampeg service center that this is my problem. I have a Mesa Prodigy Four:88 on the way now so I'll probably wait on the PF repair but glad to know it's such a quick fix.
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