Ibanez SR500 preamp problems

Discussion in 'Pickups & Electronics [BG]' started by Gallo, Jul 17, 2013.

  1. Gallo


    Jun 26, 2013
    Problems with Ibanez '96 SR500
    Bought a used SR500 a few weeks ago and am having some problems with the vari-mid system. One of the vari-mid pots (the middle frequency pot) didn't seem to work properly and there is a "dead Zone" on the D string from around the 4th fret to the 8th fret. The string just doesn't ring or sustain in that zone. The strings are less than two months old - Ernie Ball slinkies. I even replaced the D string just to make sure - no change. Also, even though this guitar has active electronics, it is not very loud with the amp. My passive bass is actually louder than this active one. I expected to have to use the attenuater on the amp input, but if I do, the bass can hardly be heard.

    When I opened up the preamp cover, I found two wires broken loose from the preamp board. I downloaded a wiring diagram from Ibanez and found that the original wiring in my preamp doesn't match their diagram. The board looks the same with the same solder connections, but, the wire colors to and from the pots are different - same colors, different order. So now I'm really confused. I re-soldered the broken wires where I thought they should go, but, who knows if it is right. The problems with the dead string and pot remain.

    Not sure what to do. I like this guitar, but it doesn't work properly. Can anybody explain the discrepancies in actual wiring vs the Ibanez diagrams? BTW, the diagrams for all their vari-mid systems seem to be the same.

    Maybe I should scrap the vari-mid and install some other pre amp? Or, can I get a new or used preamp board to replace mine with somewhere?

    Could the dead zone on the D string be caused by some other issue?

    Thanks for reading... I really want to fix this thing.
  2. evermelon


    Apr 20, 2010
    Phoenix, AZ
    Can you post pics? The wire colors might not be an issue as long as they are going to where they properly need to be. Is it the odd shaped board or the rectangular shaped board?..
  3. Gallo


    Jun 26, 2013
    srvlives4evr - here is the photo of the board.


    The broken wires were the green (third from the right in the three position rectangles) and orange (fifth from the right. They are both slightly mangled now from my holding device while soldering. The rest of the wires are in their original positions.

    The Ibanex diagram list the wire colors from left to right (WIRES IN RECTANGLE BOXES ONLY):

    YL, GN, BN,...WH, OR, GY,....YL, BN, GN,...GY, OR, WH

    Does this help?

    (BUMP) - still need some help with this. I'm convinced that the "dead" D string is not related to the preamp. I can detect the "deadness" even unplugged. Anyway, still having trouble with the middle frequency vary-mid circuit and would like some advice about this - anybody?
  4. Savio


    Jun 27, 2022
    Almost ten years later, but this might help someone...

    I have a board identical to this one and I can say that the colors are correctly arranged.