(Topic ID: 255243)

Bally 2518-17 LED locked on

By JethroP

5 months ago

Topic Stats

  • 11 posts
  • 3 Pinsiders participating
  • Latest reply 5 months ago by JethroP
  • No one calls this topic a favorite


Linked Games

No games have been linked to this topic.

    Topic Gallery

    There have been 5 images uploaded to this topic. (View topic image gallery).

    57A00561-8DBF-41D9-9024-FBC78986B8F1 (resized).jpeg
    8271E1F8-6AF8-48A0-B459-A2B0B2209F04 (resized).jpeg
    IMG_1999 (resized).JPG
    IMG_1998 (resized).JPG

    #1 5 months ago

    I have an old 2518-17 MPU I’d like to get working for a spare. After I received it I replaced all the brown sockets. It was previously modified per the Pinwiki to accept 2732 ROMs at U2 and U6 and I have verified the modification work. I’ve installed good chips at U6, U9, U11. There are no chips in U2, U7, U8, and U10. Powered up on the bench and LED is locked on. There is some abated corrosion, but I have confirmed good continuity checks on traces/components.

    What I have tried:

    Shorted pins 40 and 39 momentarily on the cpu chip; The LED did not turn off.
    U9 Pin 40 measures 5V
    Q1 and Q5 test good.
    There is pulse on U9 pin 3, 36, and 37.
    U9 pin 3, 36, and 37 measure 2.8V
    U9 Pin 2 measures 5V.
    U9 Pin 5 measures 2.8v

    Can I please get some additional troubleshooting help?

    #2 5 months ago

    The way I understand it the single ROM should be at U2 - U6 should be empty.

    #3 5 months ago
    Quoted from oldschoolbob:

    The way I understand it the single ROM should be at U2 - U6 should be empty.

    As I understand it, if your board is set up for a single combo ROM, then yes, it would be U2. But this board is set up for both U2 and U6 ROMs (2732's). So I think it I only need the U6 ROM to get the LED flicker.

    Just to be clear, I did have all the chips in to start....U2 and U6-U11 and still had the LED locked on. After that I removed the U2, U7, U8, U9, and U11.

    #4 5 months ago

    You're probably right - I've only done one 2732 conversion and it was in U2.

    Perhaps someone more knowledgeable will be along to explain this.

    #5 5 months ago
    Quoted from JethroP:

    So I think it I only need the U6 ROM to get the LED flicker.

    FYI, this is the case if you're using a Bally U6 ROM because the power on self test wholly exists in the U6 ROM.
    However if you're using a Stern MPU100 ROM set, you need both U2 and U6 installed to get past the first flicker because the startup code is split across the two.

    Anyway post some clear high res pictures of the board so we can see the level of corrosion. Is there any corrosion still under the U8 RAM socket that might be shorting pins?

    #6 5 months ago

    Bally ROM set, so I have installed also the U2. Doesn't appear to be any corrosion under the U8 RAM socket. I can take better pics in a while when the sun comes up!
    IMG_1998 (resized).JPGIMG_1999 (resized).JPG

    #7 5 months ago
    Quoted from JethroP:

    I can take better pics in a while when the sun comes up!

    Yes please, daylight makes a big difference to picture clarity.

    #8 5 months ago
    57A00561-8DBF-41D9-9024-FBC78986B8F1 (resized).jpeg8271E1F8-6AF8-48A0-B459-A2B0B2209F04 (resized).jpeg
    #9 5 months ago

    Regarding the dual 2732 mod, I don't see any jumper wire from U6 pin 18 to U6 pin 12.

    Regarding the U8 socket, pop off the plastic part so we can see what's going on underneath with the socket pin receptors in terms of corrosion. If you use a screw driver, make sure you don't pry against any tracks under the plastic which will damage them - use the picture below as a reference for where they run. Better if you use something plastic to pry if you have. Start on the TP6 side.
    If the pin receptors are in good condition (unlikely) and there's no corrosion bridging pins you can simply put the plastic socket cover back on.


    #10 5 months ago

    OK Quench....shoot me.

    I verified (not) the mod jumpers. Thank you for pointing out my error. I installed the missing jumper U6 pin 12 to 18 and got the flicker. Installed the remaining chips and got 6 flashes (no 43V connected). Thank you for the extra pair of eyes!

    #11 5 months ago

    Well I guess all isn't good yet. Installed in the game but isn't working. Here's a new topic...


    Promoted items from the Pinside Marketplace
    From: $ 19.99
    $ 229.99
    From: $ 11.95
    Playfield - Toys/Add-ons
    $ 26.95
    Playfield - Protection
    $ 32.99
    Lighting - Interactive
    Lee's Parts
    From: $ 99.99
    Cabinet - Other
    Lighted Pinball Mods
    $ 25.00
    $ 20.00
    Playfield - Decals
    DevilsMuse Arcade
    $ 159.99
    Lighting - Other
    Lighted Pinball Mods
    $ 85.00
    Playfield - Toys/Add-ons
    The MOD Couple
    $ 229.99
    Lighting - Other
    Lighted Pinball Mods
    From: $ 19.99
    € 4.99
    Flipper Parts
    $ 69.95
    Playfield - Toys/Add-ons
    $ 7,999.00
    Pinball Machine
    Operation Pinball
    $ 149.00
    From: $ 19.95
    Playfield - Toys/Add-ons
    PinBoss Mods
    $ 35.00
    Playfield - Toys/Add-ons
    Top-Notch Target Shields
    $ 96.95
    Cabinet - Shooter Rods
    Super Skill Shot Shop
    $ 1,099.00
    $ 10.00
    Cabinet Parts
    $ 89.99
    From: $ 220.00
    Playfield - Toys/Add-ons
    CzTV Mods
    $ 11.95
    Playfield - Toys/Add-ons

    Hey there! Got a moment?

    Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside