Whirlwind audio issue

(Topic ID: 235839)

Whirlwind audio issue

By Baritonomarchett

5 days ago

Topic Stats

  • 12 posts
  • 2 Pinsiders participating
  • Latest reply 2 days ago by Baritonomarchett
  • Topic is favorited by 2 Pinsiders


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    #1 5 days ago

    Hi guys, some time no see.

    I am a proud owner of a whirlwind (system 11b).

    While attempting what I would call a trivial repair (PSU connection replacement with molex) I made a terrible mistake: I connected all the tensions backward (please, don’t ask).

    As soon as I juiced the boards, U18 and U17 made fireworks.

    I felt like loosing my best friend in a misadventure.

    After a night passed trying to recover all my self-confidence, the day after I went to check the damage extent (after connecting the tension in the right order). Having noticed that some IC was blown in the audio board, I removed it and lit the game. To my surprise, the game was still booting fine and I could play a game from the start to the end. You cannot imagine (yes, you can really) how lifted I felt.

    I then ordered new 1458 opamps, replaced U18 and U17 and fired everything up again: I had speech! But I could not hear the main theme. Replacing audio ROMs (U4, U19, U20, U21, U22) with fresh ROMs (I have an eprom burner) made no difference, nor replacing U26 and 27 (main program roms).

    After some game-testing I noticed that:

    - I have speech, but not all the speech (i.e. the cellar old man is missing)

    - I have sound FX, but not all sound FX (i.e. the outlain sound is missing, the cellar expulsion sound is missing, the right ramp sound is missing)

    - I have some music, but not all music (main theme is missing).

    I made the sound test and I have the wrong tracks selected while selecting the “files”: main theme is the “waiting for ball launch theme” etc. I will upload a video on youtube, just in case.

    A friend of mine will soon give me a bad cats audio board for testing, so it will be possibile to understand if the issue is there or in the cpu board.

    Now, the 1000 dollars question: what could be the cause of my (very donkey-me specific) sound issues?

    Thanks in advance for the help!

    #2 5 days ago

    Here is the video

    #3 4 days ago

    I made some testing with my (digital) oscilloscope and found that the cpu board PIA outputs no signal but receives data from the CPU. This made me think that it is possible that musics I can hear while performing music test are not "wrong" (the wrong file) but incomplete. Does anyone know if musics (let say the main theme) are made up of two audio lines instead of one?
    I bought a couple of MC68B21 from china and i will piggyback one of those over the cpu board pia to see if some missing music pops up.
    Any help would be much appreciated

    #4 4 days ago

    Just took a look at the schematics: in my understanding the audio amp is located in the audio board; both audio coming from the audio board circuits and cpu audio circuits meet there for the final amplification. Audio from cpu board arrives from J1, so by disconnecting J1 on the audio board should esclude audio coming from the cpu.
    Doing that I have the same exact audio I had before, which reconfim that the issue is (also) on the cpu board.
    Any help would be much appreciated, I feel a little bit alone on this :/

    #5 4 days ago

    So which plug did you get reversed that caused the damage? Since you are replacing the pre-amps, I am assuming you were working on the sound board? You may want to add a better description of what you did to cause U18 and U17 to blow. If you had to replace those two components, I would also start checking the components connected to those chips, especially the ones that sit between the chip and ground.

    As far as how to isolate the MPU sound section from the sound board. There are two sound tests incorporated into the test menu. The video you posted is from the Music test. If you advance the test menu a few more times, you should come to the sound test. This is supposed to test the MPU section of the board. If you don't get any sounds in this test, it doen't necessary mean the sound section of the MPU is bad, It may be working and you are not getting any amplification. You could possibly test for the MPU signal by putting the game into the sound test, and using your scope to look for an analog signal coming into the sound board at plug J1, pin 2.

    #6 3 days ago

    Thank you for the help. I reversed all the voltages from the iso to the psu board (dumb me: it was not my day). The result was two opamps visibly blown and the audio issue. In the end I was lucky, I must say.
    I will edit this message with the exact voltage messing as soon as I will have the schems at hand.
    I will perform the MPU sound (speech) test this evening.

    #7 3 days ago

    So, I sent:
    90V ac to the 5V voltage reg instead of 10v ac (pins 1, 2 on 3J3)
    10V ac to gnd and +-12V (3, 4 and 5, 6)
    10V ac to 100V line instead of 90V ac (8,9)
    It hurts to write such a thing

    #8 3 days ago

    Note to self:
    - music test interact with audio board
    - sound test interact with MPU board
    Ok, sound test performed: all good, sounds and the speach ("oh oh, looks like rain!").
    I must reconsider my assumptions...
    Any idea? Thanks

    #9 3 days ago

    If you sound test works, then we can assume that the amplifier section of the sound board is working, and the sound section of the MPU is working. The damage may be limited to digital section of the sound board. Since you are getting limited sounds during the Music test, it appears that the sound board is at least booting, and the CPU and memory chips are good. This leaves the sound generation portions of the board as suspect.

    You may want to consider how much work you want to put into trying to salvage this board. there are several chips that may be blown out that are rather expensive, and hard to find (like the 55516 CVSD chip at U11, or YM2151 at U3). There is not a lot of documentation as to how these chips work in the sound board, and at best you may be shot-gunning the repair. You may be better off trying to find a replacement fully populated D-11581 board, or a A-13971 board to replace it. Both of these pop-up on ebay from time to time.

    The A-13971 board is very similar to the D-11581 board, but it uses 1mb ROMS instead of the 256/512kb roms that are used int he D-11581 board. However, it can be used if you stack the rom images to fill the 1mb chips.

    The Bad Cats board you stated you have access to cannot play all the sounds your original D-11581 board in your WW could. It lacks the 55516 CVSD chip.

    #10 2 days ago

    Thanks. I am located in Italy, so spare audio boards are even rarer than in US. This makes the ebay route less appealing to me (also considered how relative a "fully tested and working" statement could be).
    Good call with the A13971 board replacement: are those used in system 11C eventually? That friend of mine have various pinballs and for sure can give me one of those for testing (and I can burn eproms by myself).

    #11 2 days ago

    I don’t think the A13971 board was ever used in a Pinball machine. The biggest sound Roms used in a system 11 were used in Riverboat Gambler, and it used 512kb chips. The board was used in the Super High Impact video game. Using it in system 11 games is discussed here:


    I have setup up one of these boards in a WW before, and after you create the Rom images, it pretty much becomes a drop in replacement for the D11581 board.

    Edit: I seem to recall the prototype Funhouse Machines used the A13971 board. However when it went to production they used a new WPC sound board.

    #12 2 days ago

    Ok. It's not an option then, unfortunately.
    I will keep you posted on progresses to come
    Thanks for the head up on the sound/MPU test: it made a big difference in the troubleshooting approach and put me on the right track

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