Sounds missing on PB3

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    • Sounds missing on PB3

      I just received my F3 + PB3 from Italy and I'm trying to troubleshoot the audio problems. I don't have my multiboard yet so I can't test a different cart. On boot up, I'll get the sfx for the first 2 characters, but not the others. I'll also get the sfx for the bouncing ball animation. However I get no other music or sfx in-game or otherwise. I do consistently get those other previously mentioned sfx though, even after power cycling and leaving it on for a few minutes. I cleaned the edge connector and reseated the game a number of times. I also varied the voltage at the edge connector from about 4.9 to 5.1V and nothing changed the behavior. I lightly pressed on the mobo while it played and the behavior still didn't change. In test mode I was able to get the first sound to play one time and the effects that play while changing the volume work for a few seconds while I raise/lower the volume, but then stop.

      Any ideas on where to continue looking?
    • Your cart looks legit, so perhaps there really is an issue with your main F3 board - especially since you're also having Player 2 Input issues. That said, I would test it with a second game just to be 100% sure that you don't have a fault with the game PCB.

      What happens if you go into the Test Menu and check the music and sound effects in there? Try shifting the balance all the way left or right and see if that makes any difference. You can also try resetting the EPROM that holds system settings from inside the Test Menu.

      As for specific repairs on the F3 board, there's some resistor packs around RB17 that handle player inputs. Closely look for damage in that area of the board. Take a look at the capacitors around the audio amplifier to the left of the JAMMA connection as well. Damaged or failed caps can give you audio problems. If you have an audio probe, you can probe the audio going into the amp to find out if the amp has failed. I'm guessing that you have a different issue though if some sound effects are playing clearly. Also, check for bent or missing pins on all of the cart connectors.

      There's some writeups on other people fixing dead inputs with that board here:
      elgensrepairs.blogspot.com/2014/10/taito-f3-motherboard.html
      wiki.arcadeotaku.com/w/Taito_F3_Repair_Logs

      Unfortunately, these can be difficult boards to troubleshoot and repair, partly because there aren't any schematics, and partly because the game PCB blocks off almost the entire main PCB, making it difficult for probing on the component side. I had an F3 board that would randomly reset itself, and it was ultimately easier and cheaper to just replace it rather than spend all the time necessary to track down and repair the fault.
    • Thanks for the info. I ordered a new logic probe with speaker to test the audio section, so I'll give that a break for the moment. In PB3 I don't see a way to shift the audio left or right, I can only test individual sound samples and change the volume. I forgot to reset the EEPROM settings, so I'll give that a try later.

      For the inputs, I tested all the resistor packs and they test correctly. I also verified continuity from the edge to the various ICs. With my current logic probe I can see that activating the P1 inputs causes the buttons to tie to ground, but not so with the P2 inputs. Since all the ICs have parts of P1 and P2 controls, it seems really strange that only half of all those chips would stop working. I did see in the test menu an option to only have P1 or P1 + P2 controls, but it was set to use both. I might try swapping some of the components from the P3/P4 controls and see if that changes anything.
    • shess wrote:

      I gave the edge connector a good cleaning and then reflowed the solder to all the optocouplers and now the player 2 controls work. Regarding the sound, since I get some sound effects and some music, does it sound like a cap issue?
      Good job on restoring your player 2 controls.

      As for the sound, if some sound effects and music are working, then it's still a logic problem. An amp or cap problem would effect all music and sound effects.

      In the sound test, is it always the same music tracks and sound effects that work and don't work?
    • It will only play the 1st sound sample (ball launch) which, funny enough, doesn't actually get played during gameplay. I'm not able to play the songs in test mode that I can actually hear during gameplay. None of the other samples work in test mode and if I try and go back to the first one, it doesn't work unless I exit. And the only music played during test mode is during the volume test. And even then it's only played for a couple seconds before it stops. Maybe I should try and play the game in MAME to see what the behavior is.
    • shess wrote:

      Oh and once I got the coin insert sound in gameplay.... I should be getting my logic probe with audio today too, so I can start poking around. I may reflow the solder to the sound roms and ensoniq chips just as a precaution. With the probe, I'm guessing I start at the DAC and work my way backward?
      that could be a 74ls problem on the PB3 board. I'd also check the Eprom. These are easy to verify if you have an eprom reader/programmer.
      * Arcade-projects, the site where you get the most of your arcade games.
      * If you want Drama go to Neo-Geo forum ---Darksoft
    • I don't have the means to check the eprom contents unfortunately. I used the logic probe to check the data line on the DAC (TDA1543) and it squawks at the same time as the speaker, so it seems the problem is further back. I traced this back to a custom Taito chip. Not sure the best place to try probing now. The sound roms are e29-03, 04, and 05 and they feed into some MC74F373N and then the ensoniq chip on the mainboard. There are a lot of input/output lines so I was unclear where I should be looking.

      The good news is that my multiboard should be here by the weekend and that will confirm if the mobo has the problem.
    • To add some more details, I found that in test mode, when I sit on the volume, it will play for a couple seconds and then stop. In MAME the music plays indefinitely. When I look at the input/output pins with the logic probe, they stop flashing at the same time as the music. If I move to another option in the sound menu and then back down to volume, it will repeat that cycle again.

      I also probed the output enable pins on the sound roms, 3, 4, and 5. I see that OE on 4 and 5 are held high all the time, which might account for the lack of sounds in the game. I traced these back to a PAL, but since this is programmable, I'm not really sure how to test it. Maybe I should start looking at the sound CPU.