Hey all,

I'm having a problem wherein I'm not getting sound on my TSPP. I've tried the procedure outlined at http://www.pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair#Sound_problems, and am pulling 5.58V and -5.58V from chip U30, and 13.9V and -13.75V from connector CN2. I've also attempted to reseat the ROMs to no avail, as well as tried the old standby of reseating the connectors on the board.

The questions I have are:

1) Do those voltages appear out to lunch? They seemed a bit on the high side, but I've never tested such a thing before, so I'm unsure if that's acceptable or not. Also, if they are problematic, is there a good path for troubleshooting them? I didn't see anything sticking out from the sound section on PinWiki, but admittedly haven't delved deeper into the page.

2) Is it common for the ROMs to become corrupted? I have a burner, so if this is something I should check, or should just burn a fresh set, I can do so.

3) Is there a good way to test the TDA2030A amplifier? Considering that I don't have any sound, I'm thinking it would be a bit odd for both amps to go, but stranger things have happened.

Any advice would be greatly appreciated, as this is somewhat new ground for me. Thanks in advance for your time.

Luke

Hey,

Nothing at all, but knowing that if U7 is out, nothing will work is good to know! Thank you.

Luke

And since I got ahead of myself, yes, the rest of the machine does work.

Luke

Hey,

Just a quick question: I have board 520-5300-00 Rev A. I looked into TSB 157 regarding flashing the sound OS to OS 8. I'm wondering if this is something that a) applies to me, and b) could be done by overwriting the existing EPROM at U7, then writing the sound code back to it when done? According to the TSB, LED1 is supposed to flicker a certain number of times based upon the sound OS installed; I'm not finding mine flickers at all. Thanks again.

Luke

Also, just wanted to mention I read the ROMs with my burner, and everything checks out on them.

Luke

And lastly, maybe a rookie dumb question: are the speakers/this circuit fused somewhere? Could I save myself some trouble by checking the obvious?

Luke

Hey Chris,

Sorry to keep grinding your gears, but any thoughts on flashing the sound OS? Thank you.

Luke

Also, to answer the question from a while back, no, I'm not getting chirps from the speakers on startup. Just somewhat of a "speaker with no signal going to it" hum.

Luke

Hey,

Planning on ordering a probe tomorrow. Thanks for pointing me in the right direction.

Luke

Hey all,

I received my microhooks, logic probe, and test clip over the past few days. From reading through the manual, it appears the CPU (U209) latches data into U5. I can see the that the 68B09E has a Vcc of five volts. As such, I should be able to test data being fed to U5 using my logic probe; however, I just want to verify that the chip is TTL before I do so. Also, is there a good place to latch onto the board with the logic probe to get my +5 volts? I'm assuming I can just grab a ground loop for the other side of things. Thanks in advance.

Luke

Thanks Chris.

Upon checking the manual (page 131), there's an explanation of the sound section (U209 to U5, to U6, and so on). I have the board with the Amtel processor (CPU/Sound Board II), and there's no real explanation of the sound circuit there. From what I can sleuth out from the schematic, it goes from U209 to U404, then...through U402, maybe? Is there someplace I might find a bit of an explanation of this circuit, because I'm really confused as to what's going on? I was able to check pins 24 through 31 of U209, and they are all pulsing, so that does let me know information is at least being put out there. Thank you in advance for your time.

Luke

Hey Chris,

Yes, it has made sound before. Worked fine for the better part of three years.

It's the 520-5300-00 board. There's a good chance that my reading of the schematic is way off in left field. Thanks again for your time.

Luke

Hey,

Sorry if I'm beating a dead horse here, but I'm having difficulty determining the path the signal takes from the CPU (U209) on to the ROM chips (U7). This is likely just my unfamiliarity with reading the schematics; if someone could either let me know the path I should be tracing, or give me a crash course in "hey, this is how you'd start tracing that path", I'd appreciate it. Thanks again for taking the time to help.

Luke

Hi again,

After some tracing back and forth, it appears the path travels from U209 to U414, U414 to U26, U26 to U30, then on to U101/102, then out to the speakers. I still have to determine which pins are used on each chip, but think I'm working my way forward. If this isn't correct, please let me know! Thanks.

Luke

I'm at idiot,

Did service bulletin 157, burned ROM U7, done. Sometimes I don't understand why I insist on things being hard. Thanks to all for the assistance.

Luke

And...back from the dead.

I had this issue come up again (sound OS gone), and I thought, "Oh, hey, I'll give this a try again."

Here's the deal. The M27C512 chip at U7 was screwed. I couldn't write to it after erasing it. Got a new chip. Put the sound OS on. I've fired up the machine, and am waiting for it to flash the sound.

The question I have for the masses: roughly how long should it take to flash this, and should LED1 be illuminated the entire time? I know that at the end of the process, the LED is supposed to flash, but I'm not getting to that point. I'm not sure if this indicates I should wait longer, or that something else is shot (if so, the board's heading out the door for repairs, as this is turning into a goat rodeo of epic proportions). Thanks in advance for any assistance you can provide.

Luke

Thanks for the heads up. I'm going to get in touch with Stern tomorrow and go from there.

Luke