Help me fix my Star Wars sound board?

Marc_NJ

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Decided to play some Star Wars today..

Powered it on, and ever few seconds there is a click from the speaker.

In "self test mode" the click goes away (tests say all is OK).

During game play, the click seems to kill/reset the sound.

I pulled the sound effect generators one by one, click remains.

I pulled the speech synthesizer, click stopped.

It is almost as if the sound CPU is getting random resets?

Before I dive too deep in to this, I was hoping maybe someone has seen this before? Or can offer some advice?

Thanks
 
Decided to play some Star Wars today..

Powered it on, and ever few seconds there is a click from the speaker.

In "self test mode" the click goes away (tests say all is OK).

During game play, the click seems to kill/reset the sound.

I pulled the sound effect generators one by one, click remains.

I pulled the speech synthesizer, click stopped.

It is almost as if the sound CPU is getting random resets?

Before I dive too deep in to this, I was hoping maybe someone has seen this before? Or can offer some advice?

Thanks

I had a sound board that was making the click sounds. I had music but the problem was with the speech. I made some videos showing how to put the sound board in test mode first with a good sound board and then with my bad board. Then a video of me testing the bad board and finally what my fix was. This may or may not help with yours but it might give you some basic trouble shooting ideas.




 
Thanks for the information, and the detailed video.

My problem does not seem to be the same cause. When I ground the test pin, and let it go through all of the sounds and voices, it does so without issue. There is one point in the sequence where I hear the same "pop", but the rest of the sounds all play fine, with no issues.

When the pop happens, all sound seems to stop, as if the entire sound board is getting reset.
 
Check your voltages to your board set.
Edit: and by check them, I don't mean for a second, leave meter leads attached and see if they fluctuate after a few seconds and when the pop happens.
 
Doing some more testing, and during the sound board test, I get the click ONCE in the sequence, right after Darth Vader says "I have you now", then the pop, then "I'm on the leader".

That is also the only time I see "Speech Synthesizer Power Switch" change state. Driven by "PA5" from the 6532 PIA chip (pin 13), I also see the PA5 line change state only when I hear the pop.

Best I can tell, the 6532 get's all of it's input from the sound board CPU..

Any advice would be appreciated.
 
Check location 5F

I just got done fixing the EXACT same problem on my SW board. There was a constant "thump" or "click" sound every second or so. It ended up being a bad 74LS161 chip at location 5F on the sound board. I replaced the chip with a socket, pluggged in a new one and the sound and speach now works 100%.

I hope this helps.
 
I just got done fixing the EXACT same problem on my SW board. There was a constant "thump" or "click" sound every second or so. It ended up being a bad 74LS161 chip at location 5F on the sound board. I replaced the chip with a socket, pluggged in a new one and the sound and speach now works 100%.

I hope this helps.

Thanks for the tip.. Any procedure you can suggest to confirm that mine has the same problem? Did you notice some specific behavior that led you to replace this chip?

Thanks.
 
Thanks for the tip.. Any procedure you can suggest to confirm that mine has the same problem? Did you notice some specific behavior that led you to replace this chip?

Thanks.

Actually, I saw SaminVA's video first and that pointed me in the right direction since the problems seemed similar. I then just started checking the chips around that area of the board with a logic tester until I found the 74LS161 chip that was not functioning right.
Good luck!
 
Tubular Gearhead is correct, a logic probe can be your friend but it requires a little reading up on how to use one and you have to look up the data sheets of every IC you want to test so you know what each pin should be and like in my video I had a working board to compare to the bad board which really helped.
If it were me I would suspect the 6532, and or the socket
This is taken from Wikipedia(link below)
http://en.wikipedia.org/wiki/MOS_Technology_6532
The 6532 RAM-I/O-Timer (RIOT) was an integrated circuit made by MOS Technology, as well as second sources such as Rockwell. It incorporated 128 bytes of static RAM, two bidirectional 8-bit digital I/O ports, and a programmable timer. This high degree of integration made it quite popular in the late 1970s and early 1980s, as it could take the place of several different ICs. Perhaps its best-known use was in the Atari 2600 game console. This chip was also used in famous pinball machines made by Gottlieb, like Haunted House and Black Hole.
6532 ICs were available in 1 MHz and 2 MHz versions. The form factor was a JEDEC-standard 40-pin ceramic or plastic DIP.
My 6532 was bad but I was lucky enough to have a working sound board I could swap the chips into to test.
I think you can find them on Ebay for around $5.00 with free shipping the last time I looked or buy them from some of our regular chip suppliers if you have other stuff to order to save on shipping.
It may not be bad but if it doesn't fix it you will have a spare. It could also be bad sockets and you could have a bad ROM chip or bad ROM sockets also. The data from the ROMs I think are sent to the 6532.
But it could also be a problem somewhere in the speech section if the speech is all that's missing when you hear the pop. That's why with board repair theirs not always a straightforward fix.
Maybe you could find someone that lives close by that will be willing to test your sound board in their game and maybe they even have spare chips.
 
Did yours have NO speech? The video shows no speech at all, even in test mode. My board works just fine in test mode.

I probed the reset pin on the Microprocessor (fed from the LS161) and it is clean..
 
Did yours have NO speech? The video shows no speech at all, even in test mode. My board works just fine in test mode.

I probed the reset pin on the Microprocessor (fed from the LS161) and it is clean..
Did you not say you have one pop in the speech section during test mode?
My sound board started out totally dead. I tested the CPU by putting it in my working sound board and it was bad so I replaced it. Next I tested the 2 ROM's and they were good so I put them back in. I then swapped the 6532 and it was BAD so I took the good one from my working sound board and installed it in my bad board and then tested the board. The board now had all the sound but no speech. I also swapped the speech synthesizer chip with no change. I put the speech chip in my good board and it worked so I knew the chip was good. So in my case that pointed to the speech synthesizer clock generator section.
 
Not according to your video Sam.. The sequence of sounds on your video is the same as mine.. I just have that POP after "I have you now".
 
Not according to your video Sam.. The sequence of sounds on your video is the same as mine.. I just have that POP after "I have you now".

Ok gotcha, then it sounds like the sound board is for the most part working in self test mode so that might point to the communication between the main board and the sound board. I haven't looked at the schematics for a wile so I am not sure what section of the board that would be in. Maybe someone else can chime in.
 
Got a loaner Star Wars board test to test.. The problem is for sure on my sound board.

I swapped the PIA chip with the known good one, and there was no change. I still see the pulse on the PIA output (PA5) in sync with the pop noises.

So, what gets data to the PIA chip? is it direct from the microprocessor? Or does it pass through the LS374?
 
Got a loaner Star Wars board test to test.. The problem is for sure on my sound board.

I swapped the PIA chip with the known good one, and there was no change. I still see the pulse on the PIA output (PA5) in sync with the pop noises.

So, what gets data to the PIA chip? is it direct from the microprocessor? Or does it pass through the LS374?

You say you have a working sound board, if so try swapping both sound ROMs from the working board to your board and see if anything changes
PA5 goes to the Speech Synthesizer Power switch circuit so I don't think that would be the problem if only one or 2 speech sounds were missing but I could be wrong. It would not hurt to swap the other socketed chips also to rule them out but you could still have good chips but bad sockets.
 
Did that.. Swapped the ROM, and RAM chips. No change. I could shot-gun some of the LS chips, but I'd rather trouble shoot the problem than risk damage to the board by soldering unnecessarily.
 
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