Street Fighter 2 Audio issue

Lazerhawk

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Hey yall! I just got my first game and have been doing some minor fixes. Everything is working 100% with the exception of sound. When I bought the game the guy told me he thought it had a loose connection or something because the sound cuts out. He said to fix this he turns the game off and back on again and usually the sound comes back. So after I fixed my button issue I was playing and moving the cab a bit while playing when the sound cut out. I power cycled the game and it came back but I didnt touch the game this time. After about 5 minutes the sound went out. I have never had the sound come back unless I restart the game so I really doubt its a wiring issue. Smacking the side of the cab or the speaker grill has no effect either. Does anyone have any idea what is causing this?
 
Just turn the sound "pot" left then right while power is off. Then do the same while pushing on it slightly the again, left to right, while pulling slightly on it. That should get it. If not let us know.

Mine is probably the cpu processor on the a board.

The other things to look at are the usual suspects. Bad caps. audio amp, wiring, and probably speaker. These are the newer boards so I thing it is just a dirty pot or bad connection.
 
One thing I forgot to mention was, I was playing when the sound went out then a few seconds later there was a harsh tone that wouldn't stop until I turned the power off. Ive done a fair amount of soldering, following instruction, but not much troubleshooting. I found a couple articles since I posted this, sorry should have looked harder, and I saw a few people having problems with the z80 cpu thats processing the sound? Should I locate the z80 chip and follow traces to the caps if playing around with the pots doesn't solve the issue? Would the cap problem be obvious like leaking caps? I don't have much experience but it doesn't seem like a dirty pot, bad speaker or loose wire. Once the sound it gone there's no getting it back unless you do a reset.
 
I recently bought one with sound not working. I did not even power the thing up and just went ahead a pulled the z80 chip. Now I am just waiting on some chips and when they are done I will buy a socket for this cpu.

http://www.ebay.com/itm/180706341229?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I don't think the cpu is you issue but it very well could be. I have had several z80 cpu chips that work for a short time then muck up. Especially if the chip is a Zlog chip.

Try the adjusting the sound pot first and maybe clean it.
 
One thing I forgot to mention was, I was playing when the sound went out then a few seconds later there was a harsh tone that wouldn't stop until I turned the power off.

That would point me towards the Z80 (if it is a Zilog) or the SRAM chip if the Z80 is another brand, something is crashing the audio system and the sound generators are getting the last byte over and over again until you power off.

Should I locate the z80 chip and follow traces to the caps if playing around with the pots doesn't solve the issue?

No, the caps are in the amp section and will not be directly connected to the Z80.

Would the cap problem be obvious like leaking caps?

No, usually completely undetectable by eye, unless they are physically damaged, you would need an ESR meter to test if they are ok.

I don't have much experience but it doesn't seem like a dirty pot, bad speaker or loose wire. Once the sound it gone there's no getting it back unless you do a reset.

There is no way an amp can crash like this, bad caps, bad volume pot or bad amp chip are not faults that will clear with a power on, you have an issue in the digital circuitry, on these boards if the CPU is a Zilog then that is the most likely culprit, I have seen a couple of boards where the Z80 is borderline like this, the other candidate is the 2018 SRAM chip but in my experience its 95% the Z80 and only 5% bad SRAM.
 
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Congrats on the new game Lazerhawk.
It's ironic how there's all of a sudden a bunch of SFII boards with no sound popping up now.
What's up with this site and trends?
 
Just got the board out and apart tonight and it is a zilog. Looked up the part number and its a blinding 4mhz clock does that sound right? Looking at buying it here if this is the correct one. http://www.mikesarcade.com/cgi-bin/store.pl?sku=Z80ACPU

I bought about 6 of them and 6 of the z80's. They sent me a joy stick for a Donkey Kong. My order was worth about $40 including shipping. The joy stick was worth about $65 alone.

They were very nice and prompt about fixing the order :)

I would buy more that one as the shipping will be $7.40 I think. I bought my 12 to fix the Galaga boards and Mortal Kombat. I think my Dig Dug boards take the same chip but I will have to open the box it came in to see.

Anymore, if I see a Zlog z80 chip I just replace it.

The z80a chip is the one you want and what they sent me was a

Sharp LH0080A Z80A-CPU-D
0418-5B

They work just fine but you may have to replace them 30 years from now.
 
I HAVE FAILED ME FOR THE LAST TIME! *choke self with the force*

Well Ive made matters worse by 100% lol. I replaced the zilog and now I have no sound at all. Every thing went smoothly, or at least I thought. I cut the legs off the zilog popped out the legs with the iron and tweezers. Sucked the solder out with a pump. Put the new chip in facing the same way as the old. Soldered the legs from the backside etc. No joy :( Oh well I guess ill keep my eye out for another board.
 
Well Ive made matters worse by 100% lol. I replaced the zilog and now I have no sound at all. Every thing went smoothly, or at least I thought. I cut the legs off the zilog popped out the legs with the iron and tweezers. Sucked the solder out with a pump. Put the new chip in facing the same way as the old. Soldered the legs from the backside etc. No joy :( Oh well I guess ill keep my eye out for another board.

you need to check the top of feed through holes for shorts and when I do mine I will be putting in a socket.
 
Thats just daft - it only seems affect some CPS1 A boards and the "if it any broke don't fix it" rule still applies.

Every single Galaga board that I have worked on that had the Zilog chips in them seem to work. After a short time they fail. It may very well be that the z80 chips are old but THEY FAIL. The Galaga machines in Crab Town probably have zilog chips as they are always in some kind of FAIL mode. The latest had screen flipped and star field moving very fast. It was the one without the green t-molding just in case someone was wondering.

There is another post where I have read, can't remember now, but it stated over 90% of the sound errors on them there boards was a direct result of the z80 chip failure. It may not be a 100% failure but it is not working all of the time. These chips IMHO are just failing and may not be junk as I suspect.

http://forums.arcade-museum.com/showthread.php?t=5807&highlight=street+fighter+z80

check out post #8 in this link

and your own words, Womble, in post #5 of this link

http://forums.arcade-museum.com/showthread.php?t=197066&highlight=street+fighter+sound
 
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Zilog is THE company who designed the Z80 cou afaik. All others are basically copies from other manufactuers. Not that I have seen any specific problems with any of them but I would definitly trust the Zilog brand.
 
you need to check the top of feed through holes for shorts and when I do mine I will be putting in a socket.

Ive only done this once before and I used a socket. It was for a Mitsubishi ECU and it looked like hell when I was finished but it worked. How do you check for shorts?
 
There is another post where I have read, can't remember now, but it stated over 90% of the sound errors on them there boards was a direct result of the z80 chip failure.

I am aware of that statement, because I was the one who made it. What I am saying is that replacing Zilog Z80s on sight is daft, especially if the board is not faulty. The mass death of these CPUs only seems to affect CPS1 A boards in my experience. I have had many boards in my collection with their original Zilog Z80 chips intact and working.

I have also come across dead Z80s from Sharp, Goldstar and NEC on a variety of boards and there seems to be no mass extinction going on except for the Zilog chips on CPS1 A boards. This may well be due to their location near the edge of the board where the boards are handled thereby exposing them to static damage, in much the same way that mask ROMs located on the edge of boards seem more likely to die than ones well away from the edge. As for Galaga, I have never seen a board with Zilog chips on it, all the ones I have ever seen have NEC Z80s and a couple of those have indeed been dead. It is not inconceivable that the other problem afflicting Galagas (ie bad sockets and resistor networks) put extra strain on the line drivers within the CPU and expedite their demise.
 
As for Galaga, I have never seen a board with Zilog chips on it, all the ones I have ever seen have NEC Z80s and a couple of those have indeed been dead. It is not inconceivable that the other problem afflicting Galagas (ie bad sockets and resistor networks) put extra strain on the line drivers within the CPU and expedite their demise.

I have one here that has nothing but Zilog chips for the cpu chips and have tested them z80s in a working Galaga. They do work for about 5 min. then grafix errors, screen flips, and board locks up solid. Only one of the cpu chips seemed to work the z80a and it does work in any (newer) socket I put it in. I suspect that it is just old age.

It just seems to me the chips are a bit different. They seem to be thinner and closer to the board and possibly not cooling right. I have spent quite a bit of time ferreting out problems with one particular set of boards and found it to be the z80 chip(s) 4j and or 4e. I might just be a bit upset that this took me too long to find but for now I will NOT be ordering any Zilog chips.
 
If your replace your chips on sight you might end up like me :) Actually you probably know what your doing so disregard that lol
 
If your replace your chips on sight you might end up like me :) Actually you probably know what your doing so disregard that lol

You just need a good soldering iron and a bit of expierence. With a bit of practice you will get much better. Just take your time and read/watch u-tube videos about soldering.

If you think there is a solder short just ohm out each of the pins on the chip or socket. You should not get two adjacent pins with a zero ohm reading. If you do you may have a short. Something like a solder blob under the socket or chip. If you need help, just let me know.

My board is having the same problem and I have removed the z80 chip first thing. When I get another socket for the cpu chip I will put that in and then test it.
 
If a new Z80 doesnt wake it up then the next candidate for shotgunning would be the SRAM chip just north of the Z80. If that is not the issue then its back to troubleshooting the audio generation section which is not easy without a scope.
 
I dont think I would get further into troubleshooting until Im able to reproduce the original issue after replacing my z80. Right now, after the new chip, I have zero sound. Before I had sound some of the time so Ive made the issue worse. Im going to check for continuity between pins right now maybe I can find the problem
 
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