Street Fighter II no sound

kb0jjn

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I have recently bought a street fighter II pcb with no sound. I should be getting the board today and I am wondering what to look for. This is listed as working with no sound so we will see.

http://cgi.ebay.com/ws/eBayISAPI.dl...eName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I am thinking sound amp or caps.

This was cheep enough I can throw some money at it to get it going.

I have no manual/schematics/pin outs for this game. Any info is excellent.
 
The sound CPU is on the A board and the connector right next to it carries the data and address busses along with a few other traces to the sound program ROMs on the B board. It also carries the address/data busses for the OKI sound chips to access the 2 sound sample ROMs on the B board.

It's pretty common for those ROMs to get beat up or traces gouged as CPS1 boards tend to get tossed around piles a lot. Also, if you have damaged pins on the A board the signals just will never make it to the B board.
 
If the board has no signs of damage then I would go straight to replacing the Z80 CPU on the lower board. I have fixed literally dozens of CPS1 boards that had no sound and all except one had a bad Z80 as the sole cause. The odd one out was really odd in the fact it had never had a heatsink on the amplifier chip and over the years all the pins on the amp chip had cracked through lack of physical support.

http://retrocomputermuseum.co.uk/forum/index.php?topic=3521.0

You can test the Amp chip by turning the volume pot up and down, if you hear a crackle or hiss that you can change the volume of then the amp and associated caps are healthy. If you hear nothing then press hard with your finger on the pins of the amp chip on the underside of the PCB (take any metal rings or watches off first), this should get you an angry buzzing noise, if you can change the volume of that with the pot then the amp is fine.

Z80s are a very common failure on these, some rumours say they used slower Z80s and drove them faster than they were designed for, but on the ones I fixed the Z80s were marked correctly. One thing I will say is that 100% of the bad Z80s I removed were Zilog brand which seemed to be the standard on the slightly smaller modern version of the CPS1 board which is the most common board seen in the wild these days, the board in the link above is the older longer style CPS1 A board and I haven't seen one of those that used a Zilog Z80.
 
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The sound CPU is on the A board and the connector right next to it carries the data and address busses along with a few other traces to the sound program ROMs on the B board. It also carries the address/data busses for the OKI sound chips to access the 2 sound sample ROMs on the B board.

It's pretty common for those ROMs to get beat up or traces gouged as CPS1 boards tend to get tossed around piles a lot. Also, if you have damaged pins on the A board the signals just will never make it to the B board.

Yes, This guy did NOT pack it very well AT ALL. It came inside a usps box just about the same size as the board and marque (rolled up in a tube), and the only paking material that was used was a single newspaper wrapping the boards. Ok I may be wrong, might have been 2 sheets of newspaper.

I am just glad the boards/box did not get crushed. I am thinking of putting something in the feedback like "Packing Lacking". I always give + feedback as long as I get the item but this should have been packed MUCH better.
 
If the board has no signs of damage then I would go straight to replacing the Z80 CPU on the lower board. I have fixed literally dozens of CPS1 boards that had no sound and all except one had a bad Z80 as the sole cause. The odd one out was really odd in the fact it had never had a heatsink on the amplifier chip and over the years all the pins on the amp chip had cracked through lack of physical support.

http://retrocomputermuseum.co.uk/forum/index.php?topic=3521.0

You can test the Amp chip by turning the volume pot up and down, if you hear a crackle or hiss that you can change the volume of then the amp and associated caps are healthy. If you hear nothing then press hard with your finger on the pins of the amp chip on the underside of the PCB (take any metal rings or watches off first), this should get you an angry buzzing noise, if you can change the volume of that with the pot then the amp is fine.

Z80s are a very common failure on these, some rumours say they used slower Z80s and drove them faster than they were designed for, but on the ones I fixed the Z80s were marked correctly. One thing I will say is that 100% of the bad Z80s I removed were Zilog brand which seemed to be the standard on the slightly smaller modern version of the CPS1 board which is the most common board seen in the wild these days, the board in the link above is the older longer style CPS1 A board and I haven't seen one of those that used a Zilog Z80.

After reading this I just went ahead a ripped that thing out like it was a bad tooth. I did not even put power to thing! What I need now is the schematics for this board or a link to them. It is a street fighter II turbo <<<and I am not sure what that means.
 
Not to thread jack, but what does this issue seem to be?
A CPS1 game will start up but lose sound a few seconds into the attract tune.

My guess is bad caps. After every reset the sound will come back momentarily.
 
I did not even put power to thing!

That was an extremely bad idea, now you have no idea if the board even worked before you started on it. You ALWAYS need to assume the seller has no idea and has diagnosed it wrongly, he could have assumed it had no sound as his 12V feed on the PSU was dead. You also don't know if "no sound" really was no sound, it could have been very quiet, or only there in bursts.

There are no schematics for these boards, obviously there were once but then never escaped into the wild and are now lost to history.

Why would you need schematics if you are just replacing a single chip. Unless you literally hacked the shite out of the board to get it out you should just solder the new one in.
 
That was an extremely bad idea, now you have no idea if the board even worked before you started on it. You ALWAYS need to assume the seller has no idea and has diagnosed it wrongly, he could have assumed it had no sound as his 12V feed on the PSU was dead. You also don't know if "no sound" really was no sound, it could have been very quiet, or only there in bursts.

There are no schematics for these boards, obviously there were once but then never escaped into the wild and are now lost to history.

Why would you need schematics if you are just replacing a single chip. Unless you literally hacked the shite out of the board to get it out you should just solder the new one in.

This is quite true.

My brother thought his speakers blew out one time on his cab. I credited the game, hit start. Then just opened the CP and turned the little white cap and watched his face light up when the sound faded in. :D

I've also heard of people buying games that "had no sound" for dirt cheap. Come to find that the volume dial was all the way off. Since the dials are not always obvious, people over look them.

@channelmanic Thanks for the info. I learned something new about these boards.
 
Well it may be true I should have power it up but I have had nothing but problems with the zlog chips. My galaga works with the nec chips but if I put in a zlog chip it will work then die. From looking at the other auctions this guy had he was selling about 3 of the same boards at the time so I am thinking he had a good way to test them.

Also my power supply is not a good one. It is a computer power supply and the +5 is a bit low. Something like 4.88 and 4.85 at the chips. The farthest part of the board has 4.83 on the chips.

I have an order for about 12 z80 cpu chips and a power supply. It is a newer board so desoldering was very easy. I am just waiting on parts so it gave me something to do other than clean the shop.

As far as the zlog chips it does not matter what they are z80a, z80b, z80, they just don't seem to work in the Galaga board set. Other logs show this chip is ify at best. The chip is not costly so it would be an easy fix. I will probably put in a socket so I can test other chips and see which chips work and don't.

If it was not the chip then I will have a good base for testing. I expect that when I put in the new chip I will have sound but time will tell and I will let you all know.
 
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Sorry to drag up an old post
I have an A board with no sound
I recapped to start off with
But still nothing.
I get static when adjusting the pot so i believe the amp is ok

Next ill remove the Z80 and put a socket and new chip

Will report back.

Ps
How did you guys get on ?

Dave
 
If the board has no signs of damage then I would go straight to replacing the Z80 CPU on the lower board. I have fixed literally dozens of CPS1 boards that had no sound and all except one had a bad Z80 as the sole cause. The odd one out was really odd in the fact it had never had a heatsink on the amplifier chip and over the years all the pins on the amp chip had cracked through lack of physical support.

http://retrocomputermuseum.co.uk/forum/index.php?topic=3521.0

You can test the Amp chip by turning the volume pot up and down, if you hear a crackle or hiss that you can change the volume of then the amp and associated caps are healthy. If you hear nothing then press hard with your finger on the pins of the amp chip on the underside of the PCB (take any metal rings or watches off first), this should get you an angry buzzing noise, if you can change the volume of that with the pot then the amp is fine.

Z80s are a very common failure on these, some rumours say they used slower Z80s and drove them faster than they were designed for, but on the ones I fixed the Z80s were marked correctly. One thing I will say is that 100% of the bad Z80s I removed were Zilog brand which seemed to be the standard on the slightly smaller modern version of the CPS1 board which is the most common board seen in the wild these days, the board in the link above is the older longer style CPS1 A board and I haven't seen one of those that used a Zilog Z80.
Thanks, the new Z80 fixed my sound issue.
 
I had an A board with no sound a few months ago, Backbit tester ultimately confirmed that the 6116 sound ram and Z80 were both bad.
 
Nice fix, Yorge!
I neglected to mention I piggybacked the 6116 ram and got sound once, but then it quit working. that essentially told me the ram was bad though. which the Backbit confirmed. I had socketed/replaced the Z80 something like 2~ months prior and that had no change. I still had the Z80 out sitting on my PC-10 and for giggles decided to test it, it was bad.

the A board was missing the whole interconnect by the sound section, I just robbed one off one of my bad graphics A boards from a Final Fight years ago.
 
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