SF2 World Warrior A board - sound cutting out

PCB problems and fixes
Forum rules
ArcadeOtaku forum introduction & rules
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 10th, 2017, 4:36 am

Hey guys, anyone seen this problem before?

I"ve isloated it to the A board. The board will start up fine and play fine for an indeterminate amount of time. Sometimes it's 5 minutes, sometimes it's 15 minutes. One time I left it on for about 40 minutes, with no problem. On average, and every time but that once, I would say sound cuts out around 5 minutes. The game continues to play "deaf".

It makes a scratchy noise when cutting out, and then audio is gone.

I've replace the Z80, amp and caps in the audio circuit.

Next suggestions?
User avatar
Bytestorm
Posts: 23
Joined: July 20th, 2012, 1:53 pm
Aliases: bytestorm
eBay: stefan_nafets
Initials: LSN
Location: Sweden / Skövde

Re: SF2 World Warrior A board - sound cutting out

Postby Bytestorm » February 10th, 2017, 8:08 pm

NoAffinity wrote:Hey guys, anyone seen this problem before?

I"ve isloated it to the A board. The board will start up fine and play fine for an indeterminate amount of time. Sometimes it's 5 minutes, sometimes it's 15 minutes. One time I left it on for about 40 minutes, with no problem. On average, and every time but that once, I would say sound cuts out around 5 minutes. The game continues to play "deaf".

It makes a scratchy noise when cutting out, and then audio is gone.

I've replace the Z80, amp and caps in the audio circuit.

Next suggestions?


I had the same problem on 2 A boards.. check the clock to the z80 when the sound cuts out. If I remember correctly it lost clocksignal after 1-15 minutes randomly playing perfect.. cant find the log now check pin 6 with a scope of logic probe.
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 10th, 2017, 8:47 pm

Bytestorm wrote:
NoAffinity wrote:Hey guys, anyone seen this problem before?

I"ve isloated it to the A board. The board will start up fine and play fine for an indeterminate amount of time. Sometimes it's 5 minutes, sometimes it's 15 minutes. One time I left it on for about 40 minutes, with no problem. On average, and every time but that once, I would say sound cuts out around 5 minutes. The game continues to play "deaf".

It makes a scratchy noise when cutting out, and then audio is gone.

I've replace the Z80, amp and caps in the audio circuit.

Next suggestions?


I had the same problem on 2 A boards.. check the clock to the z80 when the sound cuts out. If I remember correctly it lost clocksignal after 1-15 minutes randomly playing perfect.. cant find the log now check pin 6 with a scope of logic probe.

Thanks, Bytestorm. I will check with a logic probe. Do you recall what the fix was (or were you able to fix it)?
User avatar
Bytestorm
Posts: 23
Joined: July 20th, 2012, 1:53 pm
Aliases: bytestorm
eBay: stefan_nafets
Initials: LSN
Location: Sweden / Skövde

Re: SF2 World Warrior A board - sound cutting out

Postby Bytestorm » February 10th, 2017, 8:52 pm

NoAffinity wrote:
Bytestorm wrote:
NoAffinity wrote:Hey guys, anyone seen this problem before?

I"ve isloated it to the A board. The board will start up fine and play fine for an indeterminate amount of time. Sometimes it's 5 minutes, sometimes it's 15 minutes. One time I left it on for about 40 minutes, with no problem. On average, and every time but that once, I would say sound cuts out around 5 minutes. The game continues to play "deaf".

It makes a scratchy noise when cutting out, and then audio is gone.

I've replace the Z80, amp and caps in the audio circuit.

Next suggestions?


I had the same problem on 2 A boards.. check the clock to the z80 when the sound cuts out. If I remember correctly it lost clocksignal after 1-15 minutes randomly playing perfect.. cant find the log now check pin 6 with a scope of logic probe.

Thanks, Bytestorm. I will check with a logic probe. Do you recall what the fix was (or were you able to fix it)?


I dont have any cps1 a board any more but I recall I changed a 74xxxx in between the z80 and the crystal.. I think I have a schematic of the A board somewhere..
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 11th, 2017, 7:23 am

Checked pin 6 with a logic probe before and after sound is lost. Same result: Logic “0”, with positive single pulse
User avatar
Bytestorm
Posts: 23
Joined: July 20th, 2012, 1:53 pm
Aliases: bytestorm
eBay: stefan_nafets
Initials: LSN
Location: Sweden / Skövde

Re: SF2 World Warrior A board - sound cutting out

Postby Bytestorm » February 11th, 2017, 10:27 am

When the sound cuts out, do you still get higher / lower "hissing" from the amp if raising the volume?
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 11th, 2017, 5:11 pm

One thing you can do with a oscilloscope is check if the YM2151 is still generating interrupts when the sound stops. That would give you a good idea if the digital circuitry is still running or if the sound stopped because it crashed. If the Z80 is crashing, changing caps won't make the sound work any better... :awe:
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 11th, 2017, 5:48 pm

leonardoliveira wrote:One thing you can do with a oscilloscope is check if the YM2151 is still generating interrupts when the sound stops. That would give you a good idea if the digital circuitry is still running or if the sound stopped because it crashed. If the Z80 is crashing, changing caps won't make the sound work any better... :awe:

Regarding the question about hissing, do you mean hissing through the speakers? Intermittently there is a little crackle/staticky noise, after sound is lost and I let the game keep running. One time and one time only, the last tone kept playing, slowly progressing through different tones. I don't know how frequently the tone was changing, but I'd say it was maybe in 4-5 second intervals.

Unfortunately, I haven't yet shelled out for a scope. Can I check the YM2151 with the logic probe?

I replaced the z80 and understand that replacing caps won't improve an upstream problem. Admittedly it's been a shotgun approach, but would like to take a more informed approach before replacing anything else. Would the z80 crashing be caused by some other component, or strictly a problem at the z80?
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 12th, 2017, 12:54 am

Well you can check with a probe sure, what you need to know is if the interrupt pin on the YM2151 is pulsing. The timer on YM2151 is what synchronizes the music tempo and without it, the Z80 won't execute any instructions on the music driver. It will stay idle looping at a portion of the driver code waiting for the timer tick.

About the shotgun approach I wasn't criticizing it as you would end having to replace them at some point in the future anyway.
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 12th, 2017, 1:51 am

Thanks, mate, will check these things. And no worries, I wasn't taking it as criticism. If anything, I was being critical of myself. :cry: I've had a few lucky successes with repairs, but admittedly want to have a deeper understanding so I'm not shotgunning. Thanks for taking the time with someone who's humbly learning. :)
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 12th, 2017, 7:29 pm

I think we're getting somewhere now. Probing pin 2 (IRQ) of the YM2151 while sound is working produces pulsing - Logic “1”, with negative single pulses.

When sound crapped out, the signal goes high, with no pulsing (solid). But then when removing the probe, sound returns. Sound has never returned prior to this.

Sound crapped out again a couple minutes later, and I probed again. Same result - signal high with no pulse, sound returned when removing the probe. I immediately probed it again with the sound working, and the probe is all over the board. High-low spasms, pulsing/non-pulsing, audio is scratchy. Then removing the probe, there is only action sounds with no music. Music returned about 20 seconds later.

Time to replace the YM2151, or is it something deeper in the circuit?
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 13th, 2017, 3:23 am

IRQ is driven on YM2151 as an "open collector" signal. Means the pin on YM2151 draws current to bring the line to logic level 0 when it want to flag an interrupt.

For that to work we have a high value (usually 4700 ~ 10000 ohms resistor supplying the IRQ line with +5v bias so it stays at logic level1. Try putting a 10k resistor from pin 2 to pin 22 at the under side of the board, for a test. If that fixes your board, the SMD resistor at position "R52" near the Z80 is to blame.

If that fiddling with the resistor don't help there might be a problem with the YM2151 timer portion.
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 13th, 2017, 5:39 am

I pulled R52 and measured its resistance. It is labeled "472" and measured at 4.7k. I buggered that one trying to solder it back on (not much experience with SMD desoldering/soldering yet :cry: ). I pulled R52 off a CPS DASH parts A board, also labeled "472". Measured it, and it is at 4.68k. I soldered that one back on without incident and waited for sound to fail, which it did.

Are there things to check with the YM2151 timer portion, or is that a problem internal to the YM2151?
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 13th, 2017, 4:57 pm

have you measured the trace from the Z80 pin to the YM2151?

If everything is fine outside, the problem will be internal to the YM2151... Perhaps the bonding wire from the YM2151 die to the IC package pin is starting to fail.

I have a original YM2151 which came from a dead System 16 board. It has three dead pins (/RD /WE /CS) and because of that it can never receive CPU commands. So it's as good as trash.
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 13th, 2017, 6:08 pm

leonardoliveira wrote:have you measured the trace from the Z80 pin to the YM2151?

If everything is fine outside, the problem will be internal to the YM2151... Perhaps the bonding wire from the YM2151 die to the IC package pin is starting to fail.

I have a original YM2151 which came from a dead System 16 board. It has three dead pins (/RD /WE /CS) and because of that it can never receive CPU commands. So it's as good as trash.

I haven't measured the trace. A simple continuity test, or something more complex?

Interesting stuff, thanks for all the help here. Seems we're getting close.
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 15th, 2017, 5:56 am

So, I came back across the CPS1 repair logs on the wiki here, and decided to start from square one, following the Troubleshooting CPS 1 audio problems (http://wiki.arcadeotaku.com/w/CPS1_Repair_Logs, scroll down). Below is what I'm getting.

YM2151
• Pin 2 (IRQ)- Logic “0”, no pulse activity.
• Pin 4 (address) - Logic “1”, no pulse activity.
• Pin 5 (WR*) - Logic “1”, no pulse activity.
• Pin 6 (RD*) - Logic “1”, no pulse activity.
• Pins 10, 12, 13-18 (Data) - nothing
• Pin 21 - steady pulse (no audio coming out)
EPROM 9
• Nothing on the data lines
YM3012
• Nothing on lines 9-15

The next suggestion is to "replace the CPU". Is that referring to the z80?

Assuming so, I've already done that, and the next suggestions is replace "the SRAM IC. (2k x 8 - a 6116 SRAM IC can be used to replace it)". Probably completely noobish of me, but where is the SRAM IC? I can't find any reference to what/where it is on the board.
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 15th, 2017, 1:26 pm

Man, it's the YM2151 timer which makes the CPU walk through the song, as I explained before using other wording...

If the YM2151 stops pulsing it's IRQ, the CPU will sit idle even if it's working properly. The YM2151 will hold the IRQ line low until the Z80 "services" the IRQ. Means the YM2151 requests attention from the Z80 by pulling the line low but it's an action from the Z80 writing to the timer registers which sets it again for the next cycle. That will release the IRQ pin on the YM2151. The Z80 is supposed to set the timer again and perform another "frame" of music playback processing, then sit idle on a loop waiting for the next interrupt. That should happen periodically and that's how it maintains the music "tempo" through the processing. Edit: If something else disturbs and freezes the Z80 this cycle will stop, as well.


YM3012 has nothing to do with this stuff. It converts digital stream output by YM2151 to analog. You would have no YM2151 audio at all if there were a issue with it (but you would have drums, voices and sound effects).

I think you're on the right path testing the Z80 RAM next. (marked: I4F TMM2015-15)
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 15th, 2017, 4:10 pm

Ok thank you. I'm slowly getting a grasp of the bigger picture while working through the steps. Interestingly, one time when sound returned while I was probing, voices and attack sounds (possibly drum sounds too) came back about 5 seconds before music. That seems to add to the evidence that theres no need to look at the y3012.

Thanks for id'ing the sram ic. Will check that tonight. What should I be looking for at the sram?
User avatar
leonardoliveira
Posts: 493
Joined: August 30th, 2012, 5:53 am
Initials: leo
Location: Brazil

Re: SF2 World Warrior A board - sound cutting out

Postby leonardoliveira » February 15th, 2017, 5:46 pm

Only way is removing it and testing it at an IC tester which can test SRAM. Or you can just swap it out with a known good chip. It's your regular vanilla 6116 2KB 8bit SRAM.
Image
User avatar
NoAffinity
Posts: 184
Joined: January 8th, 2017, 3:46 pm
eBay: noaffinity
Gamertag: YesAffinity
Initials: CSG
Location: Escondido, CA, USA
Contact:

Re: SF2 World Warrior A board - sound cutting out

Postby NoAffinity » February 15th, 2017, 9:46 pm

All right, i ordered a replacement. Didn't want to pull a working one and don't want to take my chances from a parts board. $3 shipped seemed like good insurance for a new replacement.

The one I ordered is 90ns. I assume the part number above, -15, is 150 ns? I couldn't find a good dataset for that part number.

Return to “Game Hardware Q&A”



Who is online

Users browsing this forum: No registered users