Ikari Warriors - No Sound

grantopia

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Picked this up off CL today with no sound coming out. Volume adjustments on the board don't seem to do anything. I have the manual, but it doesn't break down the chips on the board so I'm not sure what to reseat (if anything) to start. The connection to the speaker looks good. There's what looks like an interface board between the PCB and the harness. I was wondering if maybe my voltage could be too high (or low?)? Everything but the sound is working as it should and I don't get any errors in test mode.

Unfortunately my picture uploads keep failing, but I wanted to put it out there to see if anyone had any ideas - thanks!
 
Pictures of the board stack, boards, and interface board. All voltages are measuring fine at the PCB edge connector. I can't for the life of me find a schematic to even begin to determine where the audio section of this thing is. Could the volume pots be back somehow? The speaker? Any help or ideas out there?









 
Ikari Warriors runs -5V on sound.
Is your arcade wired for -V5 on the sound?

I run a -5V adapter on my Ikari warriors to jamma adapter.
 
Ikari Warriors runs -5V on sound.
Is your arcade wired for -V5 on the sound?

I run a -5V adapter on my Ikari warriors to jamma adapter.

Honestly, I have no idea! I'm getting -5V at the board (which sounds different than what you're saying here). How would I go about checking this?
 
Honestly, I have no idea! I'm getting -5V at the board (which sounds different than what you're saying here). How would I go about checking this?

I believe Biomech has a JAMMA adapter for his Ikari PCB and he runs -5V to the adapter, so his Ikari PCB gets a -5V.

Sounds like you have -5V on the board though. Have you checked the amp chip, is that getting hot, what happens if you turn the volume up/dow, is there any sound at all? I would pull out the specs of the amp chip and see if it is getting the right voltage.

paris
 
I believe Biomech has a JAMMA adapter for his Ikari PCB and he runs -5V to the adapter, so his Ikari PCB gets a -5V.

Sounds like you have -5V on the board though. Have you checked the amp chip, is that getting hot, what happens if you turn the volume up/dow, is there any sound at all? I would pull out the specs of the amp chip and see if it is getting the right voltage.

paris

I am getting -5v on the PCB, which it sounds like its a good thing. Unfortunately I don't have a diagram that I can find to indicate which chip(s) are related to the audio or find where the amp is. Do you happen to know which ones they are or have you seen a schematic floating around out there for these boards? If I mess with the pots on the board for volume nothing happens...no speaker crackle or anything at all.
 
The Amp is the one next to the volume pots, looks like a fat "T", I believe it has 10 pins. It is screwed onto the pcb.

Does that get hot? Sometimes running your finger across the pins will cause some interference that is audible, i.e. the chip is outputting signal.
 
The Amp is the one next to the volume pots, looks like a fat "T", I believe it has 10 pins. It is screwed onto the pcb.

Does that get hot? Sometimes running your finger across the pins will cause some interference that is audible, i.e. the chip is outputting signal.

Here's the chip:



It doesn't really feel hot, maybe a little warm, but that could be the mental effect of me feeling for it to be hot :). I don't get any sounds or feedback when touching the pins. Do you know how to test these to see if the right voltage is at the chip or if its bad? I guess it could be the actual speaker but I don't have anything to swap with to test. Are there other sound chips on the board to reseat or check?
 
Could be a number of things at fault, the z80 sound cpu, the YM3526 sound chip, the sound ram, the sound rom, before the signal reaches the amp. Can you check the ROMs and do you have a logic probe?
 
Could be a number of things at fault, the z80 sound cpu, the YM3526 sound chip, the sound ram, the sound rom, before the signal reaches the amp. Can you check the ROMs and do you have a logic probe?

This is very helpful that someone knows where these are! Do you have a board schematic you could send me or are you just familiar with it? Either way, it sounds like once I can figure out where those chips are I need to check them out. Is the best way to start by looking to see if they are getting the right voltages (and seated correctly)? If so I'll need to figure out what pins should be getting what. I'm not sure what you mean by check the ROMs, I did run a self-test in the service menu and didn't get any errors.

I don't have a logic probe (yet). I was actually (very slowly) learning about them online watching some tutorials before this game was on my radar to get, so it was just kind of by chance I picked it up. I'm not opposed to getting one at all (and will soon) but I figured I could rule out all the "obvious" checks first before diving into that. Anything you have on this would be much appreciated!
 
Sorry, I don't have a schematic but all these chips are located very close to the volume pots. I believe the two ROMs (with labels) close to the pots are sound ROMs. If ROM test passes, they're probably good, but if you had an EPROM reader, that would verify the code in them.

The Z80 CPU for sound is also in the vicinity of the volume pots, but I am not sure which of the three Z80s on this PCB it is. Without a logic probe, there is little to do except check for voltages on the GND and 5V (you can get the pinouts through a google search). If the CPUs on this PCB are socketed, you could exchange with known working Z80s and see if the problem persists. As a matter of fact, and again if the chips are socketed, you can move those three Z80s around the same PCB and see if other problems arise. For example, if the sound Z80 has issues and you place it in the socket for the game code running Z80, the game would probably not work. That would confirm a bad Z80.

The sound chips YMxxx are also in the vicinity of the volume pots. The pinouts are out there, you can check for voltages, but again, without a logic probe, it is hard to know what is going on.

The problem with this PCB might be simple, but figuring out what it is may involve time and some additional equipment purchases. At this stage, I would think about that and how comfortable you are in terms of devoting time, effort and money. It may be easier to either send this for repair or getting a known working one... this is a "fairly" easy to find PCB so perhaps the repair costs would be more than a completely new purchase. There are threads on who repairs what on the front page of the this forum category.

If, on the other hand, you are interested in repairs, then the extra equipment purchases may not be a bad idea...

My 2c..., sorry I could not be of any other help...

paris
 
Sorry, I don't have a schematic but all these chips are located very close to the volume pots. I believe the two ROMs (with labels) close to the pots are sound ROMs. If ROM test passes, they're probably good, but if you had an EPROM reader, that would verify the code in them.

The Z80 CPU for sound is also in the vicinity of the volume pots, but I am not sure which of the three Z80s on this PCB it is. Without a logic probe, there is little to do except check for voltages on the GND and 5V (you can get the pinouts through a google search). If the CPUs on this PCB are socketed, you could exchange with known working Z80s and see if the problem persists. As a matter of fact, and again if the chips are socketed, you can move those three Z80s around the same PCB and see if other problems arise. For example, if the sound Z80 has issues and you place it in the socket for the game code running Z80, the game would probably not work. That would confirm a bad Z80.

The sound chips YMxxx are also in the vicinity of the volume pots. The pinouts are out there, you can check for voltages, but again, without a logic probe, it is hard to know what is going on.

The problem with this PCB might be simple, but figuring out what it is may involve time and some additional equipment purchases. At this stage, I would think about that and how comfortable you are in terms of devoting time, effort and money. It may be easier to either send this for repair or getting a known working one... this is a "fairly" easy to find PCB so perhaps the repair costs would be more than a completely new purchase. There are threads on who repairs what on the front page of the this forum category.

If, on the other hand, you are interested in repairs, then the extra equipment purchases may not be a bad idea...

My 2c..., sorry I could not be of any other help...

paris

Thanks for the additional information. I am definitely trying to learn more about repair, so sending it out or getting a new board would be my last resort if I keep the game as I'd like to learn by doing and try and teach myself in the process. I was debating getting a logic probe, but the struggle with this game is that once I get it, I still need some diagrams that I can't seem to find, and presumably help interpreting them as to what I should be seeing for readings, which was why my initial plan was to start with the chips themselves and see if anything looks bad there. I'll take a look at any identification marks on the chips near the volume pots and see what I can find about them and try some testing there first and report back.
 
Sounds like a plan. FYI, the logic probe is a $20 purchase, I have found it valuable in troubleshooting. I am by no means an expert (although I have a few repairs under my belt) but I think it is a worthy purchase.

paris
 
Before jumping into PCB repair, Id check continuity from the Ikari PCB speaker outs to the speakers. You'll want to unplug the wires from the speakers first and run the tests with all power off. This way you can eliminate the connections, the adapter and its pinouts and wiring from the equation. Mikesarcade has the pinout for the board on his site. Just a thought...
 
Before jumping into PCB repair, Id check continuity from the Ikari PCB speaker outs to the speakers. You'll want to unplug the wires from the speakers first and run the tests with all power off. This way you can eliminate the connections, the adapter and its pinouts and wiring from the equation. Mikesarcade has the pinout for the board on his site. Just a thought...

Someone mentioned to me to check the resistance at the connector as well for the speakers, which sounds different than what you're saying, but I should probably check both of these out. Are there any good how to guides out there for both of these checks (where to put probes, etc? never had to do it before). I'll poke around on google and see what I can find today.
 
Maybe I'm too optimistic here, but I may be on to something. I tested the resistance at the speaker itself at it looks like the speaker itself is good. I went to test at the edge connector, and upon removing the connector, I noticed that one of the pins (forth from right on top row) was severely corroded like a blue/green color (it was worse before I thought to snap a picture). Per the manual, this also looks like my speaker + pin on the connector. Of course, upon trying to chip off the stuff, I managed to fully crack the pin. I'm now determined to get sound back on this thing, so my questions are:

1. If this pin was corroded to the point it wasn't making contact with the PCB at the edge connector, (speaker - looked clean), would that have potentially caused no audio at all

2. Instead of replacing the connector right away, can I just run a jumper from the small interface board to the main PCB to test this theory and bypass the formerly corroded and now broken pin within the connector?

Please toss out any thoughts! Thanks!
 

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yes on both accounts! id say you are definitely on to something!
 
Had a lot of actual house projects the past week, so finally have some time to get back to this! Here's where I'm at...I think I can run a jumper wire from the interface board to the pcb and bypass that corroded/broken pin in the connector. My question there is (as I've never done this before) do I solder the wire at the edge of the interface board and then to the back of the pcb, following the trace from the edge connector to when it stops (if that makes sense, yikes...)?

I also was reading about checking resistance at the volume pot to rule that out...should I take a look at that as well? Presumably with the game on?
 
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