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To all those that know the JP SMS Mk-2000 well, I have a very annoying issue that no one else can seem to solve.

Imported this particular console straight from Japan and the owner seems to have made a few modifications - including using a soldering iron to burn through the case, but that's irrelevant.

The main issue is that the previous owner soldered wires on the 8-pin LM 358N amplifier chip. The person used R27 as a ground with the wire shielding. Obviously, I've now removed this mod.

So, now my SMS Mk-2000, the FM Sound has static on one of the sound channels, and it's driving me crazy trying to fix it. It only gets static up on that one single FM channel - so some games have almost no static in them at all.

The best example of the sound issue is that start screen song on Aleste/Power Strike creates static on the melody channel (ie, not the drum/bass channel)

Unfortunately, the solder pad on R27 has been completely lifted (see picture), so no proper connection can be made with the ground.

However I've tried to connect the R27 resistor ground leg to other grounding points on the board, but it seems to make no difference. I've also pulled the resistor out of circuit entirely, and it sounds essentially the exact same. Last, the resistor still gives a proper reading of 3k3 ohms.

I've tried almost everything - can anyone provide advice on where to test next or what the problem could be?

Are one of the sound chips fried? Is it a circuitry issue?

Thanks in advance!

you verified it's a single FM channel that doesn't sound right?
Did you test this with a tool like this one?
I think I wouldn't expect any hardware problem outside the chip to affect one single audio channel...

sverx wrote

you verified it's a single FM channel that doesn't sound right?
Did you test this with a tool like?
I think I wouldn't expect any hardware problem outside the chip to affect one single audio channel...

Ok, that's an amazing tool. Unfortunately, I don't currently have a flash cart for the Master System...although I do have one for the Mega Drive, so maybe I could somehow identify the channel by messing with the sounds on there?

The main two games that really are affected (that I own) are Aleste and Alex Kidd BMX - both of those have static right on the intro screen music and during gameplay.
Again, whatever channel carries the melody it sounds like static.

Is it supposed to sound like that?

The next question would be: how would I go about testing which chip might be faulty? I know there seems to be at least two chips associated with the FM Sound - the actual Yamaha and a controller.

I'm confused how this would even happen in the first place, but any help with testing would be great.

Thank you for your reply!

The weird thing is, the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad. Having said that, I noticed here:

he mentions the same thing (at time 8:30) - after having no issue with YM2413s in two other hardware models. Maybe it’s common?

In a comment (and I know YouTube comments are generally pretty low quality) someone says it’s due to the YM2413’s TDM “mixing” and the SMS lacking the correct low pass filter - but I’m not sure how true that is.

Maxim wrote

The weird thing is, the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad. Having said that, I noticed here:
he mentions the same thing (at time 8:30) - after having no issue with YM2413s in two other hardware models. Maybe it’s common?

In a comment (and I know YouTube comments are generally pretty low quality) someone says it’s due to the YM2413’s TDM “mixing” and the SMS lacking the correct low pass filter - but I’m not sure how true that is.

Yes, I'm beginning to think it might be more common than we may have thought - but now the question is: is this just something that develops over time with all FM Sound on the Mark III/Mk-2000?

And if so, will replacing components and/or chips affect it at all?
I may just buy a new YM2413 and controller to put into the system and see if anything changes.

It really does sound like the sound isn't properly grounded or something of the sort - something that causes a light bit of static.

I found an Aleste OST that sounds pretty much identical to my system, but I can't post links yet, as I'm still new. So clearly, this doesn't seem to be an isolated issue. Maybe I can PM the video link to anyone who is interested - it's from a user named karanba72 with the FM Aleste soundtrack.

I've recapped the system and even tried taking out a resistor from the circuit i thought was causing it. The quality of the static actually did change slightly, but nothing too notable.

I also noticed the solder pads in the Mk-2000 were incredibly fragile and would lift easily. Now I'm wondering if the weakening circuitry has something to do with it.

Thanks to all for your continued help! I think we can get this figured out!

Maxim wrote

the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad

yeah that's why I was asking if he could verify it was really a single channel by using ccovell's tool...

said that, I have no clue on how to help :|

It would be good to get someone with electronics knowledge to confirm if the MK-2000 is lacking the output filtering, and if it’s in the FM Unit and the FM mod.

That Aleste video:

I’m not sure if it’s on real hardware though?

Note that “new” YM2413s may be old ones resurfaced, or even fake. I don’t know if real new ones exist.

Maxim wrote

It would be good to get someone with electronics knowledge to confirm if the MK-2000 is lacking the output filtering, and if it’s in the FM Unit and the FM mod.

That Aleste video:
I’m not sure if it’s on real hardware though?

Note that “new” YM2413s may be old ones resurfaced, or even fake. I don’t know if real new ones exist.

Someone like Tim Worthington or db Electronics would probably be helpful, but I can't bring myself to bother them about these issues.

That video sounds incredibly similar to my system, so I assume that recording is from a real console? All the emulators/external boards usually have crystal clear FM audio now, even if the sound is not quite right.

It seems all the YM2413s on eBay are the same variant. Still wondering if I should try to drop in a new chip or if it'd be pointless, since it seems there could be some other filtering issues at play?

I seem to remember that where there's a filter there's a capacitor...

is that possible that you might try to replace an old capacitor?

unfortunately I can't suggest which one :|

Glimlocker wrote

It seems all the YM2413s on eBay are the same variant. Still wondering if I should try to drop in a new chip or if it'd be pointless, since it seems there could be some other filtering issues at play?

I would try a different ym2413 and see what happens. Solder a socket onto the board though so that you can easily swap chips without having to do any extra soldering and risk more tracks and or pads lifting off the board.

Id gather that any filtering would apply to the whole chip output as all channels are mixed internally, so if the majority of its sound output works fine then its probably the ym2413 itself thats faulty.

It’s supposed to be an artefact of the interaction between the channels and the way it’s not really mixed properly; since the noise seems quite wide spectrum, it’s hard to see how low pass filtering would help though.

Maxim wrote

It’s supposed to be an artefact of the interaction between the channels and the way it’s not really mixed properly; since the noise seems quite wide spectrum, it’s hard to see how low pass filtering would help though.

Ok - so is this actually inherent on all FM Sound modules and Mk-2000s on the Master System?

If that's true, then I might just hold off on trying to repair/modify it.

It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip.

Maxim wrote

It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip.

Came back to update about this issue.

After originally posting about this specific Master System, I decided to buy another JP Master System in better condition to see if it's any better.

It still has the exact same issue of distortion on the same specific sound channel(s?) - if that makes sense. Essentially the same notes (e.g. the Aleste intro) gives the same effect.

I'm beginning to believe that most JP Master Systems may inherently have this bizarre distortion issue.

Edit: We also have another report of this distortion on this forum that coincidentally came up when I came to update. So, I'm curious how widespread this is.

Just wanted to update everyone, just in case someone out there could take a closer look at the schematics/board and determine what could be the cause.

Glimlocker wrote

Maxim wrote

It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip.

Came back to update about this issue.

After originally posting about this specific Master System, I decided to buy another JP Master System in better condition to see if it's any better.

It still has the exact same issue of distortion on the same specific sound channel(s?) - if that makes sense. Essentially the same notes (e.g. the Aleste intro) gives the same effect.

I'm beginning to believe that most JP Master Systems may inherently have this bizarre distortion issue.

Edit: We also have another report of this distortion on this forum that coincidentally came up when I came to update. So, I'm curious how widespread this is.

Just wanted to update everyone, just in case someone out there could take a closer look at the schematics/board and determine what could be the cause.

Hi !

Does it happen on Mark III with FM module too ?

From my experience yes, it also happens on the FM Sound Unit.

yogi_om wrote

Hi! Does it happen on Mark III with FM module too ?

I unfortunately do not have a Mark III with an FM Module to compare it against.

The issue seems fairly common place - perhaps universal? - on the JP Master Systems, though.

Author	Message
Glimlocker Joined: 25 Mar 2020 Posts: 19	Need some FM Sound enthusiasts - JP SMS FM Sound Issue Posted: Fri Sep 04, 2020 10:05 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	To all those that know the JP SMS Mk-2000 well, I have a very annoying issue that no one else can seem to solve. Imported this particular console straight from Japan and the owner seems to have made a few modifications - including using a soldering iron to burn through the case, but that's irrelevant. The main issue is that the previous owner soldered wires on the 8-pin LM 358N amplifier chip. The person used R27 as a ground with the wire shielding. Obviously, I've now removed this mod. So, now my SMS Mk-2000, the FM Sound has static on one of the sound channels, and it's driving me crazy trying to fix it. It only gets static up on that one single FM channel - so some games have almost no static in them at all. The best example of the sound issue is that start screen song on Aleste/Power Strike creates static on the melody channel (ie, not the drum/bass channel) Unfortunately, the solder pad on R27 has been completely lifted (see picture), so no proper connection can be made with the ground. However I've tried to connect the R27 resistor ground leg to other grounding points on the board, but it seems to make no difference. I've also pulled the resistor out of circuit entirely, and it sounds essentially the exact same. Last, the resistor still gives a proper reading of 3k3 ohms. I've tried almost everything - can anyone provide advice on where to test next or what the problem could be? Are one of the sound chips fried? Is it a circuitry issue? Thanks in advance!

sverx Joined: 05 Sep 2013 Posts: 3828 Location: Stockholm, Sweden	Posted: Sat Sep 05, 2020 7:04 pm
	you verified it's a single FM channel that doesn't sound right? Did you test this with a tool like this one? I think I wouldn't expect any hardware problem outside the chip to affect one single audio channel...

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Tue Sep 08, 2020 6:35 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	sverx wrote you verified it's a single FM channel that doesn't sound right? Did you test this with a tool like? I think I wouldn't expect any hardware problem outside the chip to affect one single audio channel... Ok, that's an amazing tool. Unfortunately, I don't currently have a flash cart for the Master System...although I do have one for the Mega Drive, so maybe I could somehow identify the channel by messing with the sounds on there? The main two games that really are affected (that I own) are Aleste and Alex Kidd BMX - both of those have static right on the intro screen music and during gameplay. Again, whatever channel carries the melody it sounds like static. Is it supposed to sound like that? The next question would be: how would I go about testing which chip might be faulty? I know there seems to be at least two chips associated with the FM Sound - the actual Yamaha and a controller. I'm confused how this would even happen in the first place, but any help with testing would be great. Thank you for your reply!

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14745 Location: London	Posted: Tue Sep 08, 2020 8:50 pm
	The weird thing is, the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad. Having said that, I noticed here: he mentions the same thing (at time 8:30) - after having no issue with YM2413s in two other hardware models. Maybe it’s common? In a comment (and I know YouTube comments are generally pretty low quality) someone says it’s due to the YM2413’s TDM “mixing” and the SMS lacking the correct low pass filter - but I’m not sure how true that is.

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Wed Sep 09, 2020 6:41 am
Glimlocker Joined: 25 Mar 2020 Posts: 19	Maxim wrote The weird thing is, the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad. Having said that, I noticed here: he mentions the same thing (at time 8:30) - after having no issue with YM2413s in two other hardware models. Maybe it’s common? In a comment (and I know YouTube comments are generally pretty low quality) someone says it’s due to the YM2413’s TDM “mixing” and the SMS lacking the correct low pass filter - but I’m not sure how true that is. Yes, I'm beginning to think it might be more common than we may have thought - but now the question is: is this just something that develops over time with all FM Sound on the Mark III/Mk-2000? And if so, will replacing components and/or chips affect it at all? I may just buy a new YM2413 and controller to put into the system and see if anything changes. It really does sound like the sound isn't properly grounded or something of the sort - something that causes a light bit of static. I found an Aleste OST that sounds pretty much identical to my system, but I can't post links yet, as I'm still new. So clearly, this doesn't seem to be an isolated issue. Maybe I can PM the video link to anyone who is interested - it's from a user named karanba72 with the FM Aleste soundtrack. I've recapped the system and even tried taking out a resistor from the circuit i thought was causing it. The quality of the static actually did change slightly, but nothing too notable. I also noticed the solder pads in the Mk-2000 were incredibly fragile and would lift easily. Now I'm wondering if the weakening circuitry has something to do with it. Thanks to all for your continued help! I think we can get this figured out!

sverx Joined: 05 Sep 2013 Posts: 3828 Location: Stockholm, Sweden	Posted: Wed Sep 09, 2020 9:02 am
	Maxim wrote the chip is actually producing sound digitally and it is “mixed” internally, so there’s no logical way to have a single channel go bad yeah that's why I was asking if he could verify it was really a single channel by using ccovell's tool... said that, I have no clue on how to help :\|

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14745 Location: London	Posted: Wed Sep 09, 2020 9:51 am
	It would be good to get someone with electronics knowledge to confirm if the MK-2000 is lacking the output filtering, and if it’s in the FM Unit and the FM mod. That Aleste video: I’m not sure if it’s on real hardware though? Note that “new” YM2413s may be old ones resurfaced, or even fake. I don’t know if real new ones exist.

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Thu Sep 10, 2020 8:36 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	Maxim wrote It would be good to get someone with electronics knowledge to confirm if the MK-2000 is lacking the output filtering, and if it’s in the FM Unit and the FM mod. That Aleste video: I’m not sure if it’s on real hardware though? Note that “new” YM2413s may be old ones resurfaced, or even fake. I don’t know if real new ones exist. Someone like Tim Worthington or db Electronics would probably be helpful, but I can't bring myself to bother them about these issues. That video sounds incredibly similar to my system, so I assume that recording is from a real console? All the emulators/external boards usually have crystal clear FM audio now, even if the sound is not quite right. It seems all the YM2413s on eBay are the same variant. Still wondering if I should try to drop in a new chip or if it'd be pointless, since it seems there could be some other filtering issues at play?

sverx Joined: 05 Sep 2013 Posts: 3828 Location: Stockholm, Sweden	Posted: Thu Sep 10, 2020 8:56 pm
	I seem to remember that where there's a filter there's a capacitor... is that possible that you might try to replace an old capacitor? unfortunately I can't suggest which one :\|

wasup Joined: 05 Nov 2014 Posts: 435 Location: Auckland - NZ	Posted: Fri Sep 11, 2020 12:21 am
	Glimlocker wrote It seems all the YM2413s on eBay are the same variant. Still wondering if I should try to drop in a new chip or if it'd be pointless, since it seems there could be some other filtering issues at play? I would try a different ym2413 and see what happens. Solder a socket onto the board though so that you can easily swap chips without having to do any extra soldering and risk more tracks and or pads lifting off the board. Id gather that any filtering would apply to the whole chip output as all channels are mixed internally, so if the majority of its sound output works fine then its probably the ym2413 itself thats faulty.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14745 Location: London	Posted: Fri Sep 11, 2020 10:48 am
	It’s supposed to be an artefact of the interaction between the channels and the way it’s not really mixed properly; since the noise seems quite wide spectrum, it’s hard to see how low pass filtering would help though.

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Fri Sep 11, 2020 7:50 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	Maxim wrote It’s supposed to be an artefact of the interaction between the channels and the way it’s not really mixed properly; since the noise seems quite wide spectrum, it’s hard to see how low pass filtering would help though. Ok - so is this actually inherent on all FM Sound modules and Mk-2000s on the Master System? If that's true, then I might just hold off on trying to repair/modify it.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14745 Location: London	Posted: Sat Sep 12, 2020 6:54 am
	It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip.

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Sat Jul 29, 2023 7:08 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	Maxim wrote It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip. Came back to update about this issue. After originally posting about this specific Master System, I decided to buy another JP Master System in better condition to see if it's any better. It still has the exact same issue of distortion on the same specific sound channel(s?) - if that makes sense. Essentially the same notes (e.g. the Aleste intro) gives the same effect. I'm beginning to believe that most JP Master Systems may inherently have this bizarre distortion issue. Edit: We also have another report of this distortion on this forum that coincidentally came up when I came to update. So, I'm curious how widespread this is. Just wanted to update everyone, just in case someone out there could take a closer look at the schematics/board and determine what could be the cause.

yogi_om Joined: 05 Apr 2020 Posts: 28 Location: Marseille	Posted: Fri Aug 04, 2023 4:22 pm
	Glimlocker wrote Maxim wrote It may be the case that the MK-2000 has a flawed filter, or that it has suffered from capacitor failure. I really doubt it’s the chip. Came back to update about this issue. After originally posting about this specific Master System, I decided to buy another JP Master System in better condition to see if it's any better. It still has the exact same issue of distortion on the same specific sound channel(s?) - if that makes sense. Essentially the same notes (e.g. the Aleste intro) gives the same effect. I'm beginning to believe that most JP Master Systems may inherently have this bizarre distortion issue. Edit: We also have another report of this distortion on this forum that coincidentally came up when I came to update. So, I'm curious how widespread this is. Just wanted to update everyone, just in case someone out there could take a closer look at the schematics/board and determine what could be the cause. Hi ! Does it happen on Mark III with FM module too ?

ApolloBoy Joined: 30 Jan 2007 Posts: 317 Location: San Jose, CA	Posted: Sun Aug 27, 2023 6:24 am
	From my experience yes, it also happens on the FM Sound Unit.

Glimlocker Joined: 25 Mar 2020 Posts: 19	Posted: Sun Aug 27, 2023 6:54 pm
Glimlocker Joined: 25 Mar 2020 Posts: 19	yogi_om wrote Hi! Does it happen on Mark III with FM module too ? I unfortunately do not have a Mark III with an FM Module to compare it against. The issue seems fairly common place - perhaps universal? - on the JP Master Systems, though.

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