New 16 MHz Double Diamond Owner help with the BUZZ!

[Olds442]

Hi All,

I'm the new owner of a late S+ machine with the 16 Mhz MPU.  Machine functions very well and for a game that is almost 24 years old it is very good condition.

I have been reading that these machines tend to have a buzz/humm/static from their speaker while idle and mine is like the others.
I have also been reading that you need to "put something in line with the speaker" to reduce it/make it go away.

I know on the S2000 games the recommendation is a 47K ohm 1/2 watt resister on the ground wire (white) for each non-amplified speaker.

Is this the same fix for the S+ games with the 16 MHz main board?

Any recommendations out there?

Thanks

[Stayouttadabunker]

An S+ speaker configuration just isn't in any way similar to an S2000 sound setup.

There's only one single speaker down below on the bottom of the door panel near the door hinges that only uses two wires....nothing more.

It's a rather simple setup that does not utilize a sound amplifier like the way an S2000 uses.

[Olds442]

Thanks,

Yes I understand that my S+ machine has just one speaker on the door, behind the front flip down panel. 

Is there anyway to reduce the static noise that the 16 Mhz board make while the machine is turned on?

[Stayouttadabunker]

I don't know....I've never once ever messed with the sound on an S+.
I've never had any static noise.
Can you make a video of it making the static noise and post it up for us to hear?

[Olds442]

Thanks so much for your help and fast replies.

https://drive.google.com/file/d/1q-YirhYmubnY2OoOfRzDeyIdwlOMJQUr/view?usp=sharing

I have attached a sound recording of the machine from power on to ready for play.  I have also narrated the high pitched buzz, humm static, that you can hear.   You will hear near the end of the recording for a split second at the end of the boot/self test it cuts out.. but then for regular play it comes back.

I have unplugged the speaker during play and it is definitely the source of the noise.  Is this the noise that 16 MHz board make?

Machine plays fine and works perfectly otherwise.  If it helps it is a 1998 $1 Machine set up for large coin tokens.

Would you like a longer recording with coins going in?

Thanks again.

[Stayouttadabunker]

Very good audio recording.
I'm hoping someone else hears this because my hearing isn't too good I'm afraid.
Also, I cannot quite make out what you said at 18 seconds. 
I'm sure another member with better hearing will chime in and help you out!

[Olds442]

On the recording at ~18 seconds I say "It is doing its test" and you can hear the reels "whrrr" and the bill validator do a self test "squeak squeak... squeak squeak"

After a little more work on this I can confirm that the annoying noise is exactly 3300 Hz so it is about the third highest note a piano can make and it should be easy to build a low pass frequency filter to  filter it out.

Has anyone else tried to add a low pass filter to the speaker on the 16 Mhz board?   Any risk with this?

In theory, if I use a 30K resistor and a 3.3uF capacitor the filter will start to kill any noise above ~2000 Hz

Can anyone confirm that the green speaker wire is positive and the white one is negative/ground?

Thanks again

[jay]

The buzz with the 16mhz boards is a well known issue.
A filter as you have described should remove it.

Most here have found it simpler to go with the 10mhz boards, due to a wider number of game chips available, and availability of parts.

[Olds442]

Thanks

Yes, I read lots about the 10 vs 16 boards... and since the 16 board is working fine... I might just go with it until it dies and then look for a 10 board with a Double Diamond Game chip.

If My filter works and I don't fry something I will post the results. 

Just to confirm... The green and white wires to the speaker are green = positive and white = ground?

[jay]

That board will never die..... the S+'s are rock solid.
The only way they got those out of circulation was to deprecate the bill validator so it couldn't take new money.

They didn't once sell a S2000 overseas as they were buying up all the used S+'s until they couldn't take cash.
Some Caribbean casinos still have them....

The reel chip - the one that controls the double diamond theme can be moved from the 16mhz board to the 10mhz board.
The game chip is not compatible but the very common 731 or 1271 will work just fine with the reel chip as a combo.

The major difference with the 16mhz as far as the game chip goes is that the volume is controlled through a software setting where as the 10mhz board has a manual dial (rheostat) that extends through the edge of the game tray to control the volume.

Sorry I can't help you with the wiring but the schematic is in the S+ electronics manual - and the manual can be found in our downloads section.
If you look at the speaker itself it might have the +/- etched on the wiring tabs as well.

[bunsen]

mine makes the same annoying noise, at first i thought it was a loud fan but realized the machine doesnt have one.  I have since unplugged the speaker like you did.  if you do find a solution id like to hear about it.

[Olds442]

My background is 30+ years working in IT with a degree in Computer Science from the 80's so I know how to work with computer circuits but not how to build them.

As a first attempt I built a high impedance "RC" (Resistor Capacitor) low pass filter because it was cheap (<$2), I had some of that parts on hand, and has the least chance of damaging anything "up steam" of the filter.

It didn't work. (It filtered out all sound)

An Electrical Engineer buddy of mine suggested a low impedance "LC"  (Loop/Inductor  Capacitor) low pass filter.  It will cost a little more (~$5) to build.  I will try that on Monday.

If I get some thing that works I will definitely share.

[Olds442]

I'm back from vacation now and the LC (loop/ capacitor) low pass filter shows some promise. Once I get it right I will post a schematic, parts list and picture. 

So far I have a  470uH 3A  Inductor loop working with a 35V 12.5uF Capacitor (about $6 worth of parts) and the buzz is half gone and all of the other noise events are all there and I can't hear any loss of crispness of those pings, bongs and  the reel spin tune.   

I'm going to try with a 22uF Capacitor and see if that is better. 

This will be a balance of filtering out the 3100Hz noise and making the sounds that we want to keep "muddy"

[Olds442]

I'll leave it up to the mods if they want a separate post on the solution, but on my machine at least I have eliminated almost all of the buzz

You need to build one of these:


That is the schematic for a passive low pass Loop Capacitor (LC) circuit.

You will need a 470uH Inductor (pick one with the lowest resistance you can find)
https://www.ebay.com/itm/153400933275?hash=item23b7687b9b:g:bqoAAOSwESdce~OY
That has about 1 Ohm of resistance.


It took me some playing around but I found that a 35V 100uF Capacitor almost completely killed the buzz and only impacted the tone and volume slightly.

https://www.ebay.com/itm/391434346018?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D240680%26meid%3Dfa79ce89d1b1437686e8c4ecaeddb476%26pid%3D101195%26rk%3D3%26rkt%3D12%26sd%3D362447702224%26itm%3D391434346018%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseWebMskuAspectsV202110NoVariantSeedKnnRecallV1&_trksid=p2047675.c101195.m1851&amdata=cksum%3A391434346018fa79ce89d1b1437686e8c4ecaeddb476%7Cenc%3AAQAHAAABMK6kjqEQMYM5Aq%252BOhcaIlwco9wYktoCXAP3D6Fo7POUdlJK1eqFqv5Y7huO6nLq7hjqYjs5sEMudJpf20WlRkR7Mqq2vj9ewhyxtXrUo7ivn4PcZbuW%252B8OTA7vUEcU1b68EneyT%252Bz5eRek1iCNwF06sVCy12tM%252FVROEqsGuBZ7R0oySECqb%252Fjd8BjAHKR4KY%252FqkyBkvhUAMI6cmnuDF3R2d0AYbqW4R9eHgjaufRcbBOrrozVrPD5qBGXKo9TAyNKRiTb4kUmfHEa%252FYbOl2mTqJh0Iu6Si6DbBYOjkOZRKDICIuvkyt0z7K%252BFwv42xALknASkUPDhVzijmW10Dji5wXuTM9qqrruQ1LU%252FJH6arkK8bYKklWO8Ir%252Fj8hB5WiFcV1M9gp97inAS7u7leitG4s%253D%7Campid%3APL_CLK%7Cclp%3A2047675

male and female connectors

female
https://www.ebay.com/itm/353033419166
male
https://www.ebay.com/itm/143548055974

The connectors are nice since you can just plug the filter in and not have to cut any wires in the slot machine so this is easily reversible. 

The ebay links are only examples,  I bought all of the bits at my local electronics house for < $6

On my machine White was + and Green was  -

So solder it together like this...



And plug it in



As a final step I will build a small plastic box on my 3D printer, or you could protect it with electrical tape or what have you.

This will decrease the volume of the machine by about 10% but the buzz is almost completely gone!

Do this at your own risk. I am not an electrical engineer, but I do play one on TV from time to time.

[Stayouttadabunker]

Normally of course, these machines were operating IN an extremely noisy environment.... so some speaker buzz just wasn't a factor.
Running these machines in the quietness of your home is a different story....haha

Personally, I think your solution is awessome!! 

I would of liked to HEAR the difference with the mod in an "after"sound bite.
Maybe I'll make one to find out for myself.   

[gameking6]

Normally of course, these machines were operating IN an extremely noisy environment.... so some speaker buzz just wasn't a factor.
Running these machines in the quietness of your home is a different story....haha

Personally, I think your solution is awessome!! 

Another reason a 10% reduction in sound may even be welcomed😀