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mreddie
16th December 2008, 07:50 PM
Hi guys,

Was just wondering if anyone is having similar problems to me. Since upgrading to a 60 in 1 board, I've turned the demo music sound to off so that it is quiet unless I envoke a coin or hit the free play button....

But I've noticed whilst in demo mode that I hear some slight buzzing through the speaker that seems to mimic whatever action is happening on the screen during the demo....

It also does a very obvious buzz at startup when the board initialises the 60 games.....

During general play everything is normal and I don't notice the buzz. Is this just a normal thing with these boards? (didn't notice it with the 48 in 1) or could I have something hooked up that I shouldn't?

Turning the sound pot on the board doesn't fix or change the problem?

I can live with it but was just curious if anyone has had a similar experience.....

Thanks

spacies
16th December 2008, 09:03 PM
It probably isn't the game board making the buzz, its more likely your switch mode power supply.
Sounds like you need an EMI filter.

mreddie
16th December 2008, 09:05 PM
Hi Spacies, what exactly is an EMI filter and how does it work?

spacies
16th December 2008, 09:19 PM
Sorry, EMI is Electromagnetic Interference.
It filters out bad 'noises' from your AC line.
Switch mode PSUs are notorious for this. With my new laptop (2.5k) I can't run a cable from the headphone socket to my Hi-Fi with the power supply plugged in because it makes a horrible noise. Just like your machine is doing. You can hear things happening. As soon as I remove the power (a switchmode PSU) it goes away.

You can buy inline filters online. Maybe try Jaycar or DSE.
Some arcade machines already have them but some don't.

mreddie
16th December 2008, 09:34 PM
I'm very much a novice when it comes to arcade wiring, although learning everyday.... are inline filters easy to incorporate into my current wiring setup?

I have something similar to this powering my board.

http://www.highway.net.au/parts/power_supplies_transformers/3126_1.html

I assume a standard power supply.

spacies
16th December 2008, 09:51 PM
No probs.

Yeah that is a switch mode power supply you linked to. They can cause headaches with noise.
A filter will connect to your mains input so you will need to cut and join some wires.

You can get inline ones like this:

http://img.alibaba.com/photo/100786504/0172_Corcom_Emi_Filter_20vk6.jpg

Or an entry model like this:

http://www.lizardlickamusements.com/images/for_sale/electrical/emi_filter.jpg

I use the latter.

Basically your Live and Neutral run through this and it eliminates interference. As soon as power is generated it is full of dirty noise. The power lines it runs through act like giant aerials which pick up more noise and by the time it hits sensitive electronic equipment it is crap. Most electronics have EMI/RFI filtes installed at the power entry point.

mreddie
16th December 2008, 10:16 PM
Hey thanks for the pics.....very helpful, will try Jaycar for one.

mreddie
17th December 2008, 09:30 AM
And because I have no experience with power wiring whatsoever, what do I remove from my current power supply to plug into the later device you've described.... sorry but my experience in this stuff is limited and I get very worried touching anything power related.

spacies
17th December 2008, 09:37 AM
:D

Cut your power cord off about a foot before it enters you cab. Strip back that cable and get some wire crimps and connect them to the end of each wire. Live, Neutral and Earth.

On the back of the EMI filter it has an L (for Live) N (for Neutral) and Earth. Connect the power cord wires to the appropriate pins. Then use a PC cord as the new power cable that plugs into the cab.

mreddie
17th December 2008, 09:46 AM
Would something like this just work over the power cord?

http://www.dse.com.au/cgi-bin/dse.storefront/49482ef5055d3436273fc0a87e010623/Product/View/R5124

spacies
17th December 2008, 09:51 AM
Wouldn't hurt to try one of those if you dont want to cut anything :)

mreddie
17th December 2008, 09:52 AM
Hey Gotcha Spacies, thanks so much....

spacies
17th December 2008, 09:55 AM
You are welcome

mreddie
17th December 2008, 09:58 AM
My wires out of my cord are green, light blue and brown.

spacies
17th December 2008, 10:07 AM
Green = Earth
Light Blue = Neutral
Brown = Live/phase

mreddie
17th December 2008, 10:19 AM
Cool, will leave you alone now..... :-)

mxd
17th December 2008, 10:29 AM
just remember disconnect lead from wall plug before you cut it :)

Or if your as bad/careless/stupid as I am make sure you put a earth leakage (not really a earth leakage but that's what they are more commonly know as) safety switch on you switch board.

I was using the electric hedge trimmer last weekend and chopped straight through my extension lead. The safety switch clicked off and I didn't feel a thing, the wife was rather upset/shaken when I showed her, I was just unsure whether it was because what I did was stupid or the fact the safety switch worked :unsure :lol

mreddie
17th December 2008, 11:43 AM
OK so I've purchased one of those EMI devices this morning, hooked it up (yes I did it correct HOORAY) and the noise through the speaker still keeps buzzing away as before. So I went and plugged some headphones into the socket on the board itself and can hear the buzzing in the headphones too..... which says to me the board is at fault........ should have checked the headphone socket first... Is there anything else I should try before hassling the guy I bought it on Ebay for a replacement????

spacies
17th December 2008, 11:47 AM
You bought an entry EMI or one of those clip on things?

mreddie
17th December 2008, 11:50 AM
EMI entry

spacies
17th December 2008, 11:55 AM
Thats odd.
Do you have another PSU you can try.
I doubt it will be the PCB.

**edit: maybe try a PC power supply**

David_AVD
17th December 2008, 11:57 AM
...But I've noticed whilst in demo mode that I hear some slight buzzing through the speaker that seems to mimic whatever action is happening on the screen during the demo....

Does the speaker hook directly to the game board? If so, it's possibly just a crap design. Some laptops have the same problem - move the mouse and you hear noises in the headphone output. If so, nothing you can really do.

mreddie
17th December 2008, 12:01 PM
The speaker currently is hooked up via the Jamma cabling.... but it also has a headphone outlet attached directly to the board.... the buzzing comes out of both the JAMMA speaker and the headphones when plugged in to the board..... surely that says the board is at fault???

David_AVD
17th December 2008, 12:49 PM
I'd say poor board design or bad capacitors on the board. The only other thing may be your PSU is putting out a lot of ripple on the DC side but you'd need to substitute a known good PSU to find out.

Brad
17th December 2008, 01:14 PM
Sorry to butt in on this thread but if I buy one of those things pictured second. I can run power directly to it from my wall socket and have it power up a powerboard?

I want to neaten my jukebox. Currently run and extension lead to a powerboard inside the cab. I want to wire the powerboard up to this device pictured above and have the exterior of that socket on the outside only. Would this work okay?

also how would I go about enclosing the wiring internally. Is there something else I should use?

Cheers,
Brad

David_AVD
17th December 2008, 01:20 PM
I'm going to do the same to some of my machines. An IEC inlet is so much neater than the cable hanging out the back. Better for transport too, especially if you can recess it using a metal plate.

As for inside, some of those inlets have a matching plastic boot available.
edit: see post 29

spacies
17th December 2008, 01:54 PM
Yes you can buy them without the EMI filter, just a straight power entry or power entry with a switch.

Brad
17th December 2008, 02:05 PM
Oooh nice. I want to do this to all my cabs and the juke. Powerboards hidden way and one nice shiny neat socket on the outside. Do DSE or Tandy stock these or I'd probably need to go to an electrical trade store or something?

Cheers,
Brad

David_AVD
17th December 2008, 02:11 PM
Brad, just added the inlet (http://www.audiovisualdevices.com.au/viewprod.php?productid=P8324) and boot (http://www.audiovisualdevices.com.au/viewprod.php?productid=IEC20) to the arcade page.

Brad
17th December 2008, 02:13 PM
YAY! I'm going shopping and I'll need 3 of each ;)

Cheers,
Brad

spacies
17th December 2008, 02:14 PM
These are the ones I used before the EMI:

http://pic4.picturetrail.com/VOL757/2715941/16178946/241715005.jpg

mreddie
17th December 2008, 10:13 PM
Sorry to harp on about this but it's really annoying me this problem, particularly as it wasn't there before. One thing that I have changed is I took and old arcade monitor out and replaced it with a new LCD which is self powered (not via the JAMMA). Could it be that the PCB is receiving too many volts now that the power supply doesn't support the old arcade monitor anymore? If so can I turn the voltage down on my supply ? I only ask this as I saw a post in another thread about the 60 in 1's from GameDude that read "...5.2volts is a little high for this PCB and faults are know to occur that high, lower to 5.05volts max (measure on the PCB side of the connector and NOT the connector itself)". I have a switching power supply.

David_AVD
17th December 2008, 10:29 PM
Ah, I didn't see the bit about it being a new symptom. Possibly due to incorrect earthing with the new monitor. Very hard to trouble shoot that sort of thing without being there. Sorry.

mreddie
17th December 2008, 10:33 PM
The new monitor isn't earthed, it just has the VGA cable connected to it and then the other end of the VGA plugs directly into the board.... at the moment it has no relationship to the JAMMA or power supply.....should it have? The LCD runs on it's own power.....

David_AVD
17th December 2008, 11:17 PM
OK, simple test. Does the buzz disappear when you turn the LCD monitor off?

mreddie
17th December 2008, 11:36 PM
No....

Bally
18th December 2008, 12:50 AM
When you disconnect and remove the LCD those the noise go way ?

mreddie
18th December 2008, 07:10 AM
The LCD for mine has nothing to do with the problem. The buzzing occurs with or without it. But does no one think it could be a power problem from the power supply, with the PCB getting too many volts???

spacies
18th December 2008, 07:21 AM
Have you tested the voltages?

I would have assumed that would be something that you had already done.