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Barcrest Genesis Speaker Buzzing Question

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#1 markjbevan



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Posted 05 April 2007 - 06:05 PM

Evening All,
Apologies for two questions in one day, but I know a lot of you guys really know what you're talking about ;O)

This week, Ive taken delivery of another machine for the games room - Barcrest Hyper Viper (one of my faves!).

Ive noticed the noise other posters have previously mentioned - there is a "electrical interference" type of high pitch buzzing, which changes as the lights change. For example, when in refil mode (and the lightsa re mostly off) the noise stops. When in attract mode or when playing the noise is present.

I understand from Bazpeebs post on this subject that the noise is normal with Barcrest machines in the Genesis cabinet, so Im not too worried.

However, my question is has anyone done anything to reduce the noise? I was thinking of removing the speaker and maybe putting some material in front of the cone and replacing it - I thought this would muffle the noise, and I could turn up the game volume to compensate. The noise stays the same level whether the volume is high or low.

Has anyone tried this or anything else, or should I just learn to live with it? Ive got other machines with similar noises, but this is probably the worst.

Many thanks,
Mark :o)

#2 cyberface


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Posted 05 April 2007 - 07:57 PM

had this problem on a few cabinets, im sure its a problem with the psu not earthing properly, my spiker 's psu broke, so i replaced it with one from another genisis, but its crackles, so i just unplugged the speaker!

#3 impact


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Posted 05 April 2007 - 08:24 PM

barcrest added mains filter box on machines around about the time of yours 2004/5 and now to date a small emi filter which clips on the barbus line 1.5" by 1" this was use to quieten the noise from which was on the barbus line the main question is your mains feed in the house any good

this are the only machines that i could think of that barcrest used the mains filter box type unit on

super star
(bottlebank vivid)
high flyer
all fired up
vamp it up
hot stuff

other machines used the barbus line filter
.._-=It`s not a problem only a challenge =-_..

#4 skabaz


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Posted 05 April 2007 - 08:32 PM

i have stuffed the speaker with tissue and this sometimes muffles the noise slightly.


#5 impact


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Posted 05 April 2007 - 08:38 PM

hello baz

lol :D
.._-=It`s not a problem only a challenge =-_..

#6 markjbevan



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Posted 07 April 2007 - 08:11 AM

Hi Guys,

Thanks for that - I dont really want to unplug the speaker, as the sound isnt THAT bad and I dont want to lose the coll sounds and music!

I think I'll go with Baz's idea and experiment with muffling the sound. I was thinking of removing the speaker, putting some cloth in front of the speaker gtill (from the inside) and reattaching it. Hopefully this will reduice the buzz, but not affect the sound too much.

Hopefully I'll have a chance to do this over the weekend, so I'll let you guys know how I get on.

Thanks again,

Mark :o)

#7 markjbevan



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Posted 09 April 2007 - 04:30 PM

Afternoon All!

Just to let you know I fixed this problem today!

I cut two squares of a Vileda cloth (the thin, but dense one), remove the speaker, then screwed the speaker back with the close sandwiched between the inside of the grill and the speaker.

Although there is still a veryu feint buzz, it is much much better than the high pitch buzz I had previously. Also, I think the sound is slightly better as the top frequencies are slightly cut so the sound is slightly more solid and bassy.

I know it is a fairly crude solution to the problem, but it was simple (less than 5 minutes to do) and now you can hardly hear any buzz at all.

Thanks again for the advice.

Best regards,

Mark :o)

#8 DrewKrewUK



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Posted 23 February 2016 - 12:59 AM

I'm going to resurrect this old thread, being a Barcrest mpu5 genesis cab collector and see if some light can be shed on this issue a little more.
Out of 12 mpu5 genesis cabs i currently own i do have to say 10 are perfectly silent. Not even a trace of background noise or interferance from the speaker, so i don't class this as an issue across the lot.
However two i own do generate a darn annoying noise in time with the light patterns. The more lights illuminated the louder the noise.
Coincidently, both these machines sound a little more "tinny" with the treble but the speakers are fine and they still have a good bass to them so i'm not going to put it down to iffy speakers just yet.
First thing i tried was naturally exchanging psu's for ones out of known silent machines free of hum interferance issues.
No change, so that eliminated any concerns that the power supply was the cause.
Next i pulled out the mpu5's and replaced the two electrolytic caps on the audio circuit.
Again, no change.
Next i tried swapping out the mpu5's.
Guess what, still no change.
So where is the source of the hum?
I looked to the lamp boards.
On all my "silent" genesis cabs i notice they are using two seperate MUX5 boards dated 1996 issue 1.
On the two noisy genesis cabs they use a single larger MUX5E board dated 2001 issue 4.
I've yet to go any further than this but i would like to finally put a nail in the coffin regarding Barcrest/Red Gaming speaker interferance and i think it's a reasonably achievable task.
I'll use this post as a log on my progress that way it keeps things on the subject all in one place and anyone else seeking resolve might then benefit.
Might, i say lol.


#9 chasnbons


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Posted 23 February 2016 - 08:22 AM

I shall watch this with great interest.


I've had a similar problem ever since the MPU5 battery died in my Enhanced Rio cab and I changed the board.


Have 2 spares and tried them both and ended up with the same problem on both to different degrees. (One being louder than the other)


The noise is only there when machine has doors closed and fully booted, and is either in time with the attract lights or nearly constant when being played.  It isn't THAT loud, just a bit annoying, and I suppose if it was in an arcade you'd not hear it with all the background noise etc.  But being in the much quieter home environment, it's much more noticeable.


The PSU also makes a louder buzzing at the same time.


Before the MPU was changed everything was silent, no buzzing at all.  Nothing else has been touched.


It has a 1996 MUX5 Iss1 board.


I'd sort of got used to it till I read this, but now you've highlighted it I look forward to the outcome.

#10 DrewKrewUK



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Posted 16 October 2018 - 12:51 AM

Again, i kniw this is an old post BUT...
I have solved the great mystery of MPU5 genesis speaker buzz/humm.
Everyone has given in to saying "they all do it"
No. No they don't.
The succeptible ones are ones with a single MUX5E board (the larger lamp board) to run all the lamps.
Machines with 2x smaller MUX5 boards don't suffer with this.
So down to solutions!
Well, you can solve this properly by replacing the one MUX5E board for two MUX5's, mounting them, and re-route the lamp connectors to them to share the load across them both although you will need to gut the old barbus red loom to the power supply and replace it with the one that has two lamp board connectors
Lets revisit the MPU5 mainboard itself.
Now looky here! it has an inbuilt lamp controller! Ah-ha!
It's not really "oomphy" enough and accomodating to take the entire lamp load but it can handle two banks of lamps plus any led panels.
So now there's opportunity to reduce the lamp load of the straining MUX5E and connect direct to the MPU5.
Now whilst this seems a very easy and convenient trick it also poses a few issues.
1) Even after unclipping the lamp looms from the main harness run, you'll probably have to relocate the main mpu5 board closer. Luckily they unclip out of the mounting back plate and can be refitted more up and left of the backboard without being short on cable lengths.
2) The main reason barcrest began using twin mux5's or mux5e's: running too many lamps direct off of the main mpu5 board (eg: spiker the biker) for long durations such as they woukd on site causes fuses to heat up and prematurely pop.
So only utilise one of the two mpu5 lamp sockets!

By simply sharing the combined lamp load across 2x MUX5'S or an MUX5E and the MPU5 itself you will elliminate the horrible throbbing electrical humm noise from the speaker.

It's well worth doing!!!


#11 Mavroz


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Posted 16 October 2018 - 07:32 AM

Bit of music always worked for me.... 👍

#12 richy1976


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Posted 16 October 2018 - 10:36 AM

I was thinking a sheilded power lead might do the trick as used on high end hifi.

#13 Mavroz


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Posted 16 October 2018 - 12:24 PM

Sit in a room with several Project and Maygay Epoch machines (with a mk1 psu) and you will know about humming...

Mpu5 is a very minor hum if any at all.

#14 I have finished

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Posted 16 October 2018 - 01:07 PM

Shouldn't really be putting this in here, I really think for authenticity, Wizard should add a buzzing speaker effect in the latest MFME release in the Genesis folder. I think all machines of some kind, whether Barcrest or not, kind of have a buzz. Our local's magic 10 has a buzz, as well as Oxo, and I think party time does too.

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