DrewKrewUK

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
OR...
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!!!

Regards,
DK.

Old topic, i know, but i thought i'd conclude it for the sake of maintaining a knowledge base.
Here is Barcrest: Royal Exchange Club MPU5 settings
(many struggle with Barcrest clubbers)
 SketchGuru_20160313230728.jpg   571.41KB   2 downloads

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.
Coincidence?
Hmmm...
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.

DREW.

Hmmm... tempting, that lower monopoly glass is the same as my lower coronation street monopoly club machine glass... win line has worn off on one reel on mine and stuck itself in fragments all over the reel window!

How much would postage be on two please?