Speaker hummm

[Chris]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Is speaker hum normal from an upright whenever it is on? The speaker is
earth ground.
I now wonder if this is a function of a filter board? I'm not using one
between the Galaga PCB and switchable power supply...
What do you think about that? Thanks for any advice!....Chris

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

i dont know if it is normal or not but mine does it also. the speaker
is grounded. the board is freshly repaired by greg at gls1.

let me know if you find the cause.

phil

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Hi All,

Some hum is normal. Not only do you need to make sure the
speaker is grounded but also check the following. Hum is uasully
induced into the wires that lead from the board to the speaker by a
neighboring wire in the bundle.

You can check the following.

1: Center pin on your AC power cable is not broken off.

2: All of the metal in your cabinet is grounded together. Take off the
old grounds clean them up and retighten them. I add a starr washer.

3: Seperate your wires that go to the speaker from the rest of the
bundle as much as possible. Try and not tie them up with the AC to the
Flourescent light fixture. ( Make sure it is grounded also). As much as
we all like nice clean and neat nicely tied up cable runs this is were
most of the hum problems I encounter end up coming from. Leaving the
wires loose is not a bad thing.


4: Check your DC power supply for AC ripple.

5: Clean the edge connector on your board. Check all ofthe connections
on your power supply. Make sure one of the grounds go to Earth ground.

Take a Look At therealbobroberts.com
He has a really good article on grounding.

Sometimes we do over ground and you end up with a hum.


You can also use a ohm meter with the power cord unpluged. With a clip
lead on earthground. Go around to your different points of metal.
Coindoor,control panel,flourescent light fixture,on/off sw,coin
box,board,power supply and depending on the monitor chasie. You should
read less than 2 ohms difference between parts.

Good Luck

J & R

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Which greg fixes boards????????

On 12 Apr 2005 13:01:32 -0700, "Zimmer" <phil@zimmerland.com> wrote:

>i dont know if it is normal or not but mine does it also. the speaker
>is grounded. the board is freshly repaired by greg at gls1.
>
>let me know if you find the cause.
>
>phil

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

On 2005-04-12 15:17:35 -0400, "Chris" <gotstik@gmail.com> said:

> Is speaker hum normal from an upright whenever it is on? The speaker is
> earth ground.
> I now wonder if this is a function of a filter board? I'm not using one
> between the Galaga PCB and switchable power supply...
> What do you think about that? Thanks for any advice!....Chris

You'll never get all the hum out. It's just part of the overall package.

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Bryan Los wrote:
> On 2005-04-12 15:17:35 -0400, "Chris" <gotstik@gmail.com> said:
>
> > Is speaker hum normal from an upright whenever it is on? The
speaker is
> > earth ground.
> > I now wonder if this is a function of a filter board? I'm not using
one
> > between the Galaga PCB and switchable power supply...
> > What do you think about that? Thanks for any advice!....Chris
>
> You'll never get all the hum out. It's just part of the overall
package.

On my Phoenix, I get a cool "hum" sound when there's a level change
(warp), thought it was actually a sound effect, but it doesn't do it
when the monitor is unplugged. Not sure if it's by design, or if it's
just a cool side effect of bad grounding

 

[Scott]

Archived from groups: rec.games.video.arcade.collecting (More info?)

I've battled speaker hum in a lot of games and it seems to be caused by
so many things....

Sometimes it's a grounding issue....sometimes it's bad caps in the
power supply and/or game PCB....etc etc.

Some games always had that "hum" but you didn't notice it in an arcade
full of games... but you sure do at home.

 

[Chris]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Thanks for the tips, I had tied the marquee light and speaker wires, undoing
them helped some.

Thanks again...Chris

"J & R" <arcadeadventures@aol.com> wrote in message
news:1113344684.661003.17430@z14g2000cwz.googlegroups.com...
> Hi All,
>
> Some hum is normal. Not only do you need to make sure the
> speaker is grounded but also check the following. Hum is uasully
> induced into the wires that lead from the board to the speaker by a
> neighboring wire in the bundle.
>
> You can check the following.
>
> 1: Center pin on your AC power cable is not broken off.
>
> 2: All of the metal in your cabinet is grounded together. Take off the
> old grounds clean them up and retighten them. I add a starr washer.
>
> 3: Seperate your wires that go to the speaker from the rest of the
> bundle as much as possible. Try and not tie them up with the AC to the
> Flourescent light fixture. ( Make sure it is grounded also). As much as
> we all like nice clean and neat nicely tied up cable runs this is were
> most of the hum problems I encounter end up coming from. Leaving the
> wires loose is not a bad thing.
>
>
> 4: Check your DC power supply for AC ripple.
>
> 5: Clean the edge connector on your board. Check all ofthe connections
> on your power supply. Make sure one of the grounds go to Earth ground.
>
> Take a Look At therealbobroberts.com
> He has a really good article on grounding.
>
> Sometimes we do over ground and you end up with a hum.
>
>
> You can also use a ohm meter with the power cord unpluged. With a clip
> lead on earthground. Go around to your different points of metal.
> Coindoor,control panel,flourescent light fixture,on/off sw,coin
> box,board,power supply and depending on the monitor chasie. You should
> read less than 2 ohms difference between parts.
>
> Good Luck
>
> J & R
>

 

[Chris]

Archived from groups: rec.games.video.arcade.collecting (More info?)

I had an interesting experience when I earth ground the monitor chassis..
The game went into service mode... What is with that.. I immediately undid
it.. I guess the monitor doesn't get grounded?


"RedWolfJC" <redwolfjc@excite.com> wrote in message
news:1113411605.169241.255810@o13g2000cwo.googlegroups.com...
>
> Bryan Los wrote:
>> On 2005-04-12 15:17:35 -0400, "Chris" <gotstik@gmail.com> said:
>>
>> > Is speaker hum normal from an upright whenever it is on? The
> speaker is
>> > earth ground.
>> > I now wonder if this is a function of a filter board? I'm not using
> one
>> > between the Galaga PCB and switchable power supply...
>> > What do you think about that? Thanks for any advice!....Chris
>>
>> You'll never get all the hum out. It's just part of the overall
> package.
>
> On my Phoenix, I get a cool "hum" sound when there's a level change
> (warp), thought it was actually a sound effect, but it doesn't do it
> when the monitor is unplugged. Not sure if it's by design, or if it's
> just a cool side effect of bad grounding
>