Black Hole sound hum - sound hum, speech clean

[Guest]

Archived from groups: rec.games.pinball (More info?)

I've been looking through old posts and it seems like a lot of BHs have
similar problems.

I have a loud hum, normal volume speech, and barely audible sounds.

Hum varies with the main sound pot behind the coin door. I've adjusted
the sound and speech pots on the sound board (R15 & R16) to balance
them out, but turning up the sound pot (and ONLY the sound pot) causes
more or less hum.

Now, I know by earlier posts and google searches that there are several
things to check. In general - proper grounding, board connections, the
big caps in the cab, speaker connection, the speaker itself.

Something I did not find in past posts was what does it mean when it's
the SOUND side only where most of the hum is being introduced? Speech
by itself (like in attract mode) is pretty clear of hum.

Looking at the schematics I see several capacitors in the audio
circuits, particularly C31 on the sound line and C32 on the speech
line. If I understand the schematic properly, these are the only two
caps which are line specific. Knowing that a bad filtering cap is one
cause of hum, that the hum is very evident in sounds but not in speech,
I'm thinking replacing C31 should be the first thing to try, since
everything else that can cause hum would cause it equally to both sound
and speech.

Is my thinking way off base? Thanks, Q

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

Have you tried adjusting the "amplitude adjust", R13 pot?

df

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

My issue was actually the coin door pot itself.

Put a 15w volume control instead and now I can adjust the R15 & R16
properly and take out the hum.

Man that thing can be loud and annoying eh ?!

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

You're on the right track. My BH had the oppisite problem - ok sounds but
weird crackly voice. I dont have the schematic in front of me, but there
were 2 disk caps - I beleive they were the ones you listed. I will check for
you!
-Jeff


"qfrost" <qfrost@yahoo.com> wrote in message
news:1124931137.762318.317160@z14g2000cwz.googlegroups.com...
> I've been looking through old posts and it seems like a lot of BHs have
> similar problems.
>
> I have a loud hum, normal volume speech, and barely audible sounds.
>
> Hum varies with the main sound pot behind the coin door. I've adjusted
> the sound and speech pots on the sound board (R15 & R16) to balance
> them out, but turning up the sound pot (and ONLY the sound pot) causes
> more or less hum.
>
> Now, I know by earlier posts and google searches that there are several
> things to check. In general - proper grounding, board connections, the
> big caps in the cab, speaker connection, the speaker itself.
>
> Something I did not find in past posts was what does it mean when it's
> the SOUND side only where most of the hum is being introduced? Speech
> by itself (like in attract mode) is pretty clear of hum.
>
> Looking at the schematics I see several capacitors in the audio
> circuits, particularly C31 on the sound line and C32 on the speech
> line. If I understand the schematic properly, these are the only two
> caps which are line specific. Knowing that a bad filtering cap is one
> cause of hum, that the hum is very evident in sounds but not in speech,
> I'm thinking replacing C31 should be the first thing to try, since
> everything else that can cause hum would cause it equally to both sound
> and speech.
>
> Is my thinking way off base? Thanks, Q
>

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

So much so I can barely hear the sounds. I can hear the speech fine,
the that hum just overpowers the effects.

Great game though. So different from Williams and Bally - Q

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

It is a really challenging game to play. I installed a 50,000uF capacitor
bank across the solenoid rectifier and the game plays extremely fast. The
ball shoots up too quick from the bottom playfield sometimes.

All the best,

Tom Kennedy
Australia


"qfrost" <qfrost@yahoo.com> wrote in message
news:1124931137.762318.317160@z14g2000cwz.googlegroups.com...
> I've been looking through old posts and it seems like a lot of BHs have
> similar problems.
>
> I have a loud hum, normal volume speech, and barely audible sounds.
>
> Hum varies with the main sound pot behind the coin door. I've adjusted
> the sound and speech pots on the sound board (R15 & R16) to balance
> them out, but turning up the sound pot (and ONLY the sound pot) causes
> more or less hum.
>
> Now, I know by earlier posts and google searches that there are several
> things to check. In general - proper grounding, board connections, the
> big caps in the cab, speaker connection, the speaker itself.
>
> Something I did not find in past posts was what does it mean when it's
> the SOUND side only where most of the hum is being introduced? Speech
> by itself (like in attract mode) is pretty clear of hum.
>
> Looking at the schematics I see several capacitors in the audio
> circuits, particularly C31 on the sound line and C32 on the speech
> line. If I understand the schematic properly, these are the only two
> caps which are line specific. Knowing that a bad filtering cap is one
> cause of hum, that the hum is very evident in sounds but not in speech,
> I'm thinking replacing C31 should be the first thing to try, since
> everything else that can cause hum would cause it equally to both sound
> and speech.
>
> Is my thinking way off base? Thanks, Q
>