V20/20 NO Sound

[stormrider]

Working with my first V20/20 i-reel transparent sky spirits
game is up and running but has no sound.

Some things ruled out
sound card tested good in another alpha
speakers also test good.

Gray cable going into mpu line out wires all intact

Normally on these gray cables it splits off and connects
to the upper board marked audio in and speaker out
but my upper board is different audio power lower right in picture which is PCA209450
The molex size is different so I'm wondering if there
is some kind of pigtail harness I'm missing to supply power.

Also if I go into sound setup I can move the volume up and down
I can also select mixer but game volume is stuck on 10 and wont move
external volume does move but none of the above do anything

I get nothing no buzz,hiss,pop,nada

Any help or pictures of what I might be missing would be great.
Thanks.Tim

[777sizzler]

Seen this on some that had player tracking removed.  The tracking sys is tied into the sound.  Also To check the audio out (green jack) on mpu plug in some powered computer speakers or similar to see if audio is present to rule out mpu. 

[stormrider]

Hey Barry,

Yes mpu line out (green) with external speakers
I do get game sounds so I can rule out the mpu.

When I follow the harness from behind (sound card)
to top and bottom speakers I find no other source of
power other than a 2 pin molex at the bottom of the cabinet
shown in the picture,those wires show a tag of 24v very thin
wire I might add,
also tried to read voltage on those wires and it showed nothing.

I don't see where this sound card is getting any power source from.

Just to add I also swapped both supplies
seen wacky things happen with those before.

Maybe somebody with a I-reel can confirm if
the audio power 4 pin molex has anything plugged
into it on lower right PCA209450
That's the only spot I see where it could get power.

[777sizzler]

Where is your amp board?.  The 2nd pic you posted in thread one has my interest.  I sold my last transmissive left here a while back so nothing to compare to.  It does look like a simple fix but-Don't fry anything until you know what's what. It is just not getting power/amplified, etc. (the output signal).

[rickhunter]

The amp circuit is on a tray top right of the main section (to the right of the reel controller board).  The amp may be bad.  Also pull out the amp and look for burned traces behind it on the backplane, that has also happened to me.

[stormrider]

The amp board has been tested in another machine
there is no board behind it to look for any burn marks
this is a different back board used for transparent set up
but uses short amp board.

The second picture you refer to is the 2 molex connections
coming off the gray cable which I see nowhere to connect to.
That's why I ask maybe I missing a board or some pigtail
harness to connect to the audio in which is 4 holes.

I don't have another transparent machine to compare with
 

[cartman765]

Hi, I pulled my machine apart and traced the harness down to the back plane and the power to the amp comes from connector P8 and comes out to a 2 pin connector with a gray/yellow and yellow/blue wires hope this helps.

Dale

[stormrider]

Hi Dale,


Thanks for taking the time to look.
I posted a picture of that connection
also checked it for 24v and showed 0
I might have to swap bottom backplane.


Anyway can you look at your harness
where the gray cable splits off into
a 6 pin and 10or12 pin molex and tell
me if it's hooked to anything,mines not.


On the road right now typing on phone


Thanks.Tim

[cartman765]

No The two pigtails not connected to anything just sitting there but other end goes to backplane and to speakers.

Dale

[stormrider]

Thanks for confirming Dale
Then that's the only source of power for the amp then
and I measure no voltage at p8 connection.

I will swap out the bottom backplane this weekend
funny for 24v source that's some mighty thin wire vs
any other machine Ive worked on.

rickhunter,

This particular machine is a little different from the normal alpha
although the wiring for amp board is the same without a backplane
behind it,I had to crop the pictures due to size here in messages.
I've had to repair a few of the burnt boards like you mentioned though.
Anyway here is a better picture of the amp board with no backplane.

 

[rickhunter]

Oh, ok.  When i get back home tomorrow I will look at my transmissive 5 reel machine.  I have one as well and will look at how it is connected.

[stormrider]

Oh, ok.  When i get back home tomorrow I will look at my transmissive 5 reel machine.  I have one as well and will look at how it is connected.

Hi Rick,

That would be great,as stated above I only see one source
for the power at P8 24v on lower back plane.
I did take a reading and got 0volts so it's not getting power

Looking at another alpha which is non transmissive
at P8 connection I did read 24v but those alpha's have the pigtail
harness connected to the upper board marked audio power.

So I'm hoping to swap the bottom back plane later today
or tomorrow also noticed 3 blue caps below P8 although not bulged
might have a look at those once board is pulled.

Thanks.Tim

[stormrider]

Pulled back plane found FB1 above P8 blown.

Installed new back plane now have 24volts coming off 2 pin connector
still NO sound,went into sound setup slider moves with no sound
tap on mixer settings shows game volume pegged on 10 can't adjust
and external volume does adjust.

Sound card pulled and tested in another machine and works
at a loss now.

UPDATE: Success finally have sound 

Pulled molex behind sound card amp found partially
burnt wire,repaired and all is good.

Another lesson learned..