MK2/NBA JAM sound problems...

shilmover

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Can anyone point me as to where to start? I know these fail regularly... Someone must know... :)
 
I dunno... I have gotten lots of PMs telling me that they have the same boards with bad sound...

The problem on both my boards are that there is no sound... zero... nada... zilch... sound :)
 
very good. what happens when you go in test mode, the Sound Test?

does it say something like "SOUND IRQ NOT FUNCTIONAL" or whatever?

I'll be able to tell you the next step then..
 
well the reason I ask, is cause on my MK2 board the sound wouldn't work and would tell me like SOUND IRQ NOT DETECTED and I went over my cabling like 50 times, and checked voltages, and everything was fine.

it turned out to be a rom issue instead. had to reseat EVERYTHING.

why a software issue would cause a hardware problem like that, is a mystery.
 
Both state:

"Sound IRQ Detect Functional"

Power cable is there for both... I will check voltages again...
 

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Tested the voltages. At the header pins on the sound board...

MK2:
+5v is actually +4.83v
-5v is actually -5.6v
+12v is actually +11.06v

NBA JAM TE:
+5 is actually +4.7v
+12v is actually +10.94v
 
you need more juice, sir.

whatever your PSU's +5 is set at right now, seriously, turn it up like .3V lol you want your +5 to be close to 5.10-5.15, and your +12 needs to be way higher. your low +5 is probably the reason your -5 is a little high.

then power down and try again.

you're probably not getting sound cause the +12 is low. on my MK2 the +12 was at about 13.4 (cause the switcher doesn't regulate that)
 
you need more juice, sir.

whatever your PSU's +5 is set at right now, seriously, turn it up like .3V lol you want your +5 to be close to 5.10-5.15, and your +12 needs to be way higher. your low +5 is probably the reason your -5 is a little high.

then power down and try again.

you're probably not getting sound cause the +12 is low. on my MK2 the +12 was at about 13.4 (cause the switcher doesn't regulate that)

I will try, but I am not sure I can get any more juice out of the power supply...
 
supply

If you cannot get more juice out of the power supply the shit can it right now.
With the power off move you +5 adjustment on the power supply and move it to the increased end of stroke and see how much it moves and then move it back to where it was. If it did not move that far then someone increased it in the past as it was getting weaker. Now it may be at its lifes end but if caps in the power supply and other components decide to work properly for awhile then the voltage will increase way up and could blow some ic's. voltage pot should be around half way or so not mostly towards one end.
I have had bad rams and roms cause sound problems.
 
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