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ghantz

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Jun 28, 2019
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Hi,
I bought a board of mk2 but with my blast city I can not hear the audio.
The problem it's that my jamma connector don't have - 5v it's correct?
There is an adapter to resolve this problem?
Regards
 
Than I connect this converter between mk2 board and jamma of my blast?
 
Than I connect this converter between mk2 board and jamma of my blast?
Just like this...

20191112_174721.jpg
 
I have received this negatron but I don't hear anything
Why?
 
Ok, have you measured. Does it work? Does the board get -5v?
I know my Negatron has a small adjustment pot as well for the voltage
 

It's correct this screen?
I can't hear anything, no sound only background noise
 
Have you checked-5v?
I assume if that is not present all roms show up as bad
 
with a multimeter, place the black lead on ground (pin 1 or 2) and the read lead on pin 5
 
Jamma_pinout.png


The display is showing you +5v from pins 3 and 4. You need to measure -5v from pin 5 using a multimeter.


Negatronbig.jpg



Mine also has a small adjustment knob. This photo shows you the small gold knob near the “adjust” label.

Also I would adjust your +5v power so the meter reads 5.07v or so.
 
heads up. sometimes the cap by the back of the audio amp heatsink will go bad from the heat. if that cap is bad you will also get no audio even when you do get -5v to the board. the phillips caps that williams used were crap and commonly are dead at this point in time.
 
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