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Namco 246 burned out Diode

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StreetSmart

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I do have an issue with a namco 246 and i know exactly what it is...I just can't source the diode part number ( value's )
Here is a pic of the diode i need. (D5)

If anyone knows where i can order this that would be great.

This is a pic of my other working board.
namco 246.jpg
 
You can also solder a regular leaded diode of the same specs if you have a hard time finding the smd ones.
 
Since that diode blew, the board was either subjected to overvoltage or polarity inversion. Before powering it up I would check all power regulators and the 5V stuff on the NAMCO board. (Very unlikely that there's been any damage on the PS2 stuff as they run on 3.3v, 2.5v, 1.8V and 1.5v)
 
I could be wrong but that looks like the JAMMA io board- I've seen a lot of horrible looking io boards where the power clearly isn't straight or something and arcing is evident- or in cases like this, blown components...
 
That particular diode is connected in a way that it suicides if the board is feed more voltage than it's threshold value (6.5v) or if the board is fed reversed polarity. The surge of current is supposed to trigger a short-circuit protection on the power supply or blow a fuse on the cab. With the ultimate goal of protecting all the stuff around it.
 
I'm the one that blew it. I was trying to hook a pc atx power supply, basically i put 12v in the 5v then it shut down immediately...
I was thinking pc power colors (12v yellow 5v red) instead of jamma color coding (12v red yellow 5v) so yeah,I fried that diode it was voltage overload.


It does play,just that the sound is all screwed up....so i went ahead and got a Sharp PQ30RV21 and 6.2v 5w zener diode


I'll see if that will fix it up.

 
Arcadesupergun said:
I'm the one that blew it. I was trying to hook a pc atx power supply, basically i put 12v in the 5v then it shut down immediately...
I was thinking pc power colors (12v yellow 5v red) instead of jamma color coding (12v red yellow 5v) so yeah,I fried that diode it was voltage overload.


It does play,just that the sound is all screwed up....so i went ahead and got a Sharp PQ30RV21 and 6.2v 5w zener diode


I'll see if that will fix it up.
Click to expand...
Yes. People should always replace the protections when they trip them. Lest the mistake happens again.

There is a Cirrus logic DAC chip on the PS2 board (COH-31100) but I don't think that's affected. There are analog amps on the NAMCO board and you might want to have a look on them. A good test perhaps would be connecting the RCA plugs to a regular stereo of amplified speakers and see if the sound is screwed at that point... The Sharp chip is a 3.3v regulator. You should maybe try measure it's output before trying to replace it.
 
l_oliveira said:
Arcadesupergun said:
I'm the one that blew it. I was trying to hook a pc atx power supply, basically i put 12v in the 5v then it shut down immediately...
I was thinking pc power colors (12v yellow 5v red) instead of jamma color coding (12v red yellow 5v) so yeah,I fried that diode it was voltage overload.


It does play,just that the sound is all screwed up....so i went ahead and got a Sharp PQ30RV21 and 6.2v 5w zener diode


I'll see if that will fix it up.
Click to expand...
Yes. People should always replace the protections when they trip them. Lest the mistake happens again.
There is a Cirrus logic DAC chip on the PS2 board (COH-31100) but I don't think that's affected. There are analog amps on the NAMCO board and you might want to have a look on them. A good test perhaps would be connecting the RCA plugs to a regular stereo of amplified speakers and see if the sound is screwed at that point... The Sharp chip is a 3.3v regulator. You should maybe try measure it's output before trying to replace it.
Click to expand...
When i receive the items I'm going to dig in lol

Thanks for the info
 
Didn't work same sound issues I'll make a video of it in a little bit. also in the pic FL38 what filter is this and where can i get it?
 
What makes you think the filter is bad? How are you troubleshooting the sound circuit?

The filter, in its simplest form should just be an inductor, a cap and a resistor. I dont think I have ever seen an inductor go bad. Usually other components fail before an inductor winding does, unless the the windings were compromised somehow.
 
I've seen those filters blown and to 'fix' it you just join wire from one side to the other.
not sure what they actually 'filter'. maybe they filter bugs or something ;)
 
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