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Namco NA1/NA2 Repair Tips

I can't speak to the specific nature of this particular board- but IIRC you can buy a namco kick harness connector so you wouldn't have to solder anything direct to that board. (That's how I jumped out 3p/4p a long time ago).
 
ok
so before I start complaining there is no sound I will try to check sound from headphones pins
thanks
 
"Single" correct, as opposed to the "double"?
 
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Yes, no excuse at that price!
Here's what a average one looks like, notice the conductor is brown / black from all the capacitor damage and the base has missing carbon.
 

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As soon as I recapped the volume increased a lot but the potentiometers are quite noisy when you move them and seeing your photo let me only hope to recive the new ones ASAP :D
 
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I think that my working NA2 doesn't output any audio from the headphones pads, I've already ordered new potentiometers (thanks to @Hammy) and a couple of Mitshubishi M51568FP that from my research should be the headphones amplifier. Does anyone had a similar issue?

Can the issue be somewhere else (since all this parts come from china I prefer buying every possible part in advance rather than wait at least 20 days every time)? I've followed the traces from the connector to the amp (there are only some passive components) and I think that after the amp the traces are going directly to the sound chip or the other amp (?)

Obviously it's not a big issue since the mono audio from the jamma is working fine, so I'd prefer leave it as it is rather than risk of breaking something, but this 2 parts are quite simple to swap in my opinion :)
 
I want to share this little repair log since I was finally able to fix my headphones audio on my NA2.

First thing I swapped the potentiometers with the ones suggested by @Hammy and the old ones were very very rusted. Unfortunately with the new potentiometer the HP audio wasn't still back.

Next step I was panning was to replace the headphone amplifier. Since is very difficult to desolder components with some dirt while I was preparing the desoldering process I started to check every trace going to the amplifier and I found this:
PHOTO

After fixing it the HP audio was back to life but only on the right channel:
PHOTO

After a closer inspection I've found a disconnected resistor near the potentiometer:
PHOTO

Fixing the connection didn't help but when I measured the resistor I wasn't able to read any value.
After changing the resistor with a new one the left channel came back to life!!
PHOTO

And again as @Hammy suggested after recapping the board is highly suggested to change potentiometers as they hide a lot of rust
IMG_20201224_082541_544.jpg
IMG_20201224_082537_061.jpg
 
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sk8er000 said:
I want to share this little repair log since I was finally able to fix my headphone audio on my NA2.
Click to expand...
Nice work there! Sad they are all in this condition. As said before, the full PCB needs schematics.

I have some more info too, Clock comes out of custom 214 into LS04 @ 1L and then to the CPU.
If clock is not going to the LS04 but going into the 214 ... it's RIP 214? :(
I think the 214 also controls the main reset line to the CPU also.
 
Hi all I'm late to the party.
I got a NA-2 type pcb that is Numan Athletics that I've not used for years when it was working fine.

When i finally got a chance to play it, it did not work at all, does not boot and sometimes i get a full blank green, black, and blue when i fire it on. By research here it seems that the possible problem is the MB3773 "Watch Dog Chip?" or the 2.2 uf 35v capacitor.

I ordered both parts just in case and i really want the game to work again as it did back then. So strange that it was dead even when i take excellent care of my jamma games...
 

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yeah that C5 looks toast.

you should REALLY consider re-capping the whole board. No matter how well you "take care" of these boards the original capacitors WILL LEAK and WILL eventually destroy traces to the point where the board is irreparable. the only way to avoid this is to remove the shitty old caps, clean all the garbage residue off of the board and install good new caps.

I've owned about 15 Namco NA boards and literally literally 100% of them I've had to recap as all of them eventually stopped working and had deteriorated audio. It's way worse than another other system board I've ever had. the good news is that all but ONE of those 15 boards I was able to revive back to like new function. So if you catch it early enough it can be saved.
 
twistedsymphony said:
you should REALLY consider re-capping the whole board. No matter how well you "take care" of these boards the original capacitors WILL LEAK and WILL eventually destroy traces to the point where the board is irreparable. the only way to avoid this is to remove the shitty old caps, clean all the garbage residue off of the board and install good new caps.
Click to expand...
Thanks for the information friend i was really stumped why this happened.
This type of PCB reminds me of the ones from Sony. I hope this don't happen too soon on my NB-2 being Mach Breakers.
 
I've heard of people having failing/leaking caps on NB2, as well as system 12 but I've never actually experienced it on any of my boards.

best thing to do is to just keep an eye on it... if you see what looks like the board is "Wet" or has a residue on it, or the solder joints around the caps look dull and tarnished like the one in your picture of C5 above... those are signs of leaking caps and you should strive to replace them and clean up that residue with IPA as soon as you can.
 
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