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TheDeath

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Following what @twistedsymphony was talking about repairing this boards, i was wondering if there's something else to be known on these.
Changing SMD caps and MB3773 IC + 2.2uf 35V cap (just above it) is crucial.
How about reflow the asics that got oxidation by the caps? How can you clean that mess? I've heard that Lemon Juice or Winegar can do the job (almost) in few hours but i'm not sure about that.
There's something else?
I acually got 3 of these, 2 from a friend and one being mine if all repaired as a favour. They won't boot and i already saw tons of corrosion and disconnected pins in the asics.
What's your suggestion?
Thanks
 
How about reflow the asics that got oxidation by the caps? How can you clean that mess? I've heard that Lemon Juice or Winegar can do the job (almost) in few hours but i'm not sure about that.
The way I clean oxidation is I go over it with denatured alcohol to remove any lose particles then I cover the area with liquid flux and heat it up with hot air or a soldering iron. then go over it again with alcohol to clean up the flux. Sometimes repeating this process.
 
I've ordered a set of smd caps (in case of anything) ... but on my board, the previous owner , seems to take care of them ... at least , few of them was replaced and are reflow tracks on the volume pot.
 
The biggest repair tip on namco is to avoid them in poor condition. Once the corrosion has set into the tracks under that chip, it's over.

Damn.. i'm scared to do so, but i must :/
I've bought some oxide remover for metal on Amazon, i'll give it a bath before piggyback the customs.. hope this is gonna help me somehow
 
The problem is rot where the track goes into the solder mask under the chip. if you look careful there's lots of hairline cracks.

Putting 'fix wire' under this chip makes it uneven and then the legs don't line up.
 
The problem is rot where the track goes into the solder mask under the chip. if you look careful there's lots of hairline cracks.

Putting 'fix wire' under this chip makes it uneven and then the legs don't line up.
Yeah, unfortunatly these asics are the one with tiny spacing. I have deal with this s**t alot with Konami 05550 or DataEast tiny rat poop 223, i hate them so much.
Only thing to do is track down all the points and eventually lift pins/wire them with awg30 where they should go. At least is something but it's a pain in the butt
 
Data east 233 and raiden 2's here at the moment :D
Magical cat is another good one. Lucky the pads on that don't get corrosion!

Changing the chips is fine but when there's a high number of busted tracks it's too much.

If you succeed, there's plenty of them available in this state and this PCB is in super high demand at the moment haha.
Good luck :)
 
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Can you guys help me with the pcb layout? Maybe it can help for future needings, i would like to identify sram usage in the mobo.
No 1 i suppose it's the Bios, No7 it's the MB3773 reset ic.
What about work rams, color rams, and so on? wich are wich?
Thanks for the help
 
I did a video on the pallet ram, can't remember from memory exactly.

for the bios C69 is na1 and C70 is na2.
 

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Sadly i just can't get these bastards to properly work.. after changing the MB3773 and work rams, game booted random, something displaying proper graphics and sometimes it doesn't.
The other one boots up black with top-board and random full screen color without.
I don't understand why after changing the MB both Halt and Reset keeps to be LOW no matter what. I followed until i could traces and din't find suspicious.
I'll probably try to check those 62256 in that top package that i don't even know the name of it, but other than that, this smd boards are horrible when leak eats them, it's almost impossible to get it throught... :(
 
The problem is in the connections of the surface mount chips, 1 bad track it will crash immediately.

The way to repair them is map out one and get the schematics, followed by checking all 300+ pins on EACH custom.

OR remove the customs, clean and patch PCB and then refit customs.
The customs are not bad, it's just the connections.
 
The problem is in the connections of the surface mount chips, 1 bad track it will crash immediately.

The way to repair them is map out one and get the schematics, followed by checking all 300+ pins on EACH custom.

OR remove the customs, clean and patch PCB and then refit customs.
The customs are not bad, it's just the connections.
Meanwhile i'm just doing it, i'll share a picture of the connetions underneath the 2 customs. It might be needed to someone and prevent the hassle to desolder this bastards
Big picture here: https://ibb.co/NCWkdj1
20200529-100602.jpg
 
Nice 30% there ;)
Now to test all the tracks, get all the old solder off and clean the pads.
If you have microscope it makes it faster by eye.

I got to the checking round and stopped, never refitted and tested ;)

This is the same motherboard model from above (na2)? There is several model numbers / versions.

Edit, my one stripped is an NA1, looks same under the 215 chip. I never removed the other.

PS. 214 = address mapper logic, 215 = GFX chip (with the DMA functions from the CPU and more)
 

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There is 2 Ver's of NA1, my pic / vid above is the regular.

There's also a version with NA2 silkscreen and possibly more?
AFAIK the differences are in the video output section and bios but there's maybe others.
 

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Made little progress here with the second board, the NA2.
Unfortunatly i think i fkd up the other one, gluing the customs was a terrible idea (i did that because i was sure about the reflow, but apparently it wasn't somehow). Unfortunatly i'm not able to solder them back, i cannot remove the epox without ripping pins (lesson learned btw).

Funny thinking that this second board act the same as the other one, after palette/ram check it reboots in loop.
When i changed the main work rams (on the epoxy one) the game booted fine for a while and then it keeped getting worst and worst until a solid black screen.

I'm afraid of doing the same here (changing work rams), but i assured my self the customs are properly soldered and NO glue here this time.
I have probed the data pins of the work rams and they seems to be having a good activity but it's hard to tell just with that, mostly because the same was doing the other one.
I did reflow anything in the caps area nearby, looks shiny and good to me.
 
Hey guys.

I'm working on one of these boards right now. It initially wouldn't boot but changing that 2.2 mf cap fixed that. Then I had no sound so I figured I'd recap the audio section of the board. That "kinda' fixed it. I have sound now but only in one VERY SMALL spot on the pot. :( Yeah, the volume pot is bad.

Anyone have any idea where to find that pot? Or even know the values?
 
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