Question about surface mount caps for repairing X-Men sound chip

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Question about surface mount caps for repairing X-Men sound chip

So today I fired up my 4 player board and while it still had sound, some electrolyte began leaking from a few of the caps on that damn custom chip. I had done a little digging into the issue on a spare 6 player board and I can see that it wouldn't be too hard to switch out the caps. My question would be on the cap values. Here's John Robertson's page with the schematic for that chip.

Fujitsu_MB3722_Capacitors.JPG


It lists the caps' uF values but nothing about the voltage. Now the only thing I see for voltage to the chip is the vcc so am I correct that as long as the caps are rated for 5 volts I'll be ok? I've seen a few websites with these type of surface mount caps so finding them shouldn't be an issue. Also, I physically counted 10 caps on that chip and looking at the schematic I only see 9 labeled. It looks like in the upper right of the schematic there is a cap that's not labeled in value. Is it the same as the 0.1uF cap to its left? What do do the stripes mean on the one on the right? So here's what I would say is my shopping list if I wanted to change all the caps while I'm at it. I may just change the few that I know leaked, but I want to be prepared.

Edit: A little google search turned up a post on RGVAC confirming that these need to be 12volts or higher caps. Makes sense given that it's sound related.

One 10uF 12v cap
Four 100uF 12v caps
Two 1000uF 12v caps
Tree 0.1uF 12v caps (Assuming I am correct about that last cap's value...the one in the upper right corner next to the other 0.1uF cap)

Any help is appreciated. Time to save these boards!

Edit: If anyone has any better methods than just a razor blade to remove that black coating on the chip, I'm all for it.
 
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John had a post somewhere stating that 16v caps (quite common) would be fine since there is only 12v in that area.

EDIT: I didn't read all the way through to realize you had figured the voltage part out.
 
John had a post somewhere stating that 16v caps (quite common) would be fine since there is only 12v in that area.

EDIT: I didn't read all the way through to realize you had figured the voltage part out.
Haha yeah my search fu finally paid off a little. Also I just realized that schematic is actually for the amp chip with the heat sink on it. What it must be showing then is all the different traces coming into it from that custom chip then.

Edit: My 2,000th post! :fest30:
 
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Ok cool document I stumbled across thanks again to Google. This PDF gives the cap values for this 054544 custom chip. I screwed up the one cap I've already replaced on a soundless 6 player board. I put a 100uF in for C7 when it should have been 47uF. Now 100uF would have probably worked had C6 been removed. I used a translation tool to read the Japanese at the bottom and it says 100uF is about equivalent to 2 47uF in parallel. This makes sense looking at John's page because he removed 2 of the 47uf caps and put a 100uf in their place. I think I'll throw a 47 in where I put the 100uF and cross my fingers that I didn't damage anything. If nothing I've learned a lot from this document and hopefully my other 6 player board, which is the original serial matching board for my cab, can be revived. Anyway, here's the document. Really interesting stuff and hopefully this helps out. I know a lot of X-Men owners and others would appreciate the info. I've submitted this to arcarc as well.

http://garakuta.homelinux.org/~nosuke/tsubo/files/misc/054544_memo.pdf
 
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Hmm tried a 47uF and no dice. Very possible other caps are bad so more investigating needs to be done. Progress at least. :)
 
great thread keep us informed of your progress. Any chance you could take pics of the progress? I have a Gijoe board with the same problem.
 
great thread keep us informed of your progress. Any chance you could take pics of the progress? I have a Gijoe board with the same problem.
Yeah I could take some pics. I don't consider myself a genius tech by any means but if it helps anyone I can. I do feel that people trying this repair is going to be more and more important. I hate to think how many other people are having sound failures and their only solution is to buy another board.

Final progress update for the evening. I ordered a bunch of each of the 3 values of surface mount caps from Mouser. Since my 4 player board and the original 6 player board need some attention, I figure I might as well have a bunch on hand. As for the board I'm using as a guinea pig...so far I've changed out 7 of the 11 caps with regular electrolytic caps (not pretty but it works for my first attempt at this) and no joy. I've checked for continuity from the solder pads to the legs of the chip and had continuity so I'm not suspecting bad traces at least with the ones I've changed so far. Lastly I decided to throw this board in my 6 player to make sure I wasn't missing a setting in test mode. As I did I noticed the board currently installed looks to have a problem with this chip too. :mad: Geez 4 X-Men boards and all have problems with this chip. At least the 4 player and currently installed 6 player boards still have sound, but for how long? :(
 
I hope this works.

Only thing I can tell you is I had sound trouble out of a Neo Geo one time. I replaced several caps, didn't fix it. Replaced several more, didn't fix it. I had to replace EVERY CAP, then voila it worked perfect. So you may still get it, after you replace all of them.
 
I hope this works.

Only thing I can tell you is I had sound trouble out of a Neo Geo one time. I replaced several caps, didn't fix it. Replaced several more, didn't fix it. I had to replace EVERY CAP, then voila it worked perfect. So you may still get it, after you replace all of them.
Yeah my next plan of attack is to just swap out those last 4 and see what I get. Nothing has smoked or anything so that's at least an okay sign. Just not sure why I'm not seeing any response from the board yet.
 
The biggest problem with those hybrids are those pesky trace on them. If the electrolyte makes it to the edge where the pins attachec then it'll mess up the connections between the upper and lower side of it.

There are custom ICs and other parts on the bottom side and if the connections between the 2 sides are messed up then it's just about impossible to fix those modules.

Does anyone have any dead modules AND some nitric acid to try to remove the conformal coating? It'd be interesting to see if the acid would just remove the coating only and not the traces. That would allow for a better way to draw out the traces and document the module.

RJ
 
The biggest problem with those hybrids are those pesky trace on them. If the electrolyte makes it to the edge where the pins attachec then it'll mess up the connections between the upper and lower side of it.

There are custom ICs and other parts on the bottom side and if the connections between the 2 sides are messed up then it's just about impossible to fix those modules.

Does anyone have any dead modules AND some nitric acid to try to remove the conformal coating? It'd be interesting to see if the acid would just remove the coating only and not the traces. That would allow for a better way to draw out the traces and document the module.

RJ

On the one I'm attempting to fix, I don't *think* the electrolyte has made it to the edge and attacked the pins, but I can't say for certain. The fact I've replaced the caps I thought were suspect and haven't had any change makes me wonder more and more if this board isn't a lost cause already. At least I had nothing to lose anyway since it wasn't working. These things sure are a pain in the ass. Thankfully not every Konami game used them. I mean I just finished a Simpsons restore a few months ago and at least with that game I don' have any concerns for it to fail.

I don't have any dead modules that are removed from boards unfortunately. I read in another thread that CLR was one way to remove the black epoxy without damaging the ceramic substrate. I haven't tried that one myself. I'd be happy to send a board your way if it would somehow help document these things. I have one 4 player and one 6 player boards that are working, but starting to show signs of leaking caps and another 6 player board that's soundless with one of those caps physically broken.
 
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I picked up some CLR last night per John Robertson's RGAC post about using it to remove the black epoxy. Hopefully this proves successful and I'll post what I find out. I'm also asking for input on the possibility that someone could somehow reproduce these things or find some kind of work around. I know there are a lot of people on here who could care less about X-Men, but I'm willing to bet there are more than enough fans of the game, let alone people who own the pcb's and cabinets that would want to see something done if possible. Beyond that other games like GI Joe use the chip or a variant of the chip like Lethal Enforcers. If it seems worthwhile to document the chip, I'll do what I can to find that person and/or get them a chip. Input from anyone on whether it's worthwhile to document the chip would be appreciated. It seems like to know if it's possible to do anything with it, documentation would need to be the first step. Unless it's impossible then I'd say anything is worth a try.
 
The biggest problems is documenting BOTH SIDES of the hybrid module.

Most people don't realize that it has chips on the bottom side - including a custom Konami chip. If the electrolyte reaches the edge of the board it'll keep the signals from going between the top & bottom sides as it eats traces and does its damage.

To properly document the chip will require the removal of the coating on both sides and removal of the chips on the bottom to follow traces that go under the chips.

Don't forget that there are resistors on the modules that are simply deposited carbon between traces. If the CLR eats those then you are hosed. Those resistors must be documented too!

It will be easier to document a destroyed module to get the bottom side traces mapped out than to try to removed and reflow chips on a repairable module. Too bad I already got rid of the 2 modules I spent so much time trying to resurrect. They would've been great candidates for that.

RJ
 
Bump to just share my attempt at repair. I received my order from Mouser so I have enough of these sm caps to do full cap outs on 3 modules. Tonight I decided to take a look at my original 6 player X-Men board. This one would be nice to get running, but right away I noticed it some electrolyte looked to have made its way to the pins on the edge. Damn it! :mad: If you look at the upper left of the hybrid in the pic below, you can see a few of the pins look to be corroded. I decided to just go ahead and remove all the caps and hit the thing with some denatured alcohol just in case it can be saved. Man it is indeed a bitch getting these things removed. Every single cap all I could manage to get lose was the cap body from the legs. I then had to remove the legs and go back and clean the solder pads which most had remains of the legs on. I was using solder wick since I didn't think my de-solder station was quite precise enough to get those small pads next to the caps. That stuff was a pain in the ass to get to flow also. Anyway, here's a quick shot of the board as it sits with all caps gone and the area neutralized.

DSCN0660.jpg


Hopefully by some miracle I can save it, but man this has been a pain in the ass working with these. If X-Men wasn't one of my all time favorite games I wouldn't mess with it. There's not really much choice I guess since more and more boards will have the same problem. I'm glad I took a look at my current 6 player board when I did. It too had some leakage but I hope that I've caught that one in time and can have an easy cap out to keep it running. I may take a look at that other 6 player board that I started replacing caps on already. Might as well give it a shot.
 
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BTW these caps sure have small leads to solder to. Maybe that's part of the reason the old ones were so hard to remove....that or some corrosion was causing it. I'm guessing there's nothing really special that needs to be done to put these new caps on. Just gotta get some solder to flow on the pads and that should easily hold those leads on.
 
That's just the nature of that surface mount stuff. I worked on a guy's home game system that had small little pads like that, it's a p.i.t.a. but I was able to do it. Just have the caps sit up a little higher so you can see what your'e doing!
 
The problem is 2 fold...

First, the electrolyte is causing oxidation and poor heat transfer to melt the solder.

Second, the ceramic substrate is wicking off the heat VERY quickly from the solder joint making it difficult to get it hot enough to melt the solder.

Put those 2 together and it's a bitch to desolder those caps.

The best method is to rip the caps off then take some small cutters or pliers and break the plastic base of the caps off to leave just the leads and exposed solder connections. At that point you have your best chance of desoldering the cap pins.
 
Ugh calling it a night on attempting to put these new sm caps on. I got 3 of them on but I'm struggling mightily. I'm starting to think maybe I should just go with plain ol' electrolytics on these....not sure I have the patience to screw around with these horribly small leads on the sm caps. A few things that I should probably invest in are a magnifier lamp and a smaller tip for my solder station. I probably need a lot more practice too, but between the small leads and getting the damn cap to even stay in the right spot I'm frustrated to the point I'll do more harm than good if I don't step away at least for the night.
 
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