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Author Topic: MV2F unknown soldering blob/bridge/thing...?  (Read 5689 times)

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snappleman

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MV2F unknown soldering blob/bridge/thing...?
« on: April 26, 2021, 10:13:16 pm »
Opened up my MV2F to give it a little cleaning today and saw this:



I got no idea how that got there, I've had this board since maybe late 2001? Been using it regularly since then, and I never noticed this. I did consolize this back in 2001-02 and swapped in a coin cell holder a few years later, but I wouldn't have soldered those pins together like that, even by accident. The board has been working perfectly with 0 issues for almost 20 years now, so it's seemingly not hurting anything... but I have no idea who did that and why. Is that some kind of old mod or repair I'm not aware of?

nexusmtz

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #1 on: April 27, 2021, 09:39:10 pm »
That looks like an unintentional solder drip. The middle pin is connected, but the ones on either side don't have any trace leading to them, so those aren't intended to be used. They might be getting a signal fed into them, but if it's having no ill effect, don't worry about it.

Have you tried just gently scratching it off with your fingernail? Drips/splashes usually aren't very strong.

snappleman

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #2 on: April 28, 2021, 12:40:52 am »
Yeah I tried scratching at it, it doesn't budge. What I also see when looking real close is what looks like a bar of solder in there, so it's definitely a drip someone got on it while tinning an iron. I'll just clean it up by soldering it off, but then watch the board inexplicably stop working  :D

Mike A

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #3 on: April 28, 2021, 06:48:56 am »
Be ready to open up a can of worms when you "fix" a board that is working fine.

If I had a vote in this matter it would be "no".

The board has been solid for 20 years of regular use.

Just pretend you never saw that glob.

Gilrock

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #4 on: April 28, 2021, 10:40:58 am »
That looks like more than a drip of solder to me.  If I told you to bridge all 4 of those pins and connect to that via you'd find out it takes a bit of work to tie that all together.

nitrogen_widget

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #5 on: April 28, 2021, 12:48:49 pm »
those chips are responsible for switching between cartridges on dual slot neo geo boards according to the wiki.

It also says those chips fail and have extra pins and those are used via jumper.
it could be a repair.

https://wiki.neogeodev.org/index.php?title=NEO-257#Pinouts

Gilrock

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #6 on: April 28, 2021, 02:37:15 pm »
Interesting.  I browsed the pinouts from that link and those pins look like they multiplex data lines from the 2 cartridges so I cannot see a reason to tie those lines together.  It looks like the solder crosses pins 12 thru 15 and those should all be independent.  If its really just a couple bits for the sprite data you might not even notice that its messing up the colors.

nitrogen_widget

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #7 on: April 28, 2021, 06:59:41 pm »
Interesting.  I browsed the pinouts from that link and those pins look like they multiplex data lines from the 2 cartridges so I cannot see a reason to tie those lines together.  It looks like the solder crosses pins 12 thru 15 and those should all be independent.  If its really just a couple bits for the sprite data you might not even notice that its messing up the colors.

yeah, according to what it said you wouldn't involve those however i really don't know.
what I do know is if it ain't broke don't fix it.

would hate to him back here with post about graphics issues after cleaning the solder off.

nexusmtz

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #8 on: April 29, 2021, 02:21:15 am »
If I told you to bridge all 4 of those pins and connect to that via...
I'd agree, if that were a via and not the pin 15 dot.

Gilrock

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #9 on: April 29, 2021, 11:01:55 am »
If I told you to bridge all 4 of those pins and connect to that via...
I'd agree, if that were a via and not the pin 15 dot.

Yep I noticed that was probably a pin marker when nitrogen provided the link.  I'd say its safe to remove it.

Howard_Casto

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #10 on: April 30, 2021, 02:32:41 pm »
I'm with Mike on this one... if it's working leave it alone.   There is a fine line between "mistake" and bodge wire repair.

Gilrock

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #11 on: April 30, 2021, 02:51:41 pm »
Based on the schematic for that chip there is no way its a repair.  One way to settle this argument.  I'll $20 if you have to reapply the solder....lol.

snappleman

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #12 on: June 23, 2021, 11:21:54 pm »
Sorry to bump my own dead thread from months ago, but I got a newborn in the house so I'm just now able to follow up! Soldering iron heating up, brb...


Aighhht, blob gone, everything works great!



Gilrock

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Re: MV2F unknown soldering blob/bridge/thing...?
« Reply #13 on: June 24, 2021, 09:00:29 am »
Yeah too late bro I already spent the $20