Solved Neo-Geo 4 Slot no sprites

[Georgian2]

Hello,
Here I have this 4 lot neo-geo with no sprites. I don't have mucx experience mith neo-geo so I don't know where to start. I patched some NEO-253 on the top board and it brought sound and fixed layer back to life. I have activity on other neo-253 that are used for sprites. unibios and diagnostrics bios show no ram error.
I can't probe much on the bottom board becouse of the top board and without top board it won't make much sense, right?

Could the NEO-ZMC2 be faulty here?

Thanks a lot.

 

[Retroman839]

Yeah I want to probe z80 and Yamaha sound chip but I guess
It won’t be functioning fully without top board and cart running ,


Being a two board sandwich don’t help much does it !

 

[Georgian2]

Original BIOS boots without the top board but unibios won't. It stays at black screen. Diagnostics bios boots with or without top board and gives no errors.

 

[Retroman839]

I have a board with a bad
Neo zmc2
Games play no sprites…

I did have jail bar sprites ..
Tried to reflow the chip
Neo zmc2. F****led it

I still need to suck some solder out from under the chip that’s bridging legs ..

Since then same symptoms as yours ..

So maybe a bad ic or cold solder but yeh worth at look at that one

 

[Georgian2]

It dose look just like mine. Only static text. I'll swap it tomorow.
Dose your show the neo-geo logo on top of bootscreen with the unibios?

 

[Retroman839]

Leg off pad or legs touching

 

[Retroman839]

I will pay you to swap mine
Can Chuck you a couple spares 1 slots

 

[Retroman839]

I will pay you to swap mine
Can Chuck you a couple spares 1 slots

Mine I think is beyond !
I cannot get the solder out that went behind …

I tried with iron and solder sucker together

 

[Georgian2]

View attachment 36395

Mine I think is beyond !
I cannot get the solder out that went behind …

I tried with iron and solder sucker together

Put a lot of flux and a lot of solder in that spot. You need a lot of hot solder there. Hold the board in an angle so it all drips down.

 

[Georgian2]

View attachment 36395

Mine I think is beyond !
I cannot get the solder out that went behind …

I tried with iron and solder sucker together

Also you may find it a lot easyer to remove such ICs by using some of that low temperature solder. It stays wet a lot longer and gives time to heat it all around the IC.

 

[Retroman839]

Just got some good flux in solder

 

[Retroman839]

Cleaned it out better but couldn’t get it totally

 

[Retroman839]

But check it out


Current state

 

[Georgian2]

It's fucked up.

 

[Retroman839]

I don’t know ..
But that chip def Controlls sprites

 

[Retroman839]

It's fucked up.

Are you asking me or telling me ?

 

[Georgian2]

I'm telling you )

 

[Ace`]

If you're melting dip switches and destroying custom chips you're doing it wrong. You should be practicing on junk boards before doing any more damage to boards that can be repaired.

 

[Retroman839]

Point taken..👍

Received it faulty
I have junk to work on and I intend to …

Temptation to reflow got the better of me ,

Chip was showing jail bars when I got it

 

[Ace`]

I'm not trying to be mean, we all started out like this. That custom chip could be saved with a lot of time and work, but it was years before I was comfortable working on surface mount stuff.

The right tools, watching some youtube videos and some practice will go a long way, not sure what iron you're using but a temp controlled one and a few different tips would help a lot too.