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AES 3-6 Stock With Graphical Glitches and Heavy Vertical Lines

Mobiusstriptech

Mobiusstriptech

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Hey All. I picked up this AES for my own personal unit and it has some graphical issues. I pulled the bios and popped in the diagnostic bios and it all comes back good. I also popped in a UniBios free version and ran the hardware test, no errors reported.

There is nothing obvious on the board that is jumping out at me it had definitely not been opened before. I tried the flex/pressure tests and there are no changes. Tried multiple carts and got the same issues. The only thing I can think of that seems similar is an issue with FIXD0-7 and the S ROM, but my issues are not present on health bars.

Also the issues do not appear on the main boot screen or the UniBios menu. The other thing I noticed is a diagonal scrolling effect across the screen and when the diagnostic bios is installed the screen becomes extremely wavy. Any thoughts are appreciated.

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Your problem looks like sprite related ONLY. So look for a faulty custom IC related with sprites (i.e. C Bus) from https://wiki.neogeodev.org/index.php?title=Category:Chips

NEO-B1 may be?

Or look for a faulty buffer or multiplexer on C Bus. I'm afraid I do not have AES expertise but lots of experience on MVSs. I once fixed an MVS 2 slot where neither diagnostics bios or unibios can detect and the culprit was some dead ports of NEO-257 customs. Generating exactly the same graphical glitches as in your case...
 
yavuzg said:
Your problem looks like sprite related ONLY. So look for a faulty custom IC related with sprites (i.e. C Bus) from https://wiki.neogeodev.org/index.php?title=Category:Chips

NEO-B1 may be?

Or look for a faulty buffer or multiplexer on C Bus. I'm afraid I do not have AES expertise but lots of experience on MVSs. I once fixed an MVS 2 slot where neither diagnostics bios or unibios can detect and the culprit was some dead ports of NEO-257 customs. Generating exactly the same graphical glitches as in your case...
Click to expand...
Still you seem to have a lot of knowledge.
I never use diagnostic BIOS, probably because when I started my repair business they weren't a thing and because they only detect "easy" faults.
Also there are so many different hardware in the arcade world you have to be able to troubleshoot on your own (no documentation, no diag tests, etc.).
 
yavuzg said:
Your problem looks like sprite related ONLY. So look for a faulty custom IC related with sprites (i.e. C Bus) from https://wiki.neogeodev.org/index.php?title=Category:Chips

NEO-B1 may be?

Or look for a faulty buffer or multiplexer on C Bus. I'm afraid I do not have AES expertise but lots of experience on MVSs. I once fixed an MVS 2 slot where neither diagnostics bios or unibios can detect and the culprit was some dead ports of NEO-257 customs. Generating exactly the same graphical glitches as in your case...
Click to expand...
I want to give credit where credit is due. For not knowing much about the AES, you are on the right track. It's definitely related to the sprite lines and the Neo-B1.

I reflowed the Neo-B1, no change. However if I apply pressure to the side where the sprite signals come in, then it changes. I was also able to get the issue to flip by pressing on the chip while reflowing all the pins. I don't know that it's the Neo-B1 itself, but I am suspect of the signal traces under the chip.

Thanks for giving me a better idea of where to look.
 
The diagnostic bios only tests RAM, BIOS< CPU and a few other functions. Smkdan (The creator of the d-bios) actually was going to create a cart/bios combo that would fully test the system including graphics but just needed funding, I haven't heard from him in a very long time though.

As for the graphics problem, I'd check the traces to/from the cart slot and the Neo-G0 as that's a common trace that goes bad because of "dust flaps".
 
Thanks for the tip. I will take a look at those traces as well as try direct connecting the sprite signals off the cart connector to the Neo-B1.
 
And the issue is solved. I will have to post pictures later. Pin 56 the GBD3 signal was open. The trace was broken underneath the Neo-B1. I had signal all the way up to the via that goes underneath the Neo-B1. Big thanks to yavuzg for pointing me towards this.
 
Great news! I'm glad that you've fixed your AES and glad to hear that you were lucky to not ended up with a faulty NEO-B1.
 
I was definitely convinced earlier today that it was the chip. Glad I checked again tonight. It's so weird that the trace is broken under the Neo-B1 and not on the bottom of the board or anything.
 
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