Espgaluda 2 sprite issue

PCB problems and fixes
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gozaimas
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Espgaluda 2 sprite issue

Post by gozaimas »

I have a minor issue with my Espgaluda 2 board - one frame during the character's 'charge up' animation appears to be glitched and showing weird. It's the only issue across the PCB - everything else renders perfectly, but it's still something I'd like to get fixed if possible.

Is it likely to be a capacitor thing, or something more serious?

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Last edited by gozaimas on October 4th, 2021, 2:32 pm, edited 2 times in total.
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nem
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Re: Espgaluda 2 sprite issue

Post by nem »

My guess it's a corrupted rom.

@buffi is the expert here.
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Re: Espgaluda 2 sprite issue

Post by buffi »

Yeah looks like a block on U2 has probably gone bad.
Can possibly be fixed through jtag by moving data away from the block thats gone bad but its a bit complicated

Otherwise just burn and solder a new U2 rom.

I guess this is the board that was on YAJ recently?

This one that is:
https://page.auctions.yahoo.co.jp/jp/au ... 1005199728
Last edited by buffi on October 4th, 2021, 9:49 am, edited 1 time in total.
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Re: Espgaluda 2 sprite issue

Post by buffi »

Basically, assuming it's a bad U2 (which it probably is), your options are:

Option 1: Replace U2.

Preferably locate a K9F1G08U0M and burn that with the rom from mame (first check that it doesnt have any bad blocks, otherwise you will have to do some... stuff)
... or patch U4 and use any other NAND flash that fits, see:
https://github.com/buffis/cv1k_research ... eplacement

This is not super hard, but requires a flash programmer and a NAND without bad blocks, unless you want to **** around with the bad block table and make changes to u2.



... or do it the EXCITING way

Option 2: Fix through JTAG without desoldering

The TL;DR is:

- Dump U2 (takes 72+h)
- Align blocks in dump with the clean dump in Mame (strip bad blocks, use table in block 1, page1)
- See if some block not marked bad in your dump is in fact bad
- Make a new bad-block-table in page1, where your newly bad block is also marked as bad
- Move all data away from that block
- Reflash using JTAG (takes 72+h)
- Hope it works? I've never tried it, but should!

Jtag info on:
https://github.com/buffis/cv1k_research/tree/main/JTAG

The scripts in:
https://github.com/buffis/cv1k_research ... xtractData
can be used to look at the sprites of your dump.

This is pretty complicated, but if you can dump your U2, I can probably help modify it to mark the block as bad. That way you just have to dump and reflash it yourself.


Option 3: Just accept it glitching I guess?

Easiest!
Learn to live with it :(
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Re: Espgaluda 2 sprite issue

Post by nem »

I root for the EXCITING WAY!!
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Re: Espgaluda 2 sprite issue

Post by buffi »

It's probably one of these spritesheets that are in a bad block (havent checked in mame yet, but looks right).


So JTAG dumping blocks where assets 195->198 lives and verifying the data there should be sufficient to diagnose if the issue is in U2.
Easiest fix if a block is bad is to just pick an empty block at the end of U2, write a copy of any assets there, and then remap any data touching the bad block in the initial index.

That way there's no need to do a full dump/write.

I've offered to have a look at the PCB.
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Re: Espgaluda 2 sprite issue

Post by gozaimas »

Thanks so much, Buffi. More soon!
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Re: Espgaluda 2 sprite issue

Post by buffi »

nem wrote: October 4th, 2021, 11:46 am I root for the EXCITING WAY!!
EXCITING it was. I did a writeup of the repair on AP.

https://www.arcade-projects.com/threads ... tag.19108/

Turned out to work exactly like I hoped
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Re: Espgaluda 2 sprite issue

Post by yosai »

Impressive work and an excellent write up. Thanks for documenting all of this. :awe:
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Re: Espgaluda 2 sprite issue

Post by geotrig »

excellent work buffi and exciting stuff indeed ,although your write up seems to have gone bad as there is a lot of gibberish the futher i scroll down and read ;) :awe:

top stuff :thumbup: :thumbupright:
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Re: Espgaluda 2 sprite issue

Post by thegreathopper »

Just had a read, excellent work.
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Re: Espgaluda 2 sprite issue

Post by nem »

buffi wrote: October 15th, 2021, 7:34 amEXCITING it was. I did a writeup of the repair on AP.
AWESOME :awe:
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Re: Espgaluda 2 sprite issue

Post by gozaimas »

Yeah, just to add my thanks to buffi for doing this experiment on my PCB. It was a little nerve-wracking, but thankfully worked perfectly. Fingers crossed that the chip in question stays healthy for a decent amount of time to come. What a wonderful community!
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Re: Espgaluda 2 sprite issue

Post by buffi »

Yeah, glad it was fixable like this.
Was pretty sure it would work, but was nice to verify that in practice as well :)
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