None, just use your eprom writer software and specify an offset. write-up here:
https://www.arcade-projects.com/forums/index.php?threads/naomi-cart-repair-to-ikaruga.3998/
- Thread starter RealMFnG
- Start date
https://www.arcade-projects.com/forums/index.php?threads/naomi-cart-repair-to-ikaruga.3998/
ZERO_MILES
Enthusiast
SNK-NEO-GEO
Enlightened
I don't know the background or story on you know who but he converted 6 carts for me.. he got the job done. Some people are highly skills and choosing to protect their craft is not necessarily a bad thing.. look at it as a service being provided that no one on the market is currently providing..reach out to him and get it done them move on..
Big globs of glue and sloppy soldering, then blaming it on the end user when his conversions die and refusing to fix them is my experience with AMB. Not worth the hassle.
Someone will end up having to fix it down the line anyway. Get it done right the first time.
Someone will end up having to fix it down the line anyway. Get it done right the first time.
SNK-NEO-GEO
Enlightened
I see thanks for the clarification.. I have to open one of mine and provide pics and see.. the end result is that some else need to provide that service for the community.
XtraSmiley
Legendary
Please do, I’m curious if old habits die hard.
ZERO_MILES
Enthusiast
I emailed that guy a couple of times, no response, so I gave up. I hope someone else with good reputation can do it for me.
How the hell do your guys program MX26L6420? I've tryed, finally, some converts, and none of mine programmer actually support this eprom.
Can you just re-use/re-write the ones placed on the rom board? If yes, how?
Can you just re-use/re-write the ones placed on the rom board? If yes, how?
Not all programmers have an adapter for those chips, but many do. If you can't buy it for your programmer, you'll need to make your own adapter from MX26L6420 to 28FEW032 or similar.
https://docs-emea.rs-online.com/webdocs/04ee/0900766b804eeb92.pdf
https://docs-emea.rs-online.com/webdocs/04ee/0900766b804eeb92.pdf
I have fhe adapters, but none of my programmers actually have 26L6420 as a supported eprom (most sop44 got stuck till 26l800)... also, this is 8MB x 8bit and the one you posted is 4MBx8... don't get that
SNK-NEO-GEO
Enlightened
if you make your own adapter you can choose with a jumper if you want to program the lower 4M or higher 4M
Can you supply higher RES pictures please ? I would like to see the markings on the PIC chip and the main SMD devices.
Can you help me figure out how? I've heard it many times but actually no one explained how this works. I can just try with lower eproms but i don't know how to swap between banks
It's very simple. Let's assume that the chip that you want to read has 23 bits in the address line.
That's 2^23=8388608 (decimal) or 0x800000 (hexadecimal). Just take the higher address bit (bit 23) on the chip that you want to read and with the help of a jumper you connect it either to VCC or GND, that will force it to 1 or 0. So you can first force a 0 and read the first half (which is 0x400000 in size) and then force a 1 and read the other half (again 0x400000 in size).
Actually if you want, you can use 2 jumpers to replace 2 address lines and you will have 4 combinations (00,01,10 and 11) and you will be able to read a chip 4 times in size, by making 4 reads. Then just put together in the right order the 4 parts read and you're good.
That's 2^23=8388608 (decimal) or 0x800000 (hexadecimal). Just take the higher address bit (bit 23) on the chip that you want to read and with the help of a jumper you connect it either to VCC or GND, that will force it to 1 or 0. So you can first force a 0 and read the first half (which is 0x400000 in size) and then force a 1 and read the other half (again 0x400000 in size).
Actually if you want, you can use 2 jumpers to replace 2 address lines and you will have 4 combinations (00,01,10 and 11) and you will be able to read a chip 4 times in size, by making 4 reads. Then just put together in the right order the 4 parts read and you're good.
Cool, thanks Darksoft!
So let's say that i want to use a 26L6420 (64mb) and my programmer only got 29L3211 (32mb), should i get the higher adress (A21) and toggle between vcc and vpp in order to be able write 2 times on it, going for lower and upper bank? is that right?
SNK-NEO-GEO
Enlightened
