TLROM to TNROM conversion

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TLROM to TNROM conversion
by Harry Hardon on 2007-12-08 (#29207)
I saw some people who have converted Mega Man 4 (TGROM board) into Final Fantasy 3 (TNROM). They added a WRAM.

I didin't know that WRAM could be added in a board without it... So, I figured out that TLROM boards can be converted to TGROM by only adding a CHR RAM, instead the original CHR ROM (with some rewiring).

After converted to TGROM (with chr ram), that board could be transformed into TNROM by adding a WRAM, and bringing a wire to slot pin 56.

That part is easy, but, HOW to add a WRAM? An user have posted some pics in my other thread where he adds that WRAM. Anyone knows how to do this?

I'll post some pictures:
Seems he soldered WRAM and PRG ROM together. :shock:
It's a pirate Mega Man 4 converted to Final Fantasy 3.

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High resolution pictures: http://s9.photobucket.com/albums/a69/rocketzapdos/


Thanks!

by Lloyd Gordon on 2007-12-08 (#29223)
I was thinking of something like that but I ran into the missing WRAM connector pad on the NES cart connector problem. The pirate cart pictured seems to have all the missing cart connector pads.

by Bregalad on 2007-12-08 (#29227)
Quote:
That part is easy, but, HOW to add a WRAM? An user have posted some pics in my other thread where he adds that WRAM. Anyone knows how to do this?

That is pretty simple in fact you just have to flip the RAM chip and solder it on the other side of the ROM chip (exept for the enable pins who have to be bend up and wired directly to the mapper). The last picture shows this exactly. The hard part is to be sure each solder is make proprely and make good contact I guess.

Note that it's also possible to get 4-screen mirroring on a regular cart this way (by placing a flip-RAM chip below the CHRROM chip).

by peppers on 2007-12-08 (#29245)
when useing an offical cart dont you have to do some pinout adjusting?

by Bregalad on 2007-12-09 (#29251)
Right, however, if adress lines or data lines are exchanged on a RAM chip there will be no effect (as opposed to a ROM chip). There will be the need to wire some pins manually anyways, but not that many. (/CE, CE, /OE and /WE).
Also, if I were to do this I'd first rewire the ROM normally by cutting tacks and placing wires, and then solder the ROM/RAM on the already rewired pinout to avoid problems. Anyway, add RAM to an existing commerical cart without changing the ROM makes no sense.

by Harry Hardon on 2007-12-10 (#29296)
Thanks, that cleared up a lot. :)

But I've looked on NesDev document with mapper pinouts, and I noticied there are 2 WRAM CE, one in the pin 30, and another on the pin 41, as you can see below:

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On an orginal SRAM 6264, there's 2 CE too, but identified as CE 1 and CE 2:

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In the mapper's chip, both CE are the SAME? Or there's an order to solder them?

Thanks! :)


Lloyd Gordon wrote:
I was thinking of something like that but I ran into the missing WRAM connector pad on the NES cart connector problem. The pirate cart pictured seems to have all the missing cart connector pads.

Yeah, I have that problem too. I'll manage to glue a piece of metal there.
Hope it works. :)

by Bregalad on 2007-12-10 (#29302)
/CE and CE isn't the same thing. One is a positive and the other is a negative enable. In your SRAM diagram, CE1 is /CE and CE2 is CE, altrough it's a very stupid way to name them CE1 and CE2 wich made them undistinguable (and they look both positive that way, along with OE and WE wich are /OE and /WE).

by sdm on 2007-12-15 (#29568)
If you want FF3e cart, you can modifi any MMC3 cart into it.
http://nintendoallstars.w.interia.pl/romlab/nesram.htm
http://nintendoallstars.w.interia.pl/romlab/nesvram.htm

No need VRAM MMC3 carts like megaman4, just use any cart (also with CHR-ROM - just remove CROM, wire and solder VRAM 8KB) :roll:

Simple & easy... :wink:


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Harry Hardon wrote:
That part is easy, but, HOW to add a WRAM? An user have posted some pics in my other thread where he adds that WRAM. Anyone knows how to do this?
Thanks!

Solder it under PRG ROM or use wires ;)

Under PRGROM (like my MMC5 castlevania 3 cart with added SRAM):
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