28pin MASK to 32pin Eprom problem. (27C010 ???) * SOLVED *

[bytestorm]

Hi!
I wanted to make a repro of Duck Tales 2, and used Silent service as donor.
But When I read the guides on how to use 27C010 (32pin) no one mentions that it actually doesnt fit.. only 28holes in the pcb..
And I read somewhere here that bent up pin 1,2,24,31 something, but that doesnt work for me, and what about pin 32??

I used AM27C010 for the project.

Could anyone shed some light on this?

UNROM pcb. both SCN games so it should work, but I only get confused about wich pins goes where since i find different info on different forums ;(

Please

[80sFREAK]

pin 32 is +5V

[bytestorm]

Yes, i had to bend pin 32 also and bridge pin 30 and 32 with 5v. Pin 1 and 31 is floating.
Pin 2 to hole 22 ( but here I wonder if hole 22 is 22 for 28 or 32 pins pcb)?
Pin 24 to gnd ( but same here... Is this calculated for a 28 hole pcb or 32?)
I only get white picture ;( unrom mapper 2 so it should work ..

[infiniteneslives]

NEVER leave input pins floating. Without taking the time to look at the datasheet I'm guessing those are Vpp and /WE. You NEED to tie /WE to Vcc (5v) and Vpp doesn't matter (either gnd or vcc) but NOT floating.

I recommend discussing pin names and hole names vice numbers. The references for the 'hole' name is available on this site and the pin names can be derived from the data sheet. Match those up properly.

[bytestorm]

NEVER leave input pins floating. Without taking the time to look at the datasheet I'm guessing those are Vpp and /WE. You NEED to tie /WE to Vcc (5v) and Vpp doesn't matter (either gnd or vcc) but NOT floating.

I recommend discussing pin names and hole names vice numbers. The references for the 'hole' name is available on this site and the pin names can be derived from the data sheet. Match those up properly.

fixed, but still white screen.. what else could there be? i read in another thread that :

""
UNROM to UOROM on Konami board
Bend up eprom pins 1, 2, 24, 30, 31, and 32.
Bend up MC74HC32 pin 3.
Solder pin 1 to hole 14.
Solder pin 2 to hole 22.
Solder pin 30 to MC74HC32 pin 3.
Solder pin 32 to hole 28.
""

Since silent service is indeed a konami cart with 28pin eprom, is this the way to go?

But pin 30 on the 27C010 is NC...??

[infiniteneslives]

32 pin is fine. We can't really help you much from here. The only thing I can suggest is what I've said previously.

The references for the 'board hole' name is available on this site and the pin names can be derived from the data sheet. Match those up properly.

If you actually take the time to go through that excersize you've got a fighting chance with your current board. Your other option is try again from scratch.

Datasheets and nes rom pinouts are your friend. Post of this pin # equals this hole # are prone to failure.

[bytestorm]

i think i found my misstake now.. i will get back to this thread when i get home and test!
When i made the picture below it all became clear.. i hope

[proveaux]

Bend up pin 1, 2, 24, 31, and 32.
Wire pin 1 to pin 30, 31, and 32.
Wire pin 2 to hole 22 (the one under pin 24)
Wire pin 16 to pin 24

Believe this is correct for UNROM.
Will check when I get home.

[bytestorm]

Fixed! I did indeed miss to Wire pin 2 to HOLE 22 (the one under pin 24). i had it wired to pin 20..

now it works! thanks all!

[infiniteneslives]

Well its good to see you took my advice and it worked out.

I think I'll just bookmark this page now, and we can send everyone here instead of trying to have a this pin # equals this pin # discussions over and over again...

[drk421]

I'm noticing the flaws I wrote in that doc years ago.

I originally wrote it as a reference so I wouldn't have to re-figure things out every time I was modifying a board. Ugh... Sorry to haunt this board with that horrendous thing.

[infiniteneslives]

I'm noticing the flaws I wrote in that doc years ago.

I originally wrote it as a reference so I wouldn't have to re-figure things out every time I was modifying a board. Ugh... Sorry to haunt this board with that horrendous thing.

I've never found any significant flaw with it. Some things with /OE /CE and such get a little confusing, but you're pinout matches the actual wiring of the PCB from what I've found which is really what a guy needs when doing something like this. It's the best reference I've seen to send people too for NES mask ROMs and I certainly learned a lot with it when I started things a couple years back.

[SnoopKatt]

Quick question: I'm doing something very similar, except I'm putting on a 27C010 onto a 28 pin CNROM board (both CHR and PRG). I read through the pinouts, and I read through this topic. It looks like almost everything matches up if I scoot the chip up and directly line up pin 16 with hole 14, and pin 17 with hole 15. If I use some wire to connect pin 1 to hole 1, and pin 32 to hole 28, it seems to line up with the diagram. However, there are four floating pins: 2 (A16), 3 (A15), 30 (NC, guessing it doesn't matter), and 31 (PGM). Should I just connect those pins to ground, or can they stay floating?
Thanks!

[infiniteneslives]

NEVER leave input pins floating.

Ground them out tie to Vcc as appropriate. (depends on the pin function and how you program the EPROM)

[SnoopKatt]

NEVER leave input pins floating.

Ground them out tie to Vcc as appropriate. (depends on the pin function and how you program the EPROM)

Gotcha, thanks!