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PostPosted: Fri Jun 23, 2017 9:23 am 
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Hardware/nes specs:
So to start off I have a GQ-4x4, with the 16 Bit EPROM 40/42 pin ZIF adapter. (Not using the adapter atm) using USB only, no power adapter.
I ordered a bunch of Eproms, namely M27C512, AM27C010, M27C1001, and others. The ones listed are the ones I have in hand.
I have the CIC disabled(Pin4) on my NES front loader, and a Blinking light win installed. All other OEM hardware. Works with any original game I have.
Famirom for rom splitting to bin files.

Doing the work
I picked up a copy of Wheel of Fortune (Aorom) with a cracked case for cheap. I used http://bootgod.dyndns.org:7777 and found Jeopardy! (RevA) to be usable for a test run. Both of which only have a PRG to write. I used Famirom to spit out the .bin file of Jeopardy then imported the bin and used USBPrg (GQ-4x4 Eprom app) to burn an AM27C010 a 1m(128x8) chip. Did a blank check, wrote successful (I think). I'm thinking great, lets get the PRG off of the Wheel of Fortune and replace it with our freshly written AM27C010 with Jeopardy on it. Tested it and nothing, just a purple blinking screen. (Without wiring anything). Put the original Wheel of fortune PRG back on and test it, booted right up to the original donor game like a champ.

Confused am I doing something wrong
Puzzled I looked online and found docs online about wiring axrom boards Link here ( http://poorstudenthobbyist.blogspot.com/2014/10/making-your-own-nes-reproduction.html )

Wiring More specifically the part where it mentions 32pin eprom wiring for axrom boards about a 1/4 the way down:
128KB PRG ROM:
Bend up pins 1, 2, 24, 30, and 31. Connect pin 1 to hole 30, Connect pin 2 to hole 24, Connect pin 24 to pin 16, Leave pin 30 and pin 31 disconnected
256KB PRG ROM:
Bend up pins 1, 2, 24, 30, and 31. Connect pin 1 to hole 30, Connect pin 2 to hole 24, Connect pin 24 to pin 16, Connect pin 30 to hole 1, Leave pin 31 disconnected

Verified continuity to wires/pins/vias - I tried both of these wiring methods with no results.
Did I not wire it correctly, does it need wiring, or did I write the chip wrong. I left everything default when burning the chip and importing the bin file. Even did a blank check after I wrote it and it did indeed have data on it. Can provide pics if needed of my hack job of wiring or anything else. Someone point me in the right direction? :shock:

I'm trying to burn "Jeopardy! (USA) (Rev A)".


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PostPosted: Fri Jun 23, 2017 10:29 am 
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Location: Seattle
Some AxROM games specifically require not having bus conflicts. Unfortunately, which is which is underdocumented.

Games originally shipped on AMROM boards explicitly do have bus conflicts; games originally shipped on ANROM don't; games on AOROM might or might not.

If this is what's wrong—and Jeopardy! was originally shipped on ANROM—then you'll need to add an inverter to the cart to remove bus conflicts. There's a wide variety of parts that you could use—e.g. 74x00, 74x02, 74x04. Invert R/W—it's already present connected to the 74xx161—and connect the generated W/R to your PRG ROM's /OE pin.


I'm uncertain whether this thread should be moved to the Reproduction forum. We haven't exactly made it clear whether "Newbie help center" means "for everything but reproductions"...


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PostPosted: Fri Jun 23, 2017 11:18 am 
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First off sorry about posting in the potentially wrong area. I'm new around here and didn't see the Reproduction Forums. This post can be moved if required.
This being my first repro, probably not my greatest choice as a starter cart I can see lol. But I'll see if I can follow you here using the links your provided.

I have 2 options:
Either use 74x00, 74x02, or 74x04 part in place of the 74x161 chip
OR
Find the CPU R/W Pin (pin 14 on the US cart I think) and trace it to the 74x161 pin out, connect its traced pin to the /OE (pin 24) on my AM7C010?

&Keep the other wiring intact as well(128KB PRG ROM: Bend up pins 1, 2, 24, 30, and 31. Connect pin 1 to hole 30, Connect pin 2 to hole 24, Connect pin 24 to pin 16, Leave pin 30 and pin 31 disconnected)

At least this is how I interpret it. I'm not super savy with electronics persay, but I can be directed and execute accordingly.

Appreciate the help/reply btw.


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PostPosted: Fri Jun 23, 2017 11:35 am 
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Joined: Sun Apr 13, 2008 11:12 am
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Location: Seattle
silentadminz wrote:
Either use 74x00, 74x02, or 74x04 part in place of the 74x161 chip
OR
Find the CPU R/W Pin (pin 14 on the US cart I think) and trace it to the 74x161 pin out, connect its traced pin to the /OE (pin 24) on my AM7C010?
No, sorry I was unclear.

You need both the 74x161 and an inverter.

If you do decide to add an inverter, you need to take R/W (pin 9 on the 74x161), connect that to one of the inputs on the 74x00, 74x02, or 74x04 to generate a signal that is low when R/W is high, and connect the output of that inverter to your ROM's /OE pin.

Alternatively, you could temporarily give up on making a Jeopardy! copy and instead pick a game that originally shipped on AMROM—those don't need the ability to prevent bus conflicts.


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PostPosted: Fri Jun 23, 2017 12:18 pm 
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Quote:
No, sorry I was unclear.

You need both the 74x161 and an inverter.

If you do decide to add an inverter, you need to take R/W (pin 9 on the 74x161), connect that to one of the inputs on the 74x00, 74x02, or 74x04 to generate a signal that is low when R/W is high, and connect the output of that inverter to your ROM's /OE pin.

Alternatively, you could temporarily give up on making a Jeopardy! copy and instead pick a game that originally shipped on AMROM—those don't need the ability to prevent bus conflicts.


Ahh, I see. perhaps a bit out of my abilities at the moment. Although I'm sure I could manage it. It sounds like AMROM boards are also compatible from what you said. I'll look into that.
Jeopardy was just a test of course. I mean let's be honest who wants to play Jeopardy on the NES :lol:
Ultimately I wanted to turn it into Battletoads, but was waiting on the 2m Eproms I have on order.


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