It is currently Wed Aug 16, 2017 4:41 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Fri May 12, 2017 2:00 am 
Offline

Joined: Fri May 12, 2017 1:29 am
Posts: 3
Hi all !

Im new to the forum, and new to the NES comunity. In fact, I came from the enemy of Mario :oops: . (SEGA MASTERRACE :twisted: ). Unfortualy my girlfriend hate Sonic and loves play to Mario 1 & 3.

In order to work properly for Mario 3 (US version on EU Nes), I managed to kill the CIC chip. Beacose of realy bad dessolder tools, I finaly totaly removed the 10NES and try to figure out why the NES couldn't start properly without this chip.

I finaly resolder with some wire the 10Nes with the LOCK/KEY pin 4 to ground and the NES work perfectly now.

BUT it make me fell bad to know that a chip is badly soldered on the NES and want to understand how to remove it entierely.

As I understood from my (badly screwed) modification I have some questions:

- The RESET button of the NES is ONLY linked to the 10 Nes RESET pin 7. It is LOW or HIGHT logic ? (Reset occure when LOW or when HIGHT ?) It is pulled hight/down ?
- The NES must have a Power On Reset. Where is it ? On the RESET button line a simply a Capacitor + Resistor + Shmitd Trigger ? Is it the 10NES managing this feature ?

- Simply : How we can simply remove the CIC chip ?

If the POR is managed in the aera of the RESET button, I should just link the RESET pin 7 to the /Host reset pin 9 whith inverter (If I correctly understood, RESET pin 7 is Active HIGHT, but /Host reset pin 9 is active LOW).
If the POR was managed by the CIC chip, I need to add a custom POR OR'ed whith the inverter put between pin 7 and pin 9.

This is correct ?


BTW : Realy sorry for my bad english.


Top
 Profile  
 
PostPosted: Fri May 12, 2017 3:48 am 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 470
Location: -29.794229 -55.795374
Welcome to NesDev community!!

I've found a page on my notes that states this:

- Remove the 10NES chip and the crystal X2;
- Bridge the 10NES pin 7 to X2's pin 3;
- Bridge the 10NES pin 9 to X2's pin 1;
- Remove one of the terminals of the R1 (1MOhm), and solder on C6's terminal.

Just like this:
Attachment:
Remove NES CIC.jpg
Remove NES CIC.jpg [ 26.34 KiB | Viewed 662 times ]


About the "fanboyish" stuff, I really regret I was one when I was a kid. :(
I've lost a BIG part of the fun! And the purpose of games is just it: to have fun!!
So, let's have fun!! :D


Top
 Profile  
 
PostPosted: Fri May 12, 2017 5:15 am 
Offline

Joined: Fri May 12, 2017 1:29 am
Posts: 3
Thanks a lot for the tip.

I'll try it ASAP, and post result when done.

Being a Sonic Fan never stop me to make some competition on Mario 1 as a kid with my friends. (I was terribly bad at mario, but I always get fun)

I growed up in a non-"fanboyish" environment, and i need to admit, Nitendo was more fun in multiplayer than Sega in a general way.

As you say, lets have fun !


Top
 Profile  
 
PostPosted: Fri May 12, 2017 10:28 am 
Online

Joined: Sun Apr 13, 2008 11:12 am
Posts: 6023
Location: Seattle
Huh, someone else came up with the same hack I did: viewtopic.php?p=98891#p98891


Top
 Profile  
 
PostPosted: Sat May 13, 2017 2:00 am 
Offline

Joined: Fri May 12, 2017 1:29 am
Posts: 3
Hi

It reassures me, I'm not the only one who screwed up his 10Nes CHIP.

As I see, the hack is using an inverter to connect the reset button to the CPU reset.

But in the other thread I see some capacitor added. Why ?

Is this for assure the Power On Reset ?


Thank again !


Top
 Profile  
 
PostPosted: Sat May 13, 2017 11:14 am 
Online

Joined: Sun Apr 13, 2008 11:12 am
Posts: 6023
Location: Seattle
Yeah. If you don't have some capacitance—the circuit that both Fisher and I shared reuses one of the ones on the board—when you first turn it on, 2A03 /RESET will be high too soon after 2A03 VDD, and the CPU will be in some invalid state as a result. You have to make sure that /RESET rises enough later in order for cold boot to work reliably.

Without some capacitor, the user needs to press the RESET button once after power is turned on in order for things to work.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: flaviocaste, krzysiobal, lidnariq, Memblers, MLX and 9 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group