It is currently Sat Aug 19, 2017 8:01 am

All times are UTC - 7 hours



Forum rules


Related:



Post new topic Reply to topic  [ 11 posts ] 
Author Message
PostPosted: Fri Dec 30, 2016 3:28 pm 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
Hi.
I just got an Starfox cartridge, board only (SHVC-1C0N5S-01).
It's locking at the first screen, sometimes the word Nintendo appears completelly, sometimes part of it and sometimes I just get a black screen with the music.
I tried to remove the resistor? that is plugged in place of the HC04, through pins 1 and 2 and put a wire in there.
So far so good, the game worked, but freezes after some time.
AFAIK, this componnent feeds the clock signal to the Mario-1 chip.
Is it so critical that without it the game crashes or I have something else wrong?
Is it really a resistor or some kind of inductor? The measured resistense is about 1ohm.
Thanks in advance.


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 3:58 pm 
Offline

Joined: Mon Jul 02, 2012 7:46 am
Posts: 759
It's an inductor, not a resistor, and yes, it's necessary. Without it, I'm guessing you're getting a lot of noise on the clock, which could definitely crash the game.


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 4:02 pm 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
The pictures I saw show the inductor with small trimmed terminals.
Mine is almost touching the 256k SRAM.
Could this be the source of my problem, since I'm dealing with high frequency RF here?


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 4:11 pm 
Offline

Joined: Mon Jul 02, 2012 7:46 am
Posts: 759
Could be. Photos would help.


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 4:38 pm 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
I took 2 pics with my crappy phone, hope this helps to have an idea.
Attachment:
20161230_212628.jpg
20161230_212628.jpg [ 634.56 KiB | Viewed 1067 times ]

Attachment:
20161230_212645.jpg
20161230_212645.jpg [ 596.04 KiB | Viewed 1067 times ]

The capacitor on the left was missing.
If I have read the pictur I saw fine, it's a 22mf x 6,3v.
I don think it's critical, is it?
Can an external clock generator be used?


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 5:16 pm 
Offline

Joined: Mon Jul 02, 2012 7:46 am
Posts: 759
Almost looks like pad #2 from the U6 footprint is ripped off the substrate, but I don't know if that's even connected to anything. I'll have to take a look at my board once I'm home from vacation after the first.


Top
 Profile  
 
PostPosted: Fri Dec 30, 2016 5:25 pm 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
I tested with the multimeter and got continuity there.
Maybe My soldering iron was too hot when I put it back.
It seems to go to pin 69 of the Mario chip.

Edit: I figured out! It's a faulty inductor!
If I have undestand what I read, the original inductor is 0,1 or 0,2 microhenry (I just can't know if the second belt is brown or red), but I have put a 27 microhenry one.
Even far bigger, it seems to be working fine.

Thanks and happy new year!


Top
 Profile  
 
PostPosted: Wed Jan 04, 2017 11:28 pm 
Offline

Joined: Wed Nov 30, 2016 9:59 pm
Posts: 52
Fisher wrote:
I tested with the multimeter and got continuity there.
Maybe My soldering iron was too hot when I put it back.
It seems to go to pin 69 of the Mario chip.

Edit: I figured out! It's a faulty inductor!
If I have undestand what I read, the original inductor is 0,1 or 0,2 microhenry (I just can't know if the second belt is brown or red), but I have put a 27 microhenry one.
Even far bigger, it seems to be working fine.

Thanks and happy new year!


It's definitely red. Gold-Red-Gold on mine at least. That said I need to point out something, you said you have a bare PCB (no plastic cart case?) Well the StarFox game has a metal object in the cartridge that connects to that pad behind 59 and 60 on the PCB. This is an extra ground AFAIK that would normally make contact with the metal cartridge slot. Someone who was cleaning cartridges stated that the cartridge slot ground and the RF shielding in the SNES completes a ground circuit. YMMV.

_________________
I come from the net. Through systems, peoples and cities to this place.


Top
 Profile  
 
PostPosted: Fri Jan 06, 2017 5:47 pm 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
Interesting!
I didn't know that.
Is it all shielded, just like the N64 cartridges?
Could you please show some pictures?
So I can try to make something similar.
Thanks in advance.


Top
 Profile  
 
PostPosted: Fri Jan 06, 2017 11:32 pm 
Offline

Joined: Wed Nov 30, 2016 9:59 pm
Posts: 52
Attachment:
Mario-Chip1-SFX.jpg
Mario-Chip1-SFX.jpg [ 675.47 KiB | Viewed 805 times ]
I scaled this down from my iPhone and quickly drew an arrow to where it makes contact on the PCB

Incidentally the Super Mario RPG cart also has one in the same place. So it might exist on all expansion-chip carts. That could also explain why these carts are more finicky since there might be a weird ground loop. If someone creates a new cartridge plastic they might not realize this.


Attachments:
SMRPG-vs-STARFOX-Ground.jpg
SMRPG-vs-STARFOX-Ground.jpg [ 278.36 KiB | Viewed 802 times ]

_________________
I come from the net. Through systems, peoples and cities to this place.
Top
 Profile  
 
PostPosted: Sat Jan 07, 2017 5:03 am 
Offline
User avatar

Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
Thanks!
It's working fine now, but I think I should try to implement this shielding to avoid future problems.
It would be easier if I found someone selling a StarFox's shell only. :mrgreen:
I would buy it complete, if it wasn't costing a kidney!!

By the way, I just put a clockgen I found floating around... 28.570Mhz, a slight overclock!
Some people say the game becomes smoother, but I saw no difference besides a faster moving ship and the intro sound not playing to the end.
Maybe it's me, but I think it's better as it was designed to be.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 4 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