Nintendo Super System Mod (Video Warm-up)

DogP

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Hey,

I just picked up a Nintendo Super System, and it has a problem where when first turned on, it comes up with a gray screen, and then it eventually (after 10-30 mins) fades into the normal screen. It's definitely the PCB and not the monitor. I'm very surprised that I can't find any info on this as it seems to be a REALLY common problem.

[backstory]
I first saw it this summer when I was helping w/ the CGE arcade machines. It worked when I tested it at the warehouse, but when we got it to the show, I thought that machine was broken. While I was trying to troubleshoot it, someone walked by and said that it was normal, and his machine does it as well. He said to just leave it, and eventually it'd start working (I though "yeah... sure" :p). So, I left it, and about 30 mins later I walked by and it was up and running.
[/backstory]

So, my new one does this, though just slightly different (this becomes visible within a minute or so, but stays washed out for quite a while, and occasionally snaps in and out).

Now... looking at the MAME source, I see info about a fix for various video and sound problems. But, I can't find ANY info about this mod except from MAME. I would have expected someone to have posted this somewhere, which would have caused the MAME guys to add it in... but it seems like either the MAME guys figured out the mod and just put it in the source, or the place that they got it from is long gone.

Nintendo Super System modifications

This describes main board modifications which corrects some
various video and sound problems on the NSS-1 version main PCB.

on the solder side of the main PCB:
-------------------------------------------------------------------------------------
Remove R101, R71, L55, L56
-------------------------------------------------------------------------------------
Solder jumper across L55 and L56 (shorting L55 and L56 independently)
Approx a 5" jumper wire from R101 (solder pad closest to C181- where
the below resistor will be) to the leg closest to R68
-------------------------------------------------------------------------------------
insert a 10 Ohm, 3 watt resistor on parts side of PCB between
C9 and C10
-------------------------------------------------------------------------------------

Volume control: 10KOhms

Sweeper --- pin 25
Ground ---- pin 26
Signal ------ pin c (opposite of pin 25)
-------------------------------------------------------------------------------------

CN2 pins 8 & 9 to pin 24
CN2 pins 4 & 5 to pin "b" (opposite of pin 24)

Does anyone know about this mod? Is it meant to fix the gray screen problem, or something else, or is it a hack that's gonna fry the system? :p Or does anyone else even have the gray screen problem?

Thanks,
DogP
 
Oh... since there were no replies, I forgot all about this. I'd personally recommend NOT trying the modification... first of all, the instructions aren't very clear, so I wasn't really sure what they wanted. I tried one way, which didn't help... then the other way which caused it not to work :p . I've never had any sound problems, so I'm not sure which sound problems it's supposed to fix.

I've figured out the problem though. The problem is with the voltage going to the IR3P32A chip. I couldn't find a datasheet for that chip specifically, but I found a similar chip, which had a voltage range of 8V-12V, nominal 9V. Rather than regulating its own voltage, Nintendo decided to just put a 100 ohm resistor between the Vcc pin and 12V, which brings the voltage down, but doesn't regulate it at all (the more current the chip draws = less voltage to the chip). So, the 100 ohm resistor was probably good when the chip was new and drew less current... but now that the chip is old, it draws more current, and eventually warms up (causing it to draw less current), which makes the video show up.

The voltage at mine was 7.5V... I added a resistor in parallel to bring the voltage up to about 9.5V and the video came right up looking great. I don't think anything else is affected by bumping that voltage up, but I should probably check to verify.

DogP
 
MIne has the same problem too, but it comes up after an hour, LOL!

I am looking for the most important thing though, the 0.2 Upgrade Chip. WTF do you get one of those?
 
The 0.2 BIOS is dumped and available in the MAME set... IIRC it's just a 27C256 (I burned one for mine, but didn't really notice any difference, except the menu changed when there's only one cart in the slot).

BTW, was that you that mentioned that I just needed to wait for it to come up this year at CGE?

DogP
 
Just build a regulated power converter and see if it fixes the issue.

If it does, then you'll be the hero. ;)

Use a 7809 regulator, a couple of small caps, and a small heat sink.

If you use an encased tab regulator such as Mouser part # 511-L7809CP then you don't even have to worry about the heatsink being connected directly to the ground tab of the regulator.

A 1 x 2" piece of perf board and a couple of bits of hardware to mount it and wire to connect it then you're done.

If you need a bit more than 9v then put a diode in between the ground leg of the regulator and ground. Try a schottky first then a regular diode to get a .4 to .7 bump in voltage.

RJ
 
Meh... I know it'd fix the problem, but there's the hassle of mounting it somewhere, and looking like a hack (even though it's really an upgrade). There's actually two through holes in parallel with the 100 ohm resistor... it's easy to just stick a resistor or pot through those holes to get it to the right voltage, though I did consider whether I could just add a 7809 through these holes (there's already large caps on both rails right there). The resistor is surface mount on the bottom of the board, so it's not as convenient to make changes to that (and probably not a good idea for soldering noobs to mess with).

DogP
 
The 0.2 BIOS is dumped and available in the MAME set... IIRC it's just a 27C256 (I burned one for mine, but didn't really notice any difference, except the menu changed when there's only one cart in the slot).

BTW, was that you that mentioned that I just needed to wait for it to come up this year at CGE?

DogP

I could have swore we looked there and could not locate one...but if you said there is a difference...then it HAS to be there

and yes, that was me that told you at CGE you just needed to wait for it to come up...
 
My board originally had an 01... I upgraded to 02, and I'm almost positive that with 01 it'd still show the selection screen with just 1 game... in 02, it just shows the only game installed. I haven't noticed any other differences, but they may be there. The 02 BIOS file in MAME is nss-ic14.02 .

BTW, thanks for the heads up on the gray screen at CGE... it was getting pretty aggravating since it worked perfectly in Tim's shed ;) .

DogP
 
Hey everyone-

I found this thread while researching my Super System today. It turns out the motherboard I have came premodded with the exact mod posted in the mame pcb info. I can confirm my super system turns on instantly with zero warmup time.

The only thing not done on my pcb mentioned in those notes is the X and Y to Select
Jumpers. I can't for the life of me figure out what they're for. If I had to guess it's so X and Y act as button 3 so it's jamma spec? Do any games use more than three buttons? I'd give this mod a go if it weren't foe the fact it may potentially fry the I/O circuit.
 
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