PDA

View Full Version : PAL Neo-Geo Cart System Problem



Vinevessel
08-25-2000, 06:26 PM
Hello Jeff,

Probably you know me, I am the one that plan to send my system to you couple weeks ago, but then still thinking better to save couple hundred US Dollars and buy a new, modified system from Shawn (Which has a modification installed from you of course) for around US$485.

Well, but if you don't mind, I just want to ask you couple questions regarding my 'broken' system and hopefully, it can be fixed http://www.neo-geo.com/ubb/smile.gif

As in my old E-Mail, you said that we can use SEGA Genesis Adaptor for Neo-Geo System, so what sort of Voltage and Current we need? (If I am not wrong, it's 9V 850mA).

Is the current rating really important? Because I saw in the original AC Adaptor is 1.2 A.

I tried to make a modification by myself by cutting the Resistor Jumper that was connected to PAL1 Jumper Area. Is it all for modification that need to force the signal to NTSC?

Well, I just follow it from Chris Mullins FAQ though several months ago, and he said just cut the resistor and that's it.

I don't know whether the failure caused by cuttign those resistor or not, because my AC Adaptor is also a bit broken, and can't transmit a 9V steady voltage sometimes going up and down, I knew it from the Multimeter.

Before I cut the resistor, the system already faced a difficulty in starting the game. I have to re-enter the Cart and Switching several times the On/Off before playing the games. Otherwise, sometimes I just can see scramble in the screen, like mozaic, or sometimes just dark screen.

After? Well, it's even worse on my system, it's totally gone (Is Chris really give a bad information???). I can't play any of my games, but I knew that the system is on 'cause the LED is on,.but I just can see scramble screen, just like what you usually faced with old NES,. you need to blow into your cart first before actually start the games.

But, of course I didn't blow my cart,.but I can't really play the games anymore.

Anyway, Thanks A LOT Jeff for all your help,.You are the best Tech.Support for Neo I reckon, 'cause I couldn't find any in Australia 'til now.

Have A Great DAY!

SmokeYa
08-25-2000, 07:53 PM
Hi,

I am not an expert on modifying neogeo systems, but I am an electrical engineer =) So here is a little advice...

The current rating is important, because if the AC adaptor can not supply the needed current, then the system will not operate properly (damage is possible also). If you attempt to draw more current from the AC adapter then it is designed to supply, it may cause the voltage level to drop. This is sometimes refered to as "loading down" the power supply.

If the NeoGeo system needs 1.2A and you are only using a 850mA supply, this may cause problems.

Note: Just because the supply is 1.2A, doesn't always mean that the Neogeo system really draws 1.2A. It may draw a lesser amount. So it is theorectically possible that you can get away with using a 850mA supply, but it is unlikely because 350mA is a pretty significant difference for a power supply of that size.

JMKurtz
08-28-2000, 08:40 AM
In order to convert a PAL system to NTSC, you need to do a couple things:

1. Remove that PAL resistor you were talking about.

2. Replace the video sync crystal with one that is rated at 3.579545 MHz - this is located in the top left area of the board.

3. Change the PAL/NTSC setting of the CXA1145 video decoder chip. Usually (on all the newer style boards), you will see an NTSC jumper that is empty and a PAL jumper that is set. Just take the PAL one off and set the NTSC one.

As for a power supply. I believe the old genesis power supplies are 9V 1.2A - I would have to double check.

Jeff

Mentor
08-29-2000, 09:06 AM
Vinevessel. Feel honoured, as I joined this BBS just to help you out ;-) Australian's should always help each other out =)

Anyway your power supply would either run at 10v and 1A (as is indicated on the official power supply that came with the pal neo geo) or 10v and 1.2A. I'm no expert, though I'm yet to find a pal neo geo that opperates at the power frequencys of Jap and US systems. Hence for a satisfactory power supply one could use a master system or megadrive (NOT genesis) power supply, easily obtainable from any cash converters store ect...

Jeff : Now about what you list here concerning switching the system to ntsc. Just somethings I have found myself..

Step 1 is cool. If you do this, you end up with what is apparrently a 60hz signal that broadcasts in the pal colour format. This result is actually quite satisfactory for any pal users with a multi frequency TV set.

Step 2 & 3: If you switch the crystal (done this in a couple of neo geo's just to test it) to an ntsc frequency crystal you actually get a detoriation in the picture quality (from RF and composite, no s-video for me. Only rgb). The jumper you speak off is set on ntsc and not pal in everyone of the few neo geo's I've opened.
*This is speculation, as yet I haven't actually attempted this, haven't got around to it*
It seems to me that the one also needs to replace the capasitors ect, that affect the occilation levels (I believe thats the right terminolgy) of the signal before in reaches the video ports.

There's my 2 cents.
Thankz
Mentor...

JMKurtz
08-29-2000, 09:52 AM
The newest boards, NEO-AES6, are this way. I'd have to check the others, but on the ones that I've changed, the jumper was always on PAL if it was a PAL machine. I've never checked beyond that (the caps, etc), but those should be safe. Something worth looking into down the line... This is not a common mod, so I haven't spent much time on it. But just cutting the resistor isn't enough in most cases (as a FAQ would have you believe).

Jeff

Mentor
08-29-2000, 10:11 AM
Quite frankly the caps are the only things I can think off to be honest =) I can't actually come up with an alternative reason.
When I've tapped the signal dirrectly from the cxa chip for composite video without going through the caps it doesn't suffer from the distortion, though naturally the colour spectrum is a little bright shall we say ;-)

Anyway cutting the pal 1 IS enough IMHO, if you have a pal TV set capabable of 60hz frequency. Everyone who I've had contact with in pal countries (that I've discussed this with) has only used this meathod and everyone has had success. I can't speak for the NTSC market though, this is beyond my experience..

Thankz
Mentor...

JMKurtz
08-29-2000, 12:44 PM
That's just it... Everyone over here is NTSC based. Most TV sets over here don't support 50Hz. We're just now getting SVideo on cheaper sets, and Component Video on some mid-range sets. This still isn't true RGB, but I guess we work slow over here.

If we just remove the pal resistor for the 60Hz, the crystal is at the wrong clock and we end up with a B/W picture. So, replacing the crystal makes it work properly. Setting the jumper on the CXA chip just takes it a step further to insure the CXA is set properly.

As for trapping the composite signal, just add a 75Ohm resistor and you'll be set. This is the same thing I do for "Enhanced Composite" mods. This mod isn't really needed if you have the SVideo mod, but if you don't, it can greatly improve the Composite picture. This is a mod that anyone could do.

Jeff

Vinevessel
08-29-2000, 05:24 PM
Hi Everyone,

Thanks a lot for all. I do really appreciate it your help.

You too Mentor...thanks mate for your help! I do feel honoured so much though http://www.neo-geo.com/ubb/smile.gif

Well, as to be honest, I am still a bit confused with the problem I have and still not sure what factor that cause my Neo'S System not working.

Hi Mentor, do you willing to accept to repair mine? Well, because you do live in Australia and that's lot cheaper than sending my system to Jeff in the USA. But, this just if you don't mind to fix it though http://www.neo-geo.com/ubb/smile.gif

'Cause you seemed understand a lot with the technical of Neo Geo Cart System.

Anyway,..Nice to meet you Mentor,.at last I can get a buddy in Australia that is like Neo Geo..hehe.. http://www.neo-geo.com/ubb/smile.gif Btw..how you get your game from? It's hard isn't it to search a game here.

Thanks ALL!

Regards,

Ivan Adrianto.

Mentor
08-29-2000, 10:14 PM
Jeff -> Yep I understand that. Thats why I qualified my statement only concerning pal countries and since Vinevessel is in australia =) S-video is extremely rare here in australia and so is scart. Composite is all the go here generally =(

Yep. What you said about the crystal ties in with what I said about it being a 60hz pal signal. Frequency is right, but the colour system is wrong.

Thanks for that about the resistor, I'll try that and use a ntsc crystal again. That should hopefully enable a fully working ntsc system with pal NEO-AES6 pcb. (I've roughly checked a scan of an ntsc pcb against mine and except for the pal jumper the board jumper setting are indenticle)

Vinevessel --> Always happy to help. Anyway personally I think the Biggest reason your system isn't working is that it ain't getting enough power =) Try a megadrive (original model) power supply with it and get back to us =)

As for fixing your neo geo (doesn't wanna be cramming jeffs style here ^_~) I COULD Fit a new crystal, change jumpers, check that you haven't damaged the pal1 jumper (rip these out and it don't work :-/) and attach a nice av port to the back of the neo. What I won't do is supply a debug mod chip (if you buy off jeff I would install for you if you wish), do an s-video output. I suppose I could do a stero mod, but frankly Jeffs a great guy and I don't want to go stealing his buisiness. And no thats not a butt kiss ;-)

Incidentally I wouldn't say I understand alot about the technical side of the neo geo, just a reasonablely good knowledge of some of the basics.

As for finding carts my friend, it's a long, hard and difficult process. I've never found home carts in a store myself as I'm not located in one of the capital cities. The nets been useful, found a few peeps to trade with in oz that way. About the only store that sell home carts in oz that I can think of is gameinfinity in sydney, but I've never bought from them. I've tried to deal with them over the phone, but you can't seem to get any sense out of them. People I've spoken to have gotten some good deals in person from them though. Someone picking up a last blade 2 for instance at around $250 aussie if I remember correctly.. Actually I need a contact in sydney again to see what they got again..

Anyway feel free to email me if you wish.

Thankz
Mentor...

Vinevessel
08-30-2000, 04:09 AM
Dear Jeff Kurtz,

Thanks a lot Jeff for all your help. Well, to be honest and just to let you know, I won't and not intent to disturb your business as I am just a desperate Neo-Lover who looking for a Technical Support for 'minimal' cost as I am just a student and really have a 'tight' budget.

I do live in Melbourne, Australia and I am really thought over and over again to send my system to USA, and end up with at least will cost me around US$100-US$150 including 2 way shipping and fixing cost, which is close to get a 2nd hand good condition Neo-Geo Cart System from Super Seller in Japan.

Fortunately, Mentor came up and is really helpful to me http://www.neo-geo.com/ubb/smile.gif

Thanks a lot Jeff!

Dear Mentor,

You're really helpful mate, thanks! I don't really want to disturb any of Jeff's Business. I am asking you to fix my Neo-Geo Cart System as because I do live in Australia, not USA.

So, well this is just my opinion though, you won't disturb any of Jeff's Business as because you are servicing the Australia Area. Just tell me if I am wrong http://www.neo-geo.com/ubb/smile.gif I planned to send mine to Jeff last month, but then cancel it due to 'high' cost in 2 way shipping Aussie-USA : USA-Aussie.

Yap, I do agree that Jeff is really a professional technician and installer for any Neo-Geo Mods. I will instantly send my system to Jeff if I do live in the USA.

Well, so I think I decide to send my system to you to have it inspected and fixed. Yup, if can, I want to have it modified so that it can have an NTSC output and Stereo output. But the main thing is that, it is working http://www.neo-geo.com/ubb/smile.gif

If you think I need to use the Sega AC Adaptor, do you have one? Can I buy from you?

And,.well,.can you also give me your E-mail address by the way? So we can talk easily.

Anyway,.thanks a lot ALL and Have A Great Day!

Regards,

Ivan Adrianto.

JMKurtz
08-30-2000, 08:25 AM
Ivan,

Please, send your system to Mentor to save yourself the time and money. If he can do the mods, fix your system, or whatever, send it to him.

Mentor,

I'm constantly sending business to Adol for the Debug mod for people that inquire about the chip outside of America. I would gladly send people from your region to *you* when they inquire about a mod, that is, if you don't mind me sending them your way. I would have sent Ivan your way last month for assistance if I had known you would help.

I usually inform people of the costs involved with shipping systems around the globe and I tell them only to send the system if it is something they absolutely want. It would be nice to send people from other countries to someone local to them.

Jeff

Mentor
08-30-2000, 09:50 PM
Jeff--> Ok then, thanks. Feel free to point anybody in my dirrection, just mention that I don't do s-video or debug mods, thats all http://www.neo-geo.com/ubb/wink.gif

Ivan --> Your welcome for the help. A fellow aussie neo users is hard to find http://www.neo-geo.com/ubb/wink.gif Though there are a few in Melbourne. Here's my email addy anyway.

mentor@omninet.net.au