Forums

Sega Master System / Mark III / Game Gear
SG-1000 / SC-3000 / SF-7000 / OMV
Home - Forums - Games - Scans - Maps - Cheats - Credits
Music - Videos - Development - Hacks - Translations - Homebrew

View topic - GameGear-TV

Reply to topic Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next
Author Message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Thu Sep 08, 2005 2:45 pm
Another bump. :-)

I figured I'd check on this after another month. I was kind of surprised nobody posted anything new since. Any luck with the final plans, Chris (finding that resistance value, and/or any other corrections)?

Hopefully, this project wasn't forgotten, and no one got burnt out working on it...I know I did years ago, but you folks made WAY more progress than I did with Victor Kemp. It would be awesome if the world were to finally see some completed plans for this (1 and 2 asic versions).

Or perhaps someone could clarify...was the 2 Asic version schematic complete and the 1 asic was having some issues? Or did both need a little smoothing out? I got the impression both needed some minor corrections, but please correct me if I'm wrong.

Thanks so much, guys!

-Rob
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Thu Sep 08, 2005 7:13 pm
If it's useful, the wiki could be used for documentation and different people can contribute their knowledge to the guide. Those with more enthusiasm can flesh it out and the experts can submit corrections, etc. See here for where to get started.
  View user's profile Send private message Visit poster's website
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Thu Sep 08, 2005 8:00 pm
Wiki...what a great idea, Maxim! I never would have thought of it. I can think of a bunch of applications for Wiki for similar projects, now that you mention it. Thanks!

-Rob
  View user's profile Send private message
  • Joined: 26 Dec 2004
  • Posts: 365
  • Location: Japan
Reply with quote
Post Posted: Fri Sep 09, 2005 1:57 am
There is no decoder yet for the 1 ASIC version. I don't know if xavier is working on it or not.

I didn't get burnt out; my GGTV is working great. As for the version I wired together, it's the same as the schematic that Sankichi put on his page. For the resistance I put on the R/B splitter, I connected a 75 Ohm resistor in series with a 100 Ohm pot to adjust the resistance with more detail. It works great now.
  View user's profile Send private message Visit poster's website
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Fri Sep 09, 2005 1:51 pm
Oh, ok, Chris...you decided to keep the pot. Sweet...I thought you mighta been trying to find an exact value using a non-variable resistor.

Taking a second look at the diagram (I believe this is the one you mean), where would those two components go?

http://img131.exs.cx/my.php?loc=img131&image=ggtv25nm.jpg
EDIT: (Actually, that's Xavier's doc, I believe)

Of course, there's also his other diagram here (EDIT: Sankichi's):

http://www.sankichi.flnet.org/image/ggtv-circuit-rev01.gif

I noticed on your site, Chris, that your design actually ended up only using that one pot, rather than Sankichi's 4 (5, if yours is included, I believe). What did you use in place of them? Also, it looks like you used 2x 74HC132 ICs...was that just to reduce clutter (just use two gates on each chip)?

http://www.disgruntleddesigner.com/chrisc/segahacking/ggrgb.html

Sankichi, If you are still following this thread, would you be willing to submit a revised diagram as if you made the device on a single board instead of two (to make it a little easier to read for a novice, especially if he or she chose not to build it into the battery cases)? Xavier, I remember you mentioned earlier you wanted to submit a diagram that was slightly easier to understand for a novice...is this something you would still like to do? :-) Seeing both Sankichi's and Xavier's diagrams really helps to get a better understanding of how to build this, being so different in approach...but since they are so different, I'm still trying to get a firm grip on it in my head (seeing where, if any differences lie).

EDIT: I'm noticing a few things I didn't pick up on before...For all 3 of the 74HCT574 ICs, do all three of them use Q0: 2.2kOhm, Q1: 1.1kOhm, Q2: 550 or 560Ohm, Q3: 270 or 275 Ohm? It wasn't really clear, from what I was seeing. Also on the last two, what is really the difference?

-Rob
  View user's profile Send private message
  • Joined: 26 Dec 2004
  • Posts: 365
  • Location: Japan
Reply with quote
Post Posted: Sat Sep 10, 2005 1:48 am
Rob, Sankichi's and Xavier's diagrams are very similar. The main difference is the order of the Valid lines and R,G,B control lines, since Xavier's order didn't produce correct results on Sankichi's or my GG.

I used the two IC to reduce clutter. I didn't put any pots on the RGB outputs (just a 300 Ohm resistor on each) since the output levels for all of them were balanced well.
  View user's profile Send private message Visit poster's website
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Mon Sep 12, 2005 2:27 pm
Thanks, Chris!

I guess the last two things I was wondering about is exactly where those two added components you mentioned go. Also, did you replace the 1kOhm VR with anything?

Thanks again! And as always, sorry if I sound way too newb...I've been learning much as I go. Logic gates made my head spin in college, and I guess they still do now, heh heh.

-Rob
  View user's profile Send private message
  • Joined: 26 Dec 2004
  • Posts: 365
  • Location: Japan
Reply with quote
Post Posted: Mon Sep 12, 2005 3:25 pm
Yes, I replaced the big blue 1K variable resistor with the two that I mentioned earlier. That should answer both your questions.
  View user's profile Send private message Visit poster's website
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Mon Sep 12, 2005 7:50 pm
Oh, pfft, lol! Gotcha...makes perfect sense now. Thanks Chris! You rock!

-Rob
  View user's profile Send private message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Wed Sep 14, 2005 9:44 pm
Hi Folks,

In searching for these components for this, I am finding that 550 Ohm resistors are basically impossible to find (or maybe I'm looking in the wrong places). Looks like 560 is quite common, though, and I wasn't sure if the circuit was too sesitive to change the resistance that much. I'd rather avoid using a 220 and 330 in series to save space, but I guess I could if it came down to it. :-)

Anybody have any good leads for these? I was having trouble finding the 100 Ohm VR Chris mentioned also.

My first sources I used here in USA were MCM Electroncs, then (ugh) Radio Shack, and then a whole lot of places online using Google.

Thanks again, everybody.

Yours,
Rob

EDIT: Found a great source for...well, everything. :-)

www.Mouser.com

They have a massive catalog of just about anything...super-friendly phone service too. They really do go way out of their way to find items for people. I'm surprised I hadn't heard of these guys before, since plenty of other similar companies have been sending me their catalogs since I was a kid.

They had 549 Ohm 1% resistors. I figured, close enough, even though 560s probably would be just fine.
  View user's profile Send private message
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Fri Sep 16, 2005 11:35 pm
Hello friends, long time to see you all :)

Sorry I'm actually overbusy on a BIG pc-engine project.

The design for the 2 Asics version can be considered as stable if not definitive, you can safelly use Sankichi diagram wich is far more easy to understand than mine.
If i found some time i'll try to post something more readable.

Quote
, I am finding that 550 Ohm resistors are basically impossible to find (or maybe I'm looking in the wrong places).


To be honnest I don't like the rounded value I personnaly use

2,2 Kohm 1% 1/4W
1.1 Koohm 1% 1/4W
2 x 1,1 Kohm 1% 1/4W PUT in PARALLELL so we obtain exactly 550ohm
4x1.1 Kohm 1% 1/4W PUT in parallel in order to obtain 275 ohm

it take more space but this way you are sure color are perfectly balanced.

Quote
There is no decoder yet for the 1 ASIC version. I don't know if xavier is working on it or not.


I actually found an SMS (at last) but I don't found an 1 Asic GG so for now further experiments are on hold.
  View user's profile Send private message
  • Joined: 28 Sep 1999
  • Posts: 1138
Reply with quote
Post Posted: Sat Sep 17, 2005 7:25 am
xavier wrote
Sorry I'm actually overbusy on a BIG pc-engine project.


At the risk of being off-topic, can you share any details? :)
  View user's profile Send private message Visit poster's website
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Sat Sep 17, 2005 1:27 pm
Take a look here:

http://www.zeograd.com/creation_download.php?lang=en&page=8

Just an animation test, not a fonctional engine yet.

Basically a port of the Sonic 1 SMS/GG version with lot of technical improvement.
  View user's profile Send private message
Plloi
  • Guest
Reply with quote
Post Posted: Thu Oct 06, 2005 6:28 pm
I noticed someone asked about using the GameGear like a mini TV, but it was mentioned that the circut would be too difficult or large to bother with. However, Just out of curiosity If someone were to work on it would it connect on the same locations as the GGTV?
 
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Thu Oct 06, 2005 7:11 pm
Good question, we can theorically re-input multiplexed RGB digital signal by the same connection than output ones ( Of course isolation must be made to avoid sending electric courant into the existing GG video processor output).
However sync output (T2) seem to exit only for the TV output and is not connected to the LCD.

The lack of good documentation about the LCD part is a problem too, maybe there is a simpler way to handle video input by directly work with this part.
  View user's profile Send private message
Plloi
  • Guest
Reply with quote
Post Posted: Thu Oct 06, 2005 7:43 pm
So perhaps breaking the original circut and placing a diode between graphics processor output and the new input to prevent signals from going the wrong way?
 
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Fri Oct 07, 2005 6:29 pm
Err, it's a very primitive way to handle this, but since we deal with digital signals ( 0V or 5V) I suppose it can work pretty well (quick and germanium type diode is better for this).

Another interresting information should be how the tuner actually send video information via the cartdridge connector.
But such information are pretty obscure if not unknow.
  View user's profile Send private message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Tue Oct 11, 2005 9:24 pm
Hi folks,

I've bought all the components needed to make my GGTV, but I'm having a terrible time finding a 2 ASIC model. Seems they are a lot less common that the 1 ASIC. Would anyone happen to have a 2ASIC they might sell me? Or even pointing me to someone who has one for sale would be great. As always, thanks!!

-Rob
  View user's profile Send private message
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Thu Oct 13, 2005 8:58 pm
I'm having difficulties, too. 6 GG's, 5 of those 1ASIC versions and one dead 2ASIC. :/
I have the circuit built and all, just need somewhere to stick it into.

First dibs to Rob of course but anyone has a stack of them, let me know.
  View user's profile Send private message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Tue Oct 18, 2005 7:50 pm
There is some debate in another forum whether the 2 ASIC models have no BIOS or whether they just have an earlier version of the BIOS. Chris mentioned earlier in the thread that they have no BIOS, so I was convinced by his word, but now others are saying otherwise. So, for curiosity's sake, which is it?

-Rob
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Tue Oct 18, 2005 8:45 pm
The GG BIOS is responsible for showing this screen:



If the GG doesn't show that, it's a "no BIOS"... as far as I know, there's no reason to believe there is a non-displaying BIOS.
  View user's profile Send private message Visit poster's website
  • Joined: 06 Jun 2005
  • Posts: 47
  • Location: United States
Reply with quote
Post Posted: Tue Oct 18, 2005 10:33 pm
on different games the bios screen seems to look different, Ive seen it at larger font, and things like that, is there a reason behind that?
  View user's profile Send private message Visit poster's website
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Tue Oct 18, 2005 11:22 pm
Last edited by Maxim on Wed Oct 26, 2005 7:12 pm; edited 1 time in total
When you boot an SMS mode game, the same screen is used, but it loads a different palette (so it looks right with the SMS mode palette). In that case, the font looks smaller, if you imagine this squashed to around the same size as the previous picture:


[edit: typo fixed]
  View user's profile Send private message Visit poster's website
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Sat Oct 22, 2005 12:58 pm
I'm sure too that 2 asic GG don't have BIOS.

Problem is maybe some early 1 Asic GG don't have BIOS too...

Question: Is the bios is built into the 1 asic chip or is in a separete rom chip?
If so maybe 1asic GG can work without BIOS by jumping directly to the cartridge code....
  View user's profile Send private message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Mon Oct 24, 2005 10:13 pm
Hmmmm, so I guess no one knows for absolutely sure there's no bios...It would difficult, but I wonder if it could be dumped. Wasn't there finally some GG schematics out now that some guy made (with chip pinouts, I assume)? I was working on some years ago, but I only got about 2/3 done and gave up, heh heh.

-Rob
  View user's profile Send private message
  • Joined: 21 Jan 2005
  • Posts: 77
Reply with quote
Post Posted: Wed Oct 26, 2005 5:09 pm
So what exactly is the BIOS in the later GGs actually used for, since games don't require the bios on older GGs?

Someone in another forum (the DP forum) said:


Quote
It's impossible for a Game Gear to not have a BIOS. The splashscreen was added to a later version of the BIOS, but the Game Gears without the screen definitely have a BIOS.

But let's say you are right. That would mean that there are 2 kinds of Game Gears. With and without BIOS. Old games (made in the time there was no BIOS) would run on both. 1) Newer games (made in the time GGs had a BIOS) would only run on the newer models (since the old models do not have the BIOS they require) or 2) they would work on both models but not use the BIOS at all. I've never heard of games that only work on a specific model of GG so assumption 1) is not valid. 2) is not valid either since why would Sega add a BIOS and not use it?


I remember hearing the bios really didn't do much at all, but only served a very minimal purpose...can't remember what that was though.

-Rob
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Wed Oct 26, 2005 7:10 pm
The issue here is that it isn't really a BIOS in the traditional sense - it doesn't contain code that the game can execute to perform certain functions. It's basically the same as the Mega Drive BIOS - it just shows that screen, and does a few checks on the cartridge to detect if there's one plugged in. Nobody's really sure why Sega added that in to both the GG and MD, it may have been a legal issue to make it easier to go after unlicenced software makers.

I believe the first Sega console with a "proper" BIOS was the Mega CD. All GG, SMS and MD games are fully self-contained with all the code needed to do everything required.
  View user's profile Send private message Visit poster's website
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Sat Nov 05, 2005 6:43 pm
I'm having a bit of problems with my work. The picture I'm getting is like this:

Dynamite Headdy title screen
Dynamite Headdy in-game 1
Dynamite Headdy in-game 2

Any ideas? The cable to TV is 2-3 meters and unshielded but it couldn't mess it up that bad, could it? Maybe signal levels aren't right and the TV goes haywire?
  View user's profile Send private message
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Sat Nov 05, 2005 8:45 pm
By order of probability:

1- Are you sure the ground is correctly connected
2- With a voltmeter verify presence of 5V on every CI power pin.
3- verify the fast blackink tension, scart pin 16 (must be around 1V).

If all is normal try to post some close picture of your circuit and its gamegear connection.
  View user's profile Send private message
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Tue Nov 08, 2005 9:20 am
Thanks for the suggestions. This week I'm terribly busy with other, boring things but I'll let you know how it goes next week.

Just gotta ask, the D0 in this picture should be on the other end of the resistor, right?
http://www.sankichi.flnet.org/image/gg-asic2-board.jpg
  View user's profile Send private message
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Tue Nov 08, 2005 12:50 pm
You are right, there is a small error on this picture.
The correct connection is as show in Chris site.

In other hand if Sankishi use this connection and obtain correct video output maybe it's not so grave...

But IMHO use Chris picture just to be sure ;)
  View user's profile Send private message
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Sat Nov 19, 2005 12:13 am
Finally got some time to check out my circuit. First of all I noticed the caps I used on the signal lines were not 1nF but 1microF. :/ After I sorted that one out, I had pretty nice picture but with no red. I tried to find the problem for about an hour or so but those SMD chips proved to be such a pain in the ass. Threw them out the window, bought some regular chips and started all over.

I decided not to use a PCB and stacked the 74HCT574s to save space. I used Sankichi's schematic but I left out the caps and the pots on the signal lines and used 220Ohm resistors instead as I didn't notice any real difference in the picture.

Well, what do you know, I now have a beatiful and sharp image! The only flaws I've noticed are some horizontal interference lines visible on large uniform surfaces and red seems brownish. I'm guessing the interference is caused by the SCART cable and how I just threw it together to test the damn thing but I'm more baffled by the brownish red. Any suggestions on what to look for?

Anyways, I put some photos here if you're interested. Sorry, they're about 1MB/piece. The picture really is sharp despite the photo, I just couldn't get it properly focused. I managed to fit the whole circuitry inside the GG and I'll try to hack the link cable connector later so it would still look like a regular Game Gear on the outside. :)

Thanks to all you guys for your help, you're awesome. :)
  View user's profile Send private message
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Sun Nov 20, 2005 8:51 pm
Congratulation!
Very nice result.

Quote
horizontal interference lines

Do you connect the pulldown resistors ( the 1Kohm ones)?

Quote
red seems brownish.

If you see some problem with Red try to adjust the Red/Blue separation resistor (the one connected to the NAND gate).

Fixed value for the output signal can depend of your TV set, but you are right, a 220ohm value seem to give good result on most of the case.

The 1nf capacitor output signal is REALLY optionnal, some TV seem to degrade picture if they are present, on other TV set the image look sharper with the capacitors.

Try and see what work the best.

Quote
I managed to fit the whole circuitry inside the GG and I'll try to hack the link cable connector later so it would still look like a regular Game Gear on the outside. :)


Well if you are sure you'll never need the link connector, it's a good idea!
However I don't know if the link cable is shielded?
  View user's profile Send private message
rbudrick.
  • Guest
Reply with quote
Post Posted: Thu Dec 01, 2005 3:18 pm
Davidleeroth,

What is that line you have connected to C26?

-Rob
 
rbudrick.
  • Guest
Reply with quote
Post Posted: Mon Dec 05, 2005 5:58 pm
Spoke to DLR and he said it was a preliminary ground.

So I finally assembled this cicuit this week and ran into a prety bad situation. Something is wrong with the circuit and I think it fried my GG. :-(

When I turn it on, nothing comes on the screen. In SMS mode, I can hear music, but no picture. Anyone know what is wrong (what to repair)? Did I completely destroy my GG?

Also, I live in the USA and I used an SCART cable that also happens to have Svideo and RCA cables coming off of it. Well, the SCART connector obviously can't connect to my American TV, but I tried the other connections before the GG fried and got basically what I would get from what Victor Kemp and I did years ago...only much worse. I have no idea what I did wrong on the circuit...

I'm not certain the RCA and Svideo ports on this cable work correctly with this circuit, so does anyone know of a good SCART to svideo/composite adapter?

Also, is is normal for the sound on the GG to go off when I connect my GG to the mod board? I basically added a 15 pin VGA port to the GG and made the mod board external. The mod board also has a 15 pin VGA prot on it to connect to the GG.

One final question for this post: does it matter if the capacitors are the polarized type? Many aren't and I used the type that aren't if that matters.

-Rob
 
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Tue Dec 06, 2005 9:02 am
This mod is for RGB, and I think S-video is hacked on to SCART by reusing the connections - it seems composite and red are used for luminance and chrominance. Since the circuit's making RGB, that should have just given a signal that your TV couldn't display. Did the GG work when the VGA port was connected, before connecting anything to it?

To mix RGB into S-video you'll need some external converter, which seems to be why a lot of people in the US look for RGB monitors instead.
  View user's profile Send private message Visit poster's website
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Tue Dec 06, 2005 10:25 am
Until more precisions from rbudrick, I just say US TV DON'T HAVE RGB INPUT.
As Maxim say even with SCART connector, the pin are assigned to other function.

In other hand, you can bought RGB->NTSC converter in good video shop or if you want a less expansive solution, you can built it from scratch with a good old Sony CXA1145P an RGB->PAL/NTSC converter chip (it need some external componant however)

Quote
One final question for this post: does it matter if the capacitors are the polarized type? Many aren't and I used the type that aren't if that matters.

No, it's not vital.

Quote
Also, is is normal for the sound on the GG to go off when I connect my GG to the mod board?

No it's not normal, there is a problem, short circuit or inversed 74xxx chip?
  View user's profile Send private message
rbudrick.
  • Guest
Reply with quote
Post Posted: Tue Dec 06, 2005 7:08 pm
Thanks, Xavier and Maxim.

I know my us tv doesn't have RGB, but I figured there might be a converter out there to go from scart to composite or svideo.

The VGA port was just a convenient 15 pin connector to go from the GG's added wires to the mod board itself. It wasn't serving as a true VGS plug or anything like that. However, even if it did, VGA monitors won't accept an ntsc signal, so I never thought to even try it like that. My setup is more like this:

GG with internal wiring added->cable(vga)->mod board->scart cable

Hopefully a scart to svideo/composite adapter can be added to this.

Quote
In other hand, you can bought RGB->NTSC converter in good video shop or if you want a less expansive solution, you can built it from scratch with a good old Sony CXA1145P an RGB->PAL/NTSC converter chip (it need some external componant however)


Is ther one anyone can reccomend? I did see the pdf for the Sony chip everywhere online, but no mod plans for it (what components to add, etc.) Davidleeroth pm'd me that gamesx.com probably has the plans somewhere, but I can't find it.

Also, some say that these converters, if they do exist would appear black and whit on my TV due to PAL limitations...my argument is that it may not, since the GG and my TV is ntsc. Any opinions on this?

Also, anyone have a guess as to how to fix my GG or what might be fried?

Also, can I ground my audio to common ground?

Thanks again, everyone!

-Rob
 
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Tue Dec 06, 2005 10:27 pm
Here's the gamesx page for the CXA1645, only a couple of extra components needed:

http://www.gamesx.com/rgbadd/genesis3.htm

Have you tried removing the circuit and running the GG after the initial test?


Anyways, I finally got my circuit working. The cause for the brownish red was the sync line which needed a 1.5kΩ resistor instead of the 270Ω to work on my television. The sync was good up until about 3.3kΩ in which point it became too weak.
Also, I forgot to mention earlier but I found the RGB lines to be mixed in Sanchiki's schematic. The correct pin configuration (for me at least) was R-11, G-8 and B-9+10 on the 74HC132 chip.

I hacked the link cable (which was shielded) and used the link port for output. It looks quite nice if I may say so. :) Too bad I dropped the GG not long after finishing the mod and the screen died. :( Everything else works still fine, though. I'll get a couple of photos up when I have the chance.

One last question: Does it matter if the GG is permanently wired for SMS mode? I mean, does it have any ill effects in games that were designed to use the GG color palette? Thanks.
  View user's profile Send private message
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Tue Dec 06, 2005 11:19 pm
Quote
One last question: Does it matter if the GG is permanently wired for SMS mode? I mean, does it have any ill effects in games that were designed to use the GG color palette? Thanks.


Quote
For SMS compatibility you must tie together T10 with T11 but i'll affect the LCD display so use a switch, not a simple wire.


After more test I can confirm there is some display problem when you let T10/T11 always connected, mainly in GG mode.

Quote
I forgot to mention earlier but I found the RGB lines to be mixed in Sanchiki's schematic. The correct pin configuration (for me at least) was R-11, G-8 and B-9+10 on the 74HC132 chip.


Argh..... Once again this inverted valid signal story rise from the tomb to haunt me ;)

Quote
The cause for the brownish red was the sync line which needed a 1.5kΩ resistor instead of the 270Ω to work on my television.


Strange, with 1,5Kohm the sync signal should be far too weak???
What TV set do you use?

Quote
Also, can I ground my audio to common ground?


If you speak of audio ground, then yes, you can connect it to your GG general ground.

Quote
Also, some say that these converters, if they do exist would appear black and whit on my TV due to PAL limitations...my argument is that it may not, since the GG and my TV is ntsc. Any opinions on this?


Such converter are avaible for both pal and ntsc output.

Quote
Also, anyone have a guess as to how to fix my GG or what might be fried?


As alway disconnect your TV-Gear and check your GG connection, if the GG don't start, you can have a short circuit on one of the solder point, or worse.
  View user's profile Send private message
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Wed Dec 07, 2005 1:46 pm
Thanks xavier, I have this TV:

http://www.computeruniverse.net/products/e90058949/Sony_KV_14LT1E_silver_Mono.as...

Like I said, the sync was good with values rangeing from 1.5kΩ to 3.3kΩ. Strange indeed. Never before have I had a problem with the sync level and I've had all kinds of stuff connected to it.
  View user's profile Send private message
rbudrick.
  • Guest
Reply with quote
Post Posted: Wed Dec 07, 2005 5:22 pm
Quote
After more test I can confirm there is some display problem when you let T10/T11 always connected, mainly in GG mode.


Hmmm, maybe a switch should be attached?


I found this scart to RCA adapter. Dunno if it will work, but it's the only one I've found online. All other seem to have male connectors.

Of course, if it doesn't work, I'll have to try the Sony mod. Are these chips still sold, or do they definitely have to be salvaged, as mentioned? Which system would be cheapest to salvage it from if so? Other than the connections shown in the mod, which are only the outputs, would I have to add these same additional components to all the inputs of the Sony chip too (r, g, b, sync, blank, vcc, ground)?

http://www.planetomni.com/CABLE_SCART_scart2rca-f.shtml

I did indeed disconnect the circuit and the screen is still fried. I wish I knew what component was gone so I could replace it.
 
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11761
  • Location: London
Reply with quote
Post Posted: Wed Dec 07, 2005 6:04 pm
A simple wired adaptor won't work, it will need to have a box in-line holding the chippery.
  View user's profile Send private message Visit poster's website
rbudrick.
  • Guest
Reply with quote
Post Posted: Wed Dec 07, 2005 10:13 pm
Quote
A simple wired adaptor won't work, it will need to have a box in-line holding the chippery


Right, I know. :-) Hopefully, this kind of circuit is built into the head of the scart cable. There's usually plenty of room in those plugs for additional electronics. Crossing my fingers that it will.

I would have thought this kind of adapter would be very common...apparently, it is not.

-Rob
 
rbudrick.
  • Guest
Reply with quote
Post Posted: Thu Dec 08, 2005 9:28 pm
Ok, here's some devices that seem to do what I'm looking for. Any opinions?

http://www.js-technology.com/index.php?cPath=22&osCsid=97e7ba25902f51f62deab...

http://www.maplin.co.uk/Module.aspx?ModuleNo=30782&TabID=1&C=SEO&U=S...

http://www.syncblaster.com/RGB2S.html
OR
http://www.keene.co.uk/cgi-bin/bigcodesearch.pl?RGB2S

Whew! That was some of the craziest googling I've done in a while...

-Rob
 
  • Joined: 04 Mar 2005
  • Posts: 9
Reply with quote
Post Posted: Thu Dec 08, 2005 10:17 pm
They all look good to me. But just because I'm cheap and poor, I'll still recommend hacking a dead PlayStation or Saturn for the CXA1645 chip. ;)
  View user's profile Send private message
  • Joined: 28 Sep 1999
  • Posts: 1138
Reply with quote
Post Posted: Fri Dec 09, 2005 3:02 am
rbudrick. wrote
Ok, here's some devices that seem to do what I'm looking for. Any opinions?


There's also this:

http://www.jrok.com/hardware/RGB.html

Based on the same Sony chip found in most videogame consoles, so I'd say it's probably quite reliable. Last I heard they go for $79 USD.
  View user's profile Send private message Visit poster's website
rbudrick.
  • Guest
Reply with quote
Post Posted: Fri Dec 09, 2005 9:16 pm
Quote
They all look good to me. But just because I'm cheap and poor, I'll still recommend hacking a dead PlayStation or Saturn for the CXA1645 chip. ;)


I suppose for the non-Euro folks here, it wouldn't be a bad idea to make a new diagram with the Sony chip...it would be cool to put it all on one board, plus we can adjust for that little Sankichi error and add the sync, blank, and T10-11 leads like on Xavier's) all on one doc.

Ummm, any volunteers? :-D :-D

The wiki thing is still a really good idea, imo. If I were already done this project, I might start it, but I'm afraid I'll make too many errors in description.

Xavier, any clues on the T10-11 poblem? Is a simple swith the best solution, or do you think there might be a permanent fix?

-Rob
 
  • Joined: 31 Dec 2004
  • Posts: 76
  • Location: France
Reply with quote
Post Posted: Sat Dec 10, 2005 11:05 pm
There is indeed a permanent solution, at least for me ;)

I used 2 unused pin in my DB connector, connect T10 on one and T11 on other.
In the external plug I shorted the equivalent ones.

So when I don't use TV-Gear, T10/T11 are open, and when I connect the plug, T10/T11 are shorted (T10/T11 shorted in GG mode when you use tv output is not a problem, it only jam the lcd display).

A simple, if not primitive method, but it work perfectly and don't require aditionnal componant.
  View user's profile Send private message
  • Joined: 21 Dec 2005
  • Posts: 6
Reply with quote
Post Posted: Wed Dec 21, 2005 11:14 am
Anyone have the list of all components for connect Game Gear to TV, please?

Thanks :P
  View user's profile Send private message
Reply to topic Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next



Back to the top of this page

Back to SMS Power!