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
Author Message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Sat Jan 29, 2011 12:09 pm
For some reason my account was deactivated so I had to make a new one. For the record, I am genuinely interested in talking about SMS and Game Gear and I'm not here to cause trouble! When I tried to log in, it told me to contact the forum administrator, and there was no way of doing that without logging in! If someone could explain why this happened it would be helpful.

Anyway, I have a question for viletim or anyone who knows -
With the PNP and NPN transistors, do they both have to have exactly the same maximum collector current, rated voltage, or power dissipation? I am having trouble finding the exact ones in the diagram, or ones that match each other. I can either use higher current ones (1Amp) or lower current (0.1Amp). I can only find 0.5Amp ones for the NPN type. I'm using RS Components in the UK.

Maxim - I did some research last night and I found out that 15.5kHz and 31.5kHz are fine for VGA input. Older true VGA monitors did use these. New high resolution monitors use 120kHz to display 1600x1200 UXGA for example. The new monitors should be backwards compatible. I am surprised how similar VGA is to SCART in RGB mode, just one extra signal is added.

To double the resolution I think we somehow have to speed up the carrier signal to double it's frequency, (called time-stretching) so that each pixel is displayed twice in a row. I'm not sure about the vertical synch yet. Since vertical synch is going to need to be at 60Hz, 75Hz or a normal refresh rate. We can experiment :) .

The 160 horizontal pixels will become 320. The 144 needs to be 288. This 320*288 is not a normal 4:3 resolution, it's normally 320*240. The Game Gear aspect ratio is actually 10:9. Almost square. To get 4:3 we have to increase the width to make 12:9 (equals 4:3), or decrease the height to get 10:7.5 (also equals 4:3). Personally, I think increasing the width is easier and better because we're not removing resolution, simply stretching the image 20%. Some TV's may have this feature already.
  View user's profile Send private message
  • Joined: 27 Apr 2005
  • Posts: 420
  • Location: Australia
Reply with quote
Post Posted: Sun Jan 30, 2011 3:09 am
jimmimak, was wondering if this (below) was one of the sites you came across. If not, there is a wealth of info regarding scaling hardware here http://retrogaming.hazard-city.de/
  View user's profile Send private message
  • Site Admin
  • Joined: 08 Jul 2001
  • Posts: 7692
  • Location: Paris, France
Reply with quote
Post Posted: Sun Jan 30, 2011 3:12 am
Hello Jimmymak, sorry for your account. We've been having huge problems with fake/spam accounts recently and perhaps deleted a few new accounts by mistake.
  View user's profile Send private message Visit poster's website
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Sun Jan 30, 2011 8:58 pm
@DMEnduro:
That link you sent is really good, thanks! It's just the kind of stuff I'm trying to find out about. I just had a quick skim over it, and it mentions 240p being a problem for some new LCD TV's, therefore external upscaling is probably required before the signal reaches the TV. I'll have to read it properly when I get the time.

One thing I've noticed is that PCs seem to be able to upscale images and video really easily, but I guess digital upscaling is not the same. I wonder since we have the digital video signals from the chip, whether it's possible to convert to DVI or HDMI... eliminating DAC errors and noise. Probably can't, but it's just a thought.

@Bock:
Maxim told me about it the other day, it seems quite a drastic measure, the spammers must have been quite bad!
  View user's profile Send private message
  • Joined: 24 Sep 2006
  • Posts: 191
  • Location: Sydney, Australia
Reply with quote
Post Posted: Mon Jan 31, 2011 2:03 pm
jimmimak wrote

Anyway, I have a question for viletim or anyone who knows -
With the PNP and NPN transistors, do they both have to have exactly the same maximum collector current, rated voltage, or power dissipation? I am having trouble finding the exact ones in the diagram, or ones that match each other. I can either use higher current ones (1Amp) or lower current (0.1Amp). I can only find 0.5Amp ones for the NPN type. I'm using RS Components in the UK.


BC548/558 are rateds for a maximum collector current of 100mA. They are also two of the most common transistors is Europe and I'm sure RS has millions of them. If you're really stuck you can use the American transistors 2N3906/3904.

jimmimak wrote
I am surprised how similar VGA is to SCART in RGB mode, just one extra signal is added.


All analog video signals from consumer electronics (in the west at least) are electricaly compatible - 0.7Vpp @ 75R - it's the timing which is the problem.

jimmimak wrote

To double the resolution I think we somehow have to speed up the carrier signal to double it's frequency, (called time-stretching) so that each pixel is displayed twice in a row. I'm not sure about the vertical synch yet. Since vertical synch is going to need to be at 60Hz, 75Hz or a normal refresh rate. We can experiment :) .


You might be interested in the Micomsoft XRGB 3 and other scalers which are designed for video games. It isn't worth the trouble to DIY unless you're extremely determined...
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Mon Jan 31, 2011 9:18 pm
@viletim:
Thanks for the info. I can get 100mA transistors easily, it's just the 500mA ones (that I thought you were using) are hard to find in RS.

Re the XRGB -
The link DMEnduro sent has got a review of the XRGB 3. A bit pricey though. I saw some cheaper ones on eBay for £30. Will they handle GG resolution?

I have seen a forum thread on DIY SCART to VGA box, which confirms how easy it is to do. They are using a dedicated chip, the EL1883 to produce the v synch, but it the whole thing only costs £5, and produces the same results as a £120 converter.

I found my computer monitor specs, and the Game Gear frequencies are out of range. My analogue input specs are below FYI:
Horizontal Freq. Analog : 30 - 83 kHz (Automatic)
Vertical Freq. 56 - 75 Hz (Automatic)
Input Form Separate TTL, Positive/Negative, SOG (Sync On Green)
Input Form RGB Analog (0.7 Vp-p/ 75 ohm)

I'll probably make the SCART version first, and then make the converter that thread talks about. This won't be for a long time, too much to do.
  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Tue Jun 28, 2011 9:20 pm
Hello has all I am mick, j have to realize the ggtv

My problem are that l image on my tv are green?
I do not arrive has poster of photos

I know not or looked the breakdown.

If some one can m helped

thank you
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Jun 29, 2011 8:28 am
MickGW wrote
Hello has all I am mick, j have to realize the ggtv

My problem are that l image on my tv are green?
I do not arrive has poster of photos

I know not or looked the breakdown.

If some one can m helped

thank you


This looks like this has been translated on Google or something, but I can just about understand it...

If you have a green image, it could mean some of the pixel lines aren't connected / synched properly. It could also mean your SCART pins are arranged differently for your region - I think Japanese and European SCART are different...

This thread contains a lot of problems like that which have been solved, so I recommend looking this thread to figure out your problem.

Good Luck!
  View user's profile Send private message
  • Joined: 24 Sep 2006
  • Posts: 191
  • Location: Sydney, Australia
Reply with quote
Post Posted: Wed Jun 29, 2011 2:35 pm
MickGW,

The circuit is complex an contains many parts. You must isolate which parts are not working correctly. If you have access to an oscilloscope it will be easy, if not you can rearrange the circuit and use the process of elimination.

The circuit contains a pixel clock generator with 3 * CLK outputs, 3 * DAC, 3 * video driver. Swap parts of the circuit around to determine what works. So far you know the green DAC and the green video driver is functional....
  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Tue Oct 18, 2011 6:29 pm
Then j saw again(revised) my cabling j found 2/3 errors but j always have no image clear(net).
I realized a cable of 3000mm are that the length n are not too long me and created by the parasites.

I would like to redo the project with an easy plan that her(it) but I find not e plan of cabling on the GG of Xavier
EAGLE Version 4.16r1 Copyright (c) 1988-2006 CadSoft

Or I could found that

Or found has purchase of the already made circuit realized ?

Thank you
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Feb 22, 2012 1:07 pm
Viletim, I found some stuff that may/may not be useful to your RGB output mods.

A resource on video conversion:
http://www.repairfaq.org/sam/vidconv.htm

Sync Separator IC with horizontal output:
http://www.intersil.com/products/deviceinfo.asp?pn=EL1883

TV to VGA conversion chip (scan doubler):
http://www.averlogic.com/AL250.asp

With the last chip, I think you could connect your RGB console to a VGA monitor. Probably more worthwhile for higher resolution consoles. Having said that, VGA CRT's have good stretch/zoom ability for enlarging GG games.

Alternatively, you can buy "CGA" and "EGA" monitors that sync at 15kHz, but it's not future-proof. They use a 9-pin connector like you find on a Sega control pad. AFAIK, they use the same RGB as the GGTV output, horizontal and vertical sync can be combined or separate but it needs both.

For people looking to replace the Game Gear screen, I found these, they take composite signals (not sure where to buy them):
http://www.jr-electronic.net/tftvideomod_e.html

The LCD must have a video ADC, so there's a slim chance it could take analog RGB also (or, use Viletim's board with composite out).
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Mon Feb 27, 2012 8:13 pm
Sorry to double post but...

Just in case anyone is interested, I managed to find some UM70C171 on eBay. This is the chip that Xavier talked about, he said he suspected SEGA had a clone of this chip in the real GGTV. It essentially should do the same thing as the TV Gear circuit, but in one IC.

http://www.ebay.com/itm/UM70C171-50-UMC-IC-28-Pin-DIP-NOS-70C171-/390076904170

I also found some clones by other manufacturers, but could not find suppliers.
National Semiconductor DAC0631
Hitachi HD153129
  View user's profile Send private message
  • Joined: 28 Sep 1999
  • Posts: 1138
Reply with quote
Post Posted: Tue Feb 28, 2012 2:56 am
Quote
This is the chip that Xavier talked about, he said he suspected SEGA had a clone of this chip in the real GGTV. It essentially should do the same thing as the TV Gear circuit, but in one IC.


This chip is a VGA RAMDAC type part, and sorry to say it can't be used in a GGTV modification.

I wonder if Xavier thought this chip was used at an earlier point in his research, as his later schematic shows he knew how the chip should function and would know the 70C171 wouldn't be appropriate.
  View user's profile Send private message Visit poster's website
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Fri Mar 02, 2012 3:13 pm
Quote

This chip is a VGA RAMDAC type part, and sorry to say it can't be used in a GGTV modification.

I wonder if Xavier thought this chip was used at an earlier point in his research, as his later schematic shows he knew how the chip should function and would know the 70C171 wouldn't be appropriate.


Hmm, he seemed so certain, and never said anything to the contrary afterwards. I see that the chip requires palette definitions in binary from a processor or something, maybe the GG has the palette lines somewhere? I have seen a site where some guy is making a home made computer (I think it was a Z80 spectrum) and he used one of those chips. The GG is also Z80 at least.

Is there a schematic for the Game Gear and pinouts for the ICs anywhere? Google is failing me.

Edit: Here is the home made computer with the chip-
http://www.hanssummers.com/newz80.html
  View user's profile Send private message
  • Joined: 28 Sep 1999
  • Posts: 1138
Reply with quote
Post Posted: Fri Mar 02, 2012 4:29 pm
Quote
I see that the chip requires palette definitions in binary from a processor or something, maybe the GG has the palette lines somewhere?


Nah, it really can't work. You'd have to patch every game with extra code to set up that chip appropriately.

The actual chip the GGTV device uses is a Sega custom part, 315-5294, which isn't really even a chip but is a hybrid module (small PCB with an IC and some passive components). There is no commercially available equivalent of it.

But we don't really need the chip at all, because Sega implemented it with discrete components in their earlier arcade games which we have schematics for, so we know how it works. The implementation that Xavier and Tim use in their GGTV circuit is essentially the exact same thing.

So IMO the GGTV problem has been solved completely and there isn't a need to find a replacement for that chip at this point. If somebody really wanted to go for originality, they could salvage the 315-5294 from an arcade board. But it won't make the output look any better or improve anything.

Quote
Is there a schematic for the Game Gear and pinouts for the ICs anywhere? Google is failing me.


Sadly there is not. I've been dying to get a 2-ASIC Game Gear so I could make pin assignments for the chips. Managed to buy several GGs that turned out to be 1 ASIC versions so far. :(
  View user's profile Send private message Visit poster's website
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Fri Mar 02, 2012 5:12 pm
@ Charles MacDonald

Interesting stuff, I hope you manage to reverse engineer the Game Gear so it can be reproduced. A non-emulated pocket Game Gear with modern parts, a better d-pad, 40-hr battery and tv-out would be awesome. It needs a re-release more than any other IMO. The emulator GGs are awful.

I only have 1-ASIC European versions, so I can't help you on the 2-ASIC. Why not find the pinouts with the 1-ASIC version? I guess you want a more complete picture of whats going on in there?
  View user's profile Send private message
  • Joined: 28 Sep 1999
  • Posts: 1138
Reply with quote
Post Posted: Fri Mar 02, 2012 6:00 pm
Quote
I only have 1-ASIC European versions, so I can't help you on the 2-ASIC. Why not find the pinouts with the 1-ASIC version? I guess you want a more complete picture of whats going on in there?


Yep, I'm really interested in seeing what kind of data is passed between the chips. Also they are physically larger and easier to attach probes to. The single ASIC has tiny pins that are just too small to work with (I tried :)
  View user's profile Send private message Visit poster's website
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Sat Mar 03, 2012 1:18 am
Quote
The single ASIC has tiny pins that are just too small to work with

I agree, but nothing is impossible. If you're willing and skilled enough, you can try de-soldering it using a heat gun and put it in a socket with bigger pins. If there's no socket available, you could possibly etch your own pcb that expands the pins out to some header pins. Not sure how you'd connect it up to the Game Gear at the same time though, maybe a similar thing again with a custom socket with wires going to the GG solder joints. Resolder using reflow oven/heat gun. I've also seen people place PCBs on a hot clothes iron to melt the solder and remove BGA parts.

Maybe this will give you some inspiration to do it (reverse engineering the PSP):
http://sec.pn.to/pw/?plugin=attach&pcmd=open&file=tapping.jpg&refer=...

Translated:
http://translate.google.com/translate?hl=en&sl=ja&tl=en&u=http%3A%2F...

Note the BGA chips he removed and hand soldered to wires, then soldered wires back to the motherboard! :)
  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Sun Mar 04, 2012 11:44 am
Hello somebody know a plan for realized a GGTV for step too dear (expensive) the plans would like used that we find on this forum those of KE6ALM know you if he are well

thank you
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11826
  • Location: London
Reply with quote
Post Posted: Sun Mar 04, 2012 11:58 am
MickGW wrote
Hello somebody know a plan for realized a GGTV for step too dear (expensive) the plans would like used that we find on this forum those of KE6ALM know you if he are well

thank you

Your translation is not understandable, sorry.
  View user's profile Send private message Visit poster's website
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Sun Mar 04, 2012 12:05 pm
OK :)

I look realized a ggtv what will be their best plan ?

That of the KE6ALIM is it good, but I find not plan of the cable and those for cabled the card on the GG?
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Sun Mar 04, 2012 1:24 pm
MickGW wrote
OK :)

I look realized a ggtv what will be their best plan ?

That of the KE6ALIM is it good, but I find not plan of the cable and those for cabled the card on the GG?


I have no idea what KE6ALIM means. All the guides can be found in this forum thread. Here is a list:

http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html
http://www.freewebs.com/vgmods/gamegearmodifications.htm
http://www.geocities.jp/rajiaki_uchiaki/ROST/rost_gg_rgb.html
http://www.sankichi.flnet.org/ggtv-rev01.html

Take note that the SCART cable pins are different in PAL and NTSC regions, so you have to wire them depending on your region. If you don't have SCART, you need a composite or S-Video encoder.
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Mar 14, 2012 1:02 am
OK, I spent this week making a GGTV, and tested it today. Unfortunately it doesn't work, so I wondered if anyone might recognise the problem here. On my smaller TV I can see a fine red and a blue line on screen that move around, but it's just a black screen on the large TV. I can hear the sound OK.

At first, my big TV went into widescreen, as it needs 12 volts, so I now use a separate 12v supply, and it seems to be in RGB mode. I assume my TV works at 60Hz.

I have a feeling I held the soldering iron on one of the flip flops too long while trying to get a wire to stay still, so once I try all other options I'm gonna try replacing that (not easy as all the wires have to be reattached correctly).

I can't feel any heat from any of the ICs, which I would expect especially if I fried one of them. The lack of heat makes me think there is no power going to the board. I'm taking power from the place where most people wire the LED mod to (where the fluorescent tube transformer used to be).

Some of the data wires are up to 10cm, and I know they are meant to be kept short, I don't think this would cause a blank screen though..?

I'll keep at it, but if this problem sounds familiar to anyone, please help if you can. Thanks!

Edit: Checked the power on the board and it's fine. The flip flops are showing very low voltage outputs and inputs though - less than 1 volt on most. This is using a multimeter, so it is probably averaging the reading.
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Mar 14, 2012 3:07 pm
I made some progress on the GGTV today. I found that the composite video (Csync) wasn't coming out of the right SCART pin, and fixed it. Unfortunately, the colours aren't right...

It only works on my smaller TV for some reason.

More images here:
www.mejuba.com/albums/JMak87/93123

Notice how Castle of Illusion is greyscale... :-/

EDIT - I switched the colours around like this
TV board -> Scart pin:
Red -> Blue
Green -> Red
Blue -> Green
Now the correct colours appear but they are dark/dull, and when the screen fades e.g. on Sonic 2, the correct colours appear momentarily during the fade sequence. I tried adding potentiometers after the 75ohm resistors, but it makes it worse. I think the 75 Ohm are mean't to go to ground not in series like on Viletim's schematic, any ideas? My guess is during the fade seq. the 1k resistor stops flow to ground as voltage decreases, and more signal goes through to the TV, improving the image.

  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Wed Mar 14, 2012 4:38 pm
tu a utilisé quel méthode.
moi,aussi je suis sur un projet mais l image n est pas net et j arrive pas a trouvé la panne.

je posterais des photos.
  View user's profile Send private message
  • Joined: 31 Oct 2007
  • Posts: 808
  • Location: Estonia, Rapla city
Reply with quote
Post Posted: Wed Mar 14, 2012 4:59 pm
COI is greyscale because of being an SMS game in disquise and color info is sent in a different manner in SMS mode.
  View user's profile Send private message Visit poster's website
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Mar 14, 2012 5:13 pm
@ Mick
I used Viletim's guide here:
http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html
With some differences - I used 74HC374 instead of 74HC574, and I didn't stack the ICs.

@TmEE
I recall there is a pin that I need to connect on the cartridge connector to force SMS mode, will this make it work? Is there a picture online that shows which pins to connect?

I just used my multimeter on the 1k resistors between the 548 transistors and ground, and when my tv board is connected to everything, I get about 100 ohms, and when disconnected from everything it is 1k... :-S I thought I needed to add trim pots somewhere to correct the output levels but now I am confused.
  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Wed Mar 14, 2012 5:39 pm
I used the same plan as you j reproduced has l identical
  View user's profile Send private message
  • Joined: 29 Jan 2011
  • Posts: 19
  • Location: UK
Reply with quote
Post Posted: Wed Mar 14, 2012 10:40 pm
I have just made a video to show my colour problems and how the colours appear correct for a short period when the screen is fading. It is as if the colours are too intense for the TV so they are looping around to the first values again, but during the fade sequence they go low enough to appear normal.

http://www.youtube.com/watch?v=3_flOSdI7lw

I tried bypassing the inverter in case my IC's didn't need H-sync inverting (could have caused inverted colour values), but that results in a blank screen. Maybe theres too much gain on the transistors or not enough resistance or something...?

Edit:
I just inverted the order of the data pins D0-D3, and now the colours are almost perfect! I think my resistor ladders may be upside down(?). Using the 74HC374 instead of 574 caused some confusion. Also, when I touch the data lines, some of the noise disappears, and the picture improves; this could mean I need to shorten the wires. I added some small ~100Ω trimmer potentiometers in series after the 75Ω and it helps balance the colours.
  View user's profile Send private message
  • Joined: 28 Jun 2011
  • Posts: 7
Reply with quote
Post Posted: Thu Apr 19, 2012 7:42 am
I too put 74HC374 has the place of 574.
My breakdown can come of her ?
  View user's profile Send private message
  • Joined: 08 Aug 2012
  • Posts: 2
  • Location: UK
Reply with quote
Post Posted: Thu Aug 23, 2012 12:16 am
anybody willing to supply me with a ggtv board?, i can fit it myself just dont have the skillz to make one!
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 11826
  • Location: London
Reply with quote
Post Posted: Thu Aug 23, 2012 7:09 am
http://www.smspower.org/forums/viewtopic.php?t=11931
  View user's profile Send private message Visit poster's website
  • Joined: 08 Aug 2012
  • Posts: 2
  • Location: UK
Reply with quote
Post Posted: Sat Aug 25, 2012 1:20 am
Thanks!, PM'd viletim, hopefully get a positive response!
  View user's profile Send private message
Reply to topic Goto page Previous  1, 2, 3, 4, 5, 6, 7



Back to the top of this page

Back to SMS Power!