Genesis 1 VGA Cable

[PowerBook86]

Hey guys I'm new here and I have a few questions concerning connecting the Genesis to a VGA monitor.

I have a Sega Genesis Model 1 and I would like to try and create a VGA cable for it to use with my VGA monitor. I have already soldered the 8 wires into the 8-pin DIN connector on the Genesis and I have the VGA female port ready but, I'm a little stuck. The Genesis has a 'Comp Video' wire, and the VGA pin-out labels, Luma (Y) and Chroma �. So I don't really know what to connect to where. I also have a 'Ground' wire coming from the Genesis that I'm not sure where to connect. I have only connected Red, Blue, Green, Sync, +5v, to the VGA connector so far, I did not connect any of the audio connections since I plan to use the Genesis's built-in stereo mini-jack on the front of the unit (and it will make things less complicated). So basically I need to know where the Ground, and Comp Video go to from the Genesis to the VGA connector.

Thanks a lot guys, I hope I'm doing this correctly. If not than that means I'll learn something.
Note: the below guest post is me, I wasn't logged in

[blackevilweredragon]

Firstly, you need to make sure your VGA monitor can even handle 15KHz scan rate, if it doesn't one of two things will happen, you'll get a blank screen and probably an error message from the monitor, or your monitor will kill itself as it can't handle it.

Second, composite video should not be connected, VGA don't need that.. If it's Composite Sync, then I forget which H+V it connects to (if even both), you'll also need to make sure your monitor knows how to get a composite sync (most monitors i've run across do it fine)...  VGA don't have Luminance, and Chrominance signals...

Ground connects to the D-Shell...

[Guest]

Firstly, you need to make sure your VGA monitor can even handle 15KHz scan rate, if it doesn't one of two things will happen, you'll get a blank screen and probably an error message from the monitor, or your monitor will kill itself as it can't handle it.

Second, composite video should not be connected, VGA don't need that.. If it's Composite Sync, then I forget which H+V it connects to (if even both), you'll also need to make sure your monitor knows how to get a composite sync (most monitors i've run across do it fine)...  VGA don't have Luminance, and Chrominance signals...

Ground connects to the D-Shell...

Awesome, thank you very much. The only thing I didn't have connected the D-shell was ground. I plugged it in without it and I got the black screen showing a question mark (because it could not find a signal). The monitor is Smasung 19" CRT SyncMaster 997DF, I was looking in the PDF manual for it (link here - Page 43) that it's Horizontal kHz can be from 30 - 90, and that it's Vertical Hz can be from 50 - 160. So I guess I'm out of luck, or I'm looking at the wrong thing here. So I would assume older or newer VGA monitors can handle 15kHz or maybe just not my model?

Thanks for your quick reply.

[blackevilweredragon]

Firstly, you need to make sure your VGA monitor can even handle 15KHz scan rate, if it doesn't one of two things will happen, you'll get a blank screen and probably an error message from the monitor, or your monitor will kill itself as it can't handle it.

Second, composite video should not be connected, VGA don't need that.. If it's Composite Sync, then I forget which H+V it connects to (if even both), you'll also need to make sure your monitor knows how to get a composite sync (most monitors i've run across do it fine)...  VGA don't have Luminance, and Chrominance signals...

Ground connects to the D-Shell...

Awesome, thank you very much. The only thing I didn't have connected the D-shell was ground. I plugged it in without it and I got the black screen showing a question mark (because it could not find a signal). The monitor is Smasung 19" CRT SyncMaster 997DF, I was looking in the PDF manual for it (link here - Page 43) that it's Horizontal kHz can be from 30 - 90, and that it's Vertical Hz can be from 50 - 160. So I guess I'm out of luck, or I'm looking at the wrong thing here. So I would assume older or newer VGA monitors can handle 15kHz or maybe just not my model?

Thanks for your quick reply.

Scan rate is the horizontal, which your monitors shows you CANT do...

Older NEC MultiSync's can take the signal, more modern monitors can NOT do it (some LCDs can though, mine can, and it's a AvidAV=cheap brand)..

[PowerBook86]

I just checked my older Apple MutliScan 1705 monitor (1995) and that won't even do it. Oh well, I should of looked into this more before starting but, thanks for all the information. The Genesis still works and maybe one of my old monitors in the basement will work with it. But, I don't think the VGA port on my Dad's HDTV will work with it...nor will I want to risk it Thanks again

[blackevilweredragon]

I just checked my older Apple MutliScan 1705 monitor (1995) and that won't even do it. Oh well, I should of looked into this more before starting but, thanks for all the information. The Genesis still works and maybe one of my old monitors in the basement will work with it. But, I don't think the VGA port on my Dad's HDTV will work with it...nor will I want to risk it Thanks again

Woah, wait a second here, HDTVs have "scalers", and they do have a chance for taking that signal..  It will just treat it as 480i though, not 240p, so it won't look perfect, but it MAY work...

Best bet:  Contact the manufacturer first though!

[blackevilweredragon]

I do have this CRT that works on the Genesis, but I was lucky mine worked with it, as others of the same model do NOT work with it..   It's an IBM 8512, not even rated for 15KHz, but this one was modded in it's life for 15KHz (it's magnets that make it scan inside, were heavily modified, probably by a professional)...

http://www.spymac.com/upload/gallery/2006/...egamonitor7.jpg
http://www.spymac.com/upload/gallery/2006/...3009_9lives.jpg

[viletim!]

PowerBook86,

Boring facts time!

Generaly speaking, VGA monitors don't work with 15khz video. There are some exceptions but they are extremely rare (and, in most cases, extremely old). If you want to play you Genesis on a VGA monitor you need a device called an Upscaler to make the video signal VGA compattible. If you just want to play in glorious RGB video then you'll need a 15KHz RGB monitor or a TV with an RGB input of some variety.

If you're building your own cable then you should be aware than the Genesis needs some electronic components placed in series (in between the source and the destination) with it's RGB video lines. It requires a 75 ohm resistor and a 220uF capacitor for each colour. You connect the ground of your Genesis to one (better, many) of the VGA cable's ground pins. You shouldn't connect +5 volts to any pin on a VGA input.

[blackevilweredragon]

PowerBook86,

Boring facts time!

Generaly speaking, VGA monitors don't work with 15khz video. There are some exceptions but they are extremely rare (and, in most cases, extremely old). If you want to play you Genesis on a VGA monitor you need a device called an Upscaler to make the video signal VGA compattible. If you just want to play in glorious RGB video then you'll need a 15KHz RGB monitor or a TV with an RGB input of some variety.

If you're building your own cable then you should be aware than the Genesis needs some electronic components placed in series (in between the source and the destination) with it's RGB video lines. It requires a 75 ohm resistor and a 220uF capacitor for each colour. You connect the ground of your Genesis to one (better, many) of the VGA cable's ground pins. You shouldn't connect +5 volts to any pin on a VGA input.

I needed caps and a resistor?    On my pics above, that monitor was connected straight to the Genesis..

[viletim!]

For correct operation on all TVs/monitors you need the capacitors and resistors. The sky won't fall in if you don't use them but you will get a better picture if you do.

[PowerBook86]

Well thanks for all the information! Now I couldn't buy a 8-Pin Din connector, nor did I want to split open my Genesis 32X cable, so I soldered my cables directly to the Genesis board. Unfortunately in this case a Multimeter will NOT tell you which pins are connected to which since they all are connected at one point or another. But, by studying some connectors and diagrams online I came up with my own little diagram, I used the information here for the port information but, I made this little image to help any of you who may need it. I did my best to label everything correctly although since I can not test my cable I can't be sure 100% that it will work but, here it is anyway.  

[NFG]

It's worth noting that in the original post a link is made to a VGA pinout with Y/C pins.  That's not a VGA connector, that's my custom video connector.  That's kind of a crucial distinction.

[PowerBook86]

Thanks for pointing that out, I noticed that after I started soldering, but luckily I found a proper VGA connector pin out online so no harm done.