Sega SG-1000

Bryce · 15:31, 22 November 12

The Master System 2 offers Composite but not S-video as far as I know. Composite is only slightly better than a UHF signal. The colours are good, but it's rather unsharp. S-Video is the next best, because it has the colour and intensity signals separated - Good colour, relatively sharp picture. RGB is the next. This separates the 3 base colours and has a separate CSync signal. Component video is the next step up and probably the best picture you can get on a standard TV.
It's easy to convert RGB to Composite but only for convenience where you don't have RGB, otherwise it's pointless because the picture is being degraded. Converting RGB to S-Video is also quite easy, the picture quality of S-Video is very close to RGB, especially at the resolutions used by retro gear. I prefer to use S-Video just because the cable is very thin and I have S-Video inputs on my TVs. Converting to Component or anything higher (DVI / HDMI) is complicated and also rather pointless, because the signal resolution is much better than the video signal the system can actually produce. It's like putting a 1080p screen on an 80's digital watch

Bryce.

Gryzor · 19:47, 22 November 12

Your TV has s-video? Wow, talking about retro...

Bryce · 21:00, 22 November 12

Even the latest Panasonic Plasma TVs still have an S-Video input, that's why I stick with them

Bryce.

robcfg · 22:16, 22 November 12

I hear my Yeno SC-3000 crying for some love

I'll have to try and load some tape dumps, but getting a SF-7000 unit would be top notch!

Anybody knows where to get one?

beaker · 23:29, 22 November 12

Quote from: Bryce on 15:31, 22 November 12
The Master System 2 offers Composite but not S-video as far as I know.

From what I remember getting a s-video signal from the SMS2 wasn't too hard. I had a go at that one myself following a youtube video as the thing only cost me 1c off ebay plus some postage so it wasn't like I was going to lose too much. Here's a picture of my handy work as Gryzor moaned at me last time "Yeah, yeah, yeah, keep on bragging about how many of them you have and how wonderfully modded they are." so it only feels right to keep on banging on about it

[attach=2]

Quote from: robcfg on 22:16, 22 November 12
I'll have to try and load some tape dumps, but getting a SF-7000 unit would be top notch!
knows where to get one?

OK, what the heck is a SF-7000?!?!

ivarf · 23:35, 22 November 12

Quote from: Bryce on 21:45, 21 November 12
The power switch (bottom right) is a work of art.

Why do you say that?

robcfg · 23:53, 22 November 12

Quote from: beaker on 23:29, 22 November 12
OK, what the heck is a SF-7000?!?!

The SF-7000, Dear Sir, is this beauty: SC-3000 Survivors :: The ultimate SEGA SC-3000 reference site - The SEGA SF-7000

That gives the SC-3000 a huge boost!

beaker · 00:17, 23 November 12

That does look right tasty! I'd hate to think how much it would go for. I suppose you could always put a wanted post on Amibay?

Bryce · 13:39, 23 November 12

@Ivarf: I say that because it's a thing of beauty. Completely open custom made rocker switch. As you can see in the photo below. The bent metal on the left acts as a spring, the two contacts are on the right (and are filthy, I must clean those too while I'm at it).

@Beaker: I meant the Master System didn't have S-Video as standard. I'm sure there were mods to convert it. Nice job you've done there. Just for Gryzors sake, how many of these do you actually own and how are they modded? A short list would be nice

Bryce.

beaker · 15:16, 23 November 12

urm... just that one (and I think I lucked out not frying any of the chips to be honest). That one just has the 50/60hz switch, s-video and composite. Like the SG-1000 it only outputs mono so have bridged the left and right channels with the same signal. I actually hooked it up again last night after taking the photo and spent the evening playing Alex Kidd and then Psycho Fox (both of which I sucked at). Otherwise not sure where I gave Gryzor the idea I've made more unless I told an outright lie at some point...

Gryzor · 20:54, 27 November 12

Hahaha I really don't remember.

But, yeah, go on, brag about them you snob.

Bryce · 18:02, 15 December 12

Unfortunately I've encountered some issues with the SG-1000 mod: The point on the PCB, where the CSync signal should be, definitely doesn't have a sync signal. The second problem, which is probably a bigger issue, is that the SG-1000 isn't producing any sound. I've connected the device to an NTSC TV, that can definitely handle Japanese signals and I've even connected the scope to the point where at least mono sounds should be. There's nothing there. Unfortunately both issues would suggest that the Sega Custom chip isn't fully functioning. That would be unfortunate, because there's no chance of replacing this part.

I'll do more tests tomorrow and report back if I get any results.

Bryce.

beaker · 19:49, 15 December 12

Ah that's a shame

I only managed to get sound on it like twice otherwise most of the time is was a deathly silence. I don't suppose it shares any parts with the Sega Master System that came after it we can use as a donor if needs be? Otherwise I guess it's a paper weight...

Bryce · 20:14, 15 December 12

Was it real sound you got, or just noise? Sometimes it produces noise, but I haven't got anything close to recognisable sound yet. I very much doubt that they used the same chip in the Master.

Bryce.

beaker · 20:21, 15 December 12

No, it was proper sound the same as in the video link below for the pro wrestling - it almost made me yearn for the silence again mind

I think the soccer one almost did a passable whistle as well.

Edit: Hopefully with right link this time

Bryce · 20:40, 15 December 12

Ooo, in that case I need to keep looking, maybe something else has failed. I'll test all other parts tomorrow.

Bryce.

beaker · 21:48, 15 December 12

Cool, thanks Bryce. Fingers crossed it's something simple like a dodgy capacitor like what happens with the Sega Gamegear but I am not normally that lucky. I don't know if this helps but this is how I described the problem to the seller last month:

"I've managed to get an image but I am having problems getting sound. I've tried 3 TV's (Pioneer plasma, Goodmans CRT and Philips CRT) and managed to get sound on the Philips CRT momentarily until I go to store the channel."

I think I also managed to get sound on the Philips one by manual tuning once but then I changed channel and when I changed back it had gone.

Not sure if that indicates a really weak signal?

Thanks,

Beaker

Bryce · 15:52, 16 December 12

Yeaaa! Good old persistence, if it doesn't kill you, it may just get you what you wanted

After testing all components and finding them ok, I took a break (played some Chuckie Egg to cool the nerves) and went back to try again. After looking at some solder joints under the microscope I decided there might just be a few of them that aren't that good any more, so I resoldered almost the entire board (all ICs and capacitors). And look there, all of a sudden I have both sound and a CSync signal

So I finished the amplifier and soldered it all up. It's now working fine with SCART and Dual-mono sound. I still have to do the case modding and then fix the controllers, but the difficult bit has been solved

Bryce.

Here's some pictures to keep you entertained...

beaker · 21:02, 16 December 12

Awesome, thanks for persevering Bryce. You're a legend!

It looks great so far!

I am sort of picturing the moment it all started working playing out a little like this...

Bryce · 09:49, 17 December 12

Yes, it was a very similar scene... I really need to cut down on the LSD

Bryce.

Bryce · 15:19, 19 December 12

I did some tweaking on the RGB amplifier this morning (yes I'm already on my Christmas break!!) and I've improved the picture and colours slightly. Here's a few screenshots of what it looks like now.

Bryce.

P.s. I'm almost sorry I fixed the sound, boy does it have annoyingly crap effects.

Gryzor · 15:28, 19 December 12

The video and the comment about having fixed the sound are the highlights of this thread. But the photos look fantastic, I bet no SG user has seen such great image before!

Heart-warming story, I'm sure everyone will agree

T

PS Xmas break already? Wow. Some DC gaming, perhaps? *wink* *wink*

Bryce · 17:19, 19 December 12

Just finished modding the SG-1000 case. The sockets had to go on the top half due to the PCBs position and all the other connectors at the back, and even then there's not loads of space available because of the ridge in the case etc for a connector as big as the 8pin DIN. The plastic is thick, brittle and old and the DIN socket crosses the split of the case, so I didn't try to drill this 16mm hole with a big drill bit, I hand carved it, which explains why it's definitely nowhere near a perfect circle

However, the thick plastic allowed me to sink the stereo output socket and mount the DIN socket on the inside, so the end result is quite tidy.

Bryce.

Gryzor · 14:49, 20 December 12

Still looking very neat...

Bryce · 15:19, 20 December 12

I just fixed the two controllers and now I've started on a MultiCart for it. Due to lack of a 1MB EPROM or in other words, seeing as I have a 2MB EPROM, I've deviced to go for a 64 Way MultiCart

Whether beaker likes it or not

Bryce.

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Sega SG-1000