GUIDE: Telling apart good Genesis 1s and Genesis 2s from bad ones.

[Ace]

Looking for a good Sega Genesis/MegaDrive or just want to know if you've got a good Genesis console? Here's a list of almost all Genesis models and their variants. As always, any extra information and information on hardware missing from the list is welcome. So, here's the rundown:

NORTH AMERICAN HARDWARE

Genesis Model 1

High Definition Graphics model:




Two different variants of the High Definition Graphics Genesis Model 1 exist, one which boots straight to the game, the other will show this screen before booting whatever game you've inserted:



If your Genesis Model 1 shows this screen, it has TMSS, which puts up this screen before playing whatever game you have inserted in your Genesis. If your High Definition Graphics Genesis Model 1 does not show this screen, it doesn't have TMSS.
To figure out if you have a non-TMSS High Definiton Graphics Genesis Model 1 or a TMSS High Definiton Graphics Model 1, it's as simple as flipping your console over and taking a look at the FCC ID.

This is the FCC ID of a non-TMSS High Definition Graphics Genesis Model 1:



And this is the FCC ID of a TMSS High Definition Graphics Genesis Model 1:



Any Genesis Model 1 with TMSS will have a shorter FCC ID. Some people are very picky about whether their Genesis has TMSS or not.

Keep this in mind when looking for a High Definition Graphics Genesis Model 1: there have been several reports of Genesis Model 1s with FJ846EUSASEGA as the FCC ID containing TMSS. There appears to be a certain production run of Genesis Model 1s with FJ846EUSASEGA as the FCC ID with a motherboard revision containing TMSS. Specifics on these revisions are not known yet.

Motherboard revisions:

-Non-TMSS: VA2, VA3, VA4, VA5
-TMSS: VA6

Video encoder:

-All motherboard revisions: Sony CXA1145

Composite video quality (RGB is the same on every console, which has the best quality possible no matter what video encoder is used as the video is not encoded):

(Little note: these consoles are used on a 27" Electrohome CRT TV from 2007 with maximum sharpness, 75% brightness, 50% color saturation and 50% contrast. Picture quality may vary depending on what TV you use and your TV's settings)

-VA2 to VA5: Clear picture with vivid colors, slightly blurry, but overall very nice. These systems do have what's known as "rainbow banding" where there are thick fixed vertical bars of rainbow colors on the screen, most noticeable on a plain white, plain gray or plain black screen. It varies from console to console, and it can easily be ignored. This is typically caused by capacitors that are drying up, so you may be able to completely eliminate rainbow banding by recapping the console. There is also a bit of fringing visible on certain things on the screen (this is when you see rainbow colors on the edges of certain graphics).
-VA6: Same as VA2 to VA5 systems, but without rainbow banding.

FM Synthesis hardware used:

-All motherboards: Discrete Yamaha YM2612

Sound circuitry/sound quality:

-All motherboards: Use two separate sound amps/mixers for Mono and Stereo sound. They provide some rather heavy filtering, resulting in sound output with a perfect balance of high bass and clean high-ends. Sounds phenomenal.

Non-High Definition Graphics model:




Pretty much as the name describes: a Genesis Model 1 with "High Definition Graphics" removed. Like with the High Definition Graphics model, two variants of the Non-High Definition Graphics model exist, and you must be made aware of how to tell them apart, as one of them is quite a stinker.

In order to tell the good and bad non-High Definition Graphics Genesis Model 1s apart, you must first keep the placement of all the plugs in the back of the High Definition Graphics model in mind:




Now here's the back of one of the non-High Definition Graphics models:



This one has the hookups placed exactly like the High Definition Graphics model, but the hole where the EXT port is supposed to be is covered because the port and all circuitry associated with the EXT port is removed.

And here's the back of the other model:




This is the stinker. Read on to find out why this model is bad enough to be named a "stinker."

Motherboard revisions: VA6, VA6.8, VA7

Video encoder:

-VA6, VA7: Sony CXA1145
-VA6.8: Sony CXA1145 or Fujitsu MB3514

Composite video quality:

Sony CXA1145:

-All motherboards: Same as the VA6 motherboard in the High Definition Graphics model

Fujitsu MB3514:

*no information yet*

FM Synthesis hardware used:

-VA6, VA6.8: Discrete Yamaha YM2612
-VA7: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-VA6, VA6.8: Use the same two sound circuits for Stereo and Mono as the High Definition Graphics model, which means the sound is just as good.
-VA7: Sega changed the sound circuit for this motherboard, and let me tell you, it stinks. Bad. It sounds like an emulator's sound quality was set to the lowest possible setting; it's flat, muffled, distorted, and worst of all, there's an annoying hissing sound in the background (static). Unless you can send this console to TmEE so he can apply his Audio Mod to your console or you can build the Audio Mod by yourself, do yourself a favor and stay away from this model.

One think to make note of is that the YM3438 in the VA7 Genesis Model 1 has a slightly different sound to it than a discrete YM2612 and even a discrete YM3438 due to a better DAC as well as considerably less audible quantization noise. It's capable of MUCH better sound than what you would typically get out of a VA7 Genesis Model 1, but with Sega having screwed up the sound circuit as badly as they did, the sound output is much worse than it really is.

Small note concerning the hissing noise: the amount of hissing in the audio output is fixed out of the Mono audio output at the back of the console and will always be at its absolute maximum, but through the headphone jack, keeping the volume slider below 20% volume will greatly reduce the amount of hissing in the audio output. It still sounds like crap compared to your typical VA2 to VA6.8 Genesis Model 1, but it's much more tolerable.


Genesis Model 2



The casing is identical for all variants.

Full motherboard model:

In order to determine your Genesis 2's motherboard size, you need to turn over your console and take a look at the metal plate through the air vents:




This is a full motherboard Genesis 2; the metal plate is as wide as the console. There are many different motherboard revisions, each with their own variants.

Motherboard revisions: VA0, VA1, VA1.8, VA2, VA2.3

In order to tell the motherboard revisions apart, you need to hold your Genesis Model 2's cartridge slot open and take a look at the motherboard.

VA0:



VA1/VA1.8:



VA2:



VA2.3:



Video encoder:

-VA0, VA1, VA1.8: Sony CXA1145, Fujitsu MB3514 or Samsung KA2195D
-VA2, VA2.3: Samsung KA2195D or Sony CXA1645

For the most part, you will never know exactly what encoder is in your Genesis Model 2 until you open it up and have a look at the motherboard, but generally, if your Genesis Model 2 says MADE IN MALAYSIA on the bottom of the console, it should have a Fujitsu MB3514. VA2s and VA2.3s that say MADE IN CHINA should also typically have a Sony CXA1645. The others can have either of the 4 encoders, but you will never find a CXA1645 inside any Genesis Model 2 with a VA0, VA1 or VA1.8 motherboard.

Composite video quality:

Varies greatly depending on the console, the TV said console is used on and your TV's settings.

Sony CXA1145:

-Generally identical to VA6 and VA7 Genesis Model 1s, but may sometimes be darker and have more heavily saturated colors (this was experienced by Kool kitty 89 on his VA0 Genesis Model 2)

Samsung KA2195D:

-Personal tests on my TV yielded generally very poor picture quality with all but one Genesis Model 2 with the Samsung KA2195D as its video encoder. On the TV I personally use, the graphics are generally heavily pixellated and sometimes have dull colors. Some consoles, on the other hand, can have not so bad video off the KA2195D. It's still pixellated, yes, but not as bad. The real problem with the KA2195D is that it adds in thin vertical bars of a darker shade than whatever's on the screen, which makes the picture look really nasty. Again, this will vary from console to console and from TV to TV, but if there's one thing that's guaranteed, you will get vertical lines on your TV screen. This encoder generally produces picture with no fringing, but might sometimes have rainbow banding.

Fujitsu MB3514:

-Video is slightly darker than normal and also slightly more saturated. Edge pixellation is more noticeable with this encoder.

Sony CXA1645:

-Video is very bright and sharp, colors are very vivid.

FM Synthesis hardware used:

-VA0, VA1, VA1.8: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC
-VA2, VA2.3: Discrete Yamaha YM2612

Sound circuitry/sound quality:

-VA0, VA1, VA1.8: These use the same sound circuit found on VA7 Genesis Model 1s, meaning that the sound will be just as bad, but the quality varies depending on 2 chips in the console: quad op-amps used to amplify and mix the different sound channels. In general, the sound is worst when LM324 quad op-amps are used, resulting in heavily distorted sound that is sometimes so distorted certain low frequencies come out as squeaks. BA10324AF quad op-amps are the most common ones found on these Genesis Model 2s, which distort the sound, but not as badly as the LM324; essentially, the sound is identical to the VA7 Genesis Model 1, which uses the exact same quad op-amps. The best quad op-amps are the C324G, which do not distort the sound. The sound will still have a hissing sound in the background, however, no matter what quad op-amp is used. And again, the only way to be sure what quad op-amp is in your Genesis is to open it up and look at the motherboard. If your Genesis Model 2 contains a VA0, VA1 or VA1.8 motherboard, do yourself a favor and replace the on-board sound circuit by TmEE's Audio Mod. It will sound a lot better. Unlike the VA7 Genesis Model 1, the amount of hissing will always remain the same (in other words, at its absolute maximum) as there's no volume slider to control the volume of the audio output.
-VA2, VA2.3: The sound circuitry was changed in these motherboard revisions to account for the use of a discrete Yamaha YM2612, which all other Genesis Model 2 motherboards lack. The quality of the sound has greatly improved, but it's still not perfect. The sound no longer has a hissing noise in the background, but there are some volume balance problems with both motherboards. The main problem is that the sound coming off the YM2612, FM Synthesis, is too loud. This makes Genesis games that use PSG sound off, and speaking of PSG, it's pretty bad on both the VA2 and VA2.3 motherboards. There are 4 PSG channels in the Genesis: 3 square waves and one white noise. Two of the square waves are too quiet, causing Genesis games that make heavy use of those square waves to sound wrong. This is especially noticeable when playing Sega Master System games on a Genesis Model 2 that contains either motherboard as the sound will be off and heavily distorted. Sound coming off a Sega CD (PCM and CDDA) or Sega 32X (PWM) is also too quiet due to the YM2612's sound output being too loud.

Here's an audio fix you can perform to fix the bad PSG and make the YM2612 quieter so the volume balance matches that of a pre-VA7 Genesis Model 1. Refer to this schematic made by Chessage so you know what to replace: http://postimage.org/image/2lzbadko4/

1) Replace the 2.2Kohm resistors at R32 and R33 by 3.9Kohm resistors
2) Replace the 2Kohm resistor at R31 by a 2.2Kohm resistor
3) Relocate the 1Kohm resistor at R2 BEFORE the 2.2Kohm resistor you just added (doing this makes the audio louder while eliminating all distortion)
4) Replace the capacitor at C61 by a 1uF capacitor

The reason why the PSG is screwed up on both the VA2 and VA2.3 Genesis Model 2s is because the PSG is too heavily amplified. The location of resistor R2 makes it so that the sound is not only too quiet, but also distorted as two of the square waves are amplified more than the other square wave and the white noise. Relocating the resistor before R31 not only makes the sound louder, but also eliminates all distortion caused by R2 being placed after R31.

3/4 motherboard model:

When you flip this one over, you will instantly recognize it:




The metal plate ends further from the edge of the console than the full motherboard Genesis Model 2s. This means the motherboard is shorter, hence 3/4 motherboard. These are generally superior to full motherboard Genesis Model 2s, though they're harder to find.

Motherboard revisions: VA3, VA4

Video encoder:

-VA3: Sony CXA1145, Samsung KA2195D, Sony CXA1645
-VA4: Sony CXA1645

Composite video quality:

Sony CXA1145:

*no information yet*

Samsung KA2195D:

-Generally better than on older motherboards, but still susceptible to having vertical lines on the screen.

Sony CXA1645:

-VA3: Has a tendency to be just as bad as the KA2195D, complete with pixellation and vertical bars. Looks disgusting by CXA1645 standards.
-VA4: Just like a VA2 or VA2.3 Genesis Model 2 with a CXA1645, the picture is very colorful, very bright and very sharp.

FM Synthesis hardware used:

-All motherboards: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-All motherboards: A further revised sound circuit on these motherboards produces sound almost as good as a Genesis Model 1 that's got a VA2 to VA6.8 motherboard, but more muffled. The volume balance problems have been fixed on these motherboards.



Genesis Model 3



Like the Genesis Model 2, the casing is identical for all variants. This model has some compatibility issues, which includes Virtua Racing, the Sega CD, the Sega 32X, the Game Genie and any game that exploits improper implementation of TAS instruction in the Genesis (Gargoyles in particular), which the Genesis Model 3 fixed.

Compatibility fixes do exist, but performing them is rather difficult, and only one motherboard revision has been modified to the point of restoring all compatibility excluding the Sega CD and games that exploit improper implementation of TAS instruction.

Motherboard revisions: VA1, VA2

One way to determine what motherboard is in your Genesis Model 3 without opening it up is to try playing Virtua Racing on the console. If the PRODUCED BY OR UNDER LICENSE FROM SEGA ENTERPRISES LTD. screen shows up, you've got a VA1 motherboard. If you try to play Virtua Racing on a Genesis Model 3 with a VA2 motherboard, you'll just get a black screen.

An easier way to identify a VA1 motherboard apart from a VA2 motherboard is to do like with full-motherboard Genesis Model 2s: hold the cartridge slot open and inspect the traces at the front of the motherboard. This is what to look for in each motherboard revision:

VA1:



VA2 (ignore the IDE ribbon cable, that's part of the Game Genie and Virtua Racing compatibility fixes) :



Video encoder:

-All motherboards: Sony CXA1645

Composite video quality:

-The Composite video out of the Genesis Model 3 is simply beautiful. It's even sharper and brighter than Genesis Model 2s with a CXA1645, though depending on your TV's settings, the TMSS screen might be a bit smeared and the edge pixellation may be pretty bad. This is true of both the VA1 and VA2 motherboards.

FM Synthesis hardware used:

-All motherboards: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx GOAC

Sound circuitry/sound quality:

-VA1: Because the Genesis Model 3 is a cut-down Genesis, the sound circuit was revised to only output Mono sound, so you will not get any Stereo out of the Genesis Model 3 unless you replace the on-board sound circuit or send, for example, the LEFT audio output to the existing sound circuit and replicate the circuit for the RIGHT audio output. The quality of the sound doesn't suffer despite the revised circuit. In fact, the sound is clearer than any Genesis Model 1 or Model 2, however, the bass is a little weaker on the VA1 Genesis 3 than other models of the Genesis. It's like there's a bit of high-pass filtering going on.

-VA2: Like the VA1 motherboard, the audio is in Mono only and will only output Stereo sound if you modify the console. Overall audio quality is very close to the VA1 motherboard, but the bass is slightly heavier and PSG is slightly louder than normal. This works better for Mono audio as on earlier consoles, PSG would be drowned out a little bit when Mono sound used.



Sega CDX



As far as I'm aware, there exists only one motherboard revision of the Sega CDX, and it's generally quite good. Read on.

Video encoder:

-Fujitsu MB3514 (there might be other encoders in the CDX I'm not aware of)

Composite video quality:

-The video is sharp, but does exhibit some edge pixellation on certain graphics. The video is also darker and more saturated than other Genesis systems.

FM Synthesis hardware used:

-Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-The sound circuit used on the CDX is made in such a way that the sound practically comes out unfiltered, resulting in clean sound with rather weak bass. The sound output of the CDX is also quieter than other Genesis systems and the sound produced by the ASIC-based YM3438 is too loud. There's also some bass-boosting of sorts going on in the headphone jack as the bass is noticeably stronger out of the headphone jack than either the A/V out or the Line out, but the rest of the sound is unaltered.



Sega Nomad



Being as only 1 million of these things were ever made, only 1 motherboard revision exists.

Video encoder:

-Sony CXA1645 (there might be other encoders in the Nomad I'm not aware of)

Composite video quality:

-While the built-in screen on the Nomad isn't of very high quality, the Composite video of the Nomad is really nice. It's on the same quality level as non-VA3 Genesis Model 2s with a CXA1645, but with absolutely zero fringing.

FM Synthesis hardware used:

-Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-The Nomad uses a completely different sound circuit from the Genesis home consoles due to the fact the Nomad is a portable. The audio out of the on-board speaker is clear, but is very quiet and generally not all that good with almost zero bass and overall poor quality. The TV out, on the other hand, produces very similar sound to the pre-VA7 Genesis Model 1s, but the high frequencies are masked a little more. The big problem with the Nomad, and it may just be my Nomad, is VERY loud background noise in the audio output, both on the TV out and headphone jack. The overall sound is the same on both the TV out and the headphone jack except the headphone jack produces louder sound and is even noisier than the TV out (hissing plus electrical noise). PSG is also slightly louder on the Nomad.

Do take note that the Nomad, like the Genesis Model 3, has compatibility issues. Of course, since it's a portable Genesis, it can't be hooked up to a Sega CD. The Nomad is also unable to work with Sega Master System converters and the Sega 32X, but unlike the Genesis Model 3, it will play Virtua Racing. Compatibility fixes do exist to make the Nomad compatible with Master System converters and the 32X, however, I would advise not to bother with the 32X mod since you will not get the 32X's video layer on the built-in screen, only on a TV (unless the Nomad is your only Genesis. Just don't expect 32X gaming on the go).





JAPANESE HARDWARE:

MegaDrive Model 1

AV Intelligent Terminal/High Grade Multipurpose Use model



Like with the High Definition Graphics Genesis Model 1 in North America, the AV Intelligent Terminal/High Grade Multipurpose Use MegaDrive Model 1 in Japan has two different variants, but unlike the High Definition Graphics Genesis Model 1, neither model has TMSS.

There is a very subtle difference between the two models, which is found right next to the A of the Sega logo. If there is a little R symbol next to the A, that is the earliest model of the MegaDrive, the Japan-only model.

If, however, the Sega logo has no R next to the A like on my personal MegaDrive Model 1:



That's the first of the all-Asia NTSC models.

Motherboard revisions:

-With an R next to the Sega logo: VA0, VA1, VA2, VA3, VA4
-Without an R next to the Sega logo: VA5

Video encoder:

-All motherboard revisions: Sony CXA1145

Composite video quality:

-VA5: Like all North American Genesis Model 1s, the picture is bright and colorful, but slightly blurry. There is also a very slight instance of rainbow banding on the VA5 motherboard in the MegaDrive Model 1.

FM Synthesis hardware used:

-All motherboards: Discrete Yamaha YM2612

Sound circuitry/sound quality:

-All motherboards: Use the same Mono and Stereo audio amps as the pre-VA7 Genesis Model 1s in North America, so the sound will be clear and with very high bass.

Non-AV Intelligent Terminal/High Grade Multipurpose Use model

*no picture yet*

This is when TMSS was introduced into the MegaDrive Model 1 in Japan. If you find a Japanese MegaDrive Model 1 without AV Intelligent Terminal/High Grade Multipurpose Use written on the case, it's guaranteed to have TMSS.

Motherboard revisions: VA6, VA6.8, VA7

Video encoder:

-VA6, VA7: Sony CXA1145
-VA6.8: Sony CXA1145 or Fujitsu MB3514

Composite video quality:

Sony CXA1145:

*no information yet*

Fujitsu MB3514:

*no information yet*

FM Synthesis hardware used:

-VA6, VA6.8: Discrete Yamaha YM2612
-VA7: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-VA6, VA6.8: Use the same Mono and Stereo audio amps as the AV Intelligent Terminal/High Grade Multipurpose Use model, so the sound will be clear and with very high bass.
-VA7: Just like the VA7 motherboard revision in the North American Genesis Model 1 - hissy, muffled, distorted and generally very poor sound quality.


MegaDrive Model 2

*no information yet*




EUROPEAN HARDWARE:

MegaDrive Model 1

High Definition Graphics - Stereo Sound model:



While these High Definition Graphics - Stereo Sound models of the European MegaDrive Model 1 usually don't have TMSS, some of the later ones do. As of right now, there's no way to differentiate a non-TMSS High Definition Graphics - Stereo Sound MegaDrive Model 1 from a TMSS High Definition Graphics - Stereo Sound MegaDrive Model 1

Do take note of a few things on European MegaDrives:

1) They run in PAL and most games are not PAL-optimized, so they'll run slower than normal and the picture will be letterboxed.
2) Due to a slower master clock on European MegaDrives, every component in the system runs a bit slower than it should, and this affects the sound. Read on to find out how.

Motherboard revisions:

-Non-TMSS: VA3, VA4, VA5
-TMSS: VA6

(there might be other revisions I'm not aware of)

Video encoder:

-All motherboard revisions: Sony CXA1145

Composite video quality:

-VA6: Oddly enough, Composite video looks better on a PAL console than on any NTSC Genesis or MegaDrive. There's no rainbow banding or fringing and the colors are very vibrant, but the video overall looks blurrier than on an NTSC Genesis or MegaDrive.

FM Synthesis hardware used:

-All motherboards: Discrete Yamaha YM2612

Sound circuitry/sound quality:

-All motherboards: Again, these use the same Mono and Stereo audio amps as the pre-VA7 Genesis Model 1s in North America, so the sound will be clear and with very high bass, however, due to the slower master clock, the sound pitch is overall lower than on any other NTSC Genesis or MegaDrive.

Non-High Definition Graphics - Stereo Sound model:



Self-explanatory: a MegaDrive Model 1 without High Definition Graphics - Stereo Sound printed on the case. These models are guaranteed to have TMSS.

Motherboard revisions: VA6, VA6.8, VA7

Video encoder:

-VA6, VA7: Sony CXA1145
-VA6.8: Sony CXA1145 or Fujitsu MB3514

Composite video quality:

Sony CXA1145:

*no information yet*

Fujitsu MB3514:

*no information yet*

FM Synthesis hardware used:

-VA6, VA6.8: Discrete Yamaha YM2612
-VA7: Yamaha YM3438 with a modified DAC integrated within the Sega 315-xxxx ASIC

Sound circuitry/sound quality:

-VA6, VA6.8: Use the same Mono and Stereo audio amps as the High Definition Graphics - Stereo Sound model, so the sound will be identical to that model.
-VA7: Just like the VA7 motherboard revision in the North American Genesis Model 1 and Japanese MegaDrive Model 1, expect hissy, muffled, distorted and generally very poor sound quality.

Images courtesy of Socram8888.

MegaDrive Model 2

*no information yet*




That's the general rundown of nearly all Genesis and MegaDrive models. Feel free to contribute extra information concerning any and all hardware missing from this guide.

Update July 10, 2012: Slight cleanup, corrected some information on the Nomad and added new information on the Genesis Model 3.

[xbrinkx]

Good guide. I have the Model 2 (VA4 revision) with the CXA1645 encoder. The sound is very good and modding it for S-video is very easy.

[Ghaleon]

I think I'm gonna have to upgrade speeds through my ISP before I visit this thread again....12 pics @ 2272px × 1704px, wow.

[Ace]

That's what happens when you don't have a damn clue how to put pictures as thumbnails WITHOUT using the Attachment feature. I should resize my pictures in my future posts.

@Xbrinkx: Very nice, very nice. I'm sure yours didn't go through all the hell my VA4 did: failed attempt at turning it into a Neptune, broken trace, leaking capacitors, system instability, consistent resoldering... it was HELL! Took me 3 months to get it working properly again, and I took the opportunity to add a US/JAP region switch and S-Video.

[Metal_Sonic]

Mother of oversized images......

Great guide man, keep up the good work

[Flygon]

My mothers Mega Drive does not appear in any of those pictures, going by the cart slot.

Bottom of it:


Cart slot:



I'm sorry for my DSi being unable to take a high enough resolution screenshot, but I took it in the best conditions possible.

Taking apart the Mega Drive is out of the question, Mum would be worried I'd break it or something, but I can tell you that the video via RF is not half bad (Apart from the obvious issues with the RF unit blurring it a bit and introducing interference), but I am able to tell the pixels apart, probably even more so via the composite cable.

Anyway, the cart slot is significantly different from your images shown.

Also, the sound is nothing to write home about, probably one of the worse model 2's I've experienced, the one at my house is much better... or it could be the RF module, who knows. I wish I had my composite cables on me.

[kool kitty89]

I've seen several comments about the CXA1645 being easier to mod for S-Video, but what exactly does this mean. Will it tend to work with the "simple" (but not fully compatible) mod TmEE mentioned that just takes the raw luma and chroma signals off the encoder, adding just a 56-75 ohm resistor to the luma line? (or is it least more reliable for this mod, than the CXA1145 -which can sometimes work depending on the TV -I haven't tried it yet personally though)

[Ace]

@Kool kitty89: The simple S-Video mod on the CXA1645 is just a 75ohm resistor on both the Chroma and Luminance lines.

@Flygon: Full motherboard, bad sound, cartridge slot doesn't match any pictures... sounds like a VA0 motherboard revision to me.

Great guide man, keep up the good work

Thanks, Metal_Sonic!

[ooXxXoo]

I've seen several comments about the CXA1645 being easier to mod for S-Video, but what exactly does this mean. Will it tend to work with the "simple" (but not fully compatible) mod TmEE mentioned that just takes the raw luma and chroma signals off the encoder, adding just a 56-75 ohm resistor to the luma line? (or is it least more reliable for this mod, than the CXA1145 -which can sometimes work depending on the TV -I haven't tried it yet personally though)

The Sony CXA1645 encoder is far superior than the CXA1145....this last one, requires the video amp to get a full compatible s-video, while the CXA1645 only needs the 75ohm resistor and a coupling cap for each chroma & luma....
...
...
...

[TmEE]

Flygon does indeed have a VA0

[Ace]

Flygon, would you be able to take a clearer picture of the entire cartridge slot of your mother's VA0 MegaDrive II under brighter lighting conditions? I'll add the picture to the guide.

The Sony CXA1645 encoder is far superior than the CXA1145....this last one, requires the video amp to get a full compatible s-video, while the CXA1645 only needs the 75ohm resistor and a coupling cap for each chroma & luma....
...
...
...

The capacitors aren't really necessary. I didn't use any, and the S-Video works perfectly fine.

[ooXxXoo]

Flygon, would you be able to take a clearer picture of the entire cartridge slot of your mother's VA0 MegaDrive II under brighter lighting conditions? I'll add the picture to the guide.



The capacitors aren't really necessary. I didn't use any, and the S-Video works perfectly fine.

Your tv problably doesn't need them....But they are necessary...Just as the CXA1645 datasheet points them out.....
...
...
...

[Ace]

Hmm... very well. Once I get some extra capacitors, I'll add them in. May I ask why they're needed?

[TmEE]

I have a VA0 at hand, and a decent camera, i'll take some pics soon

[Ecco]

Very nice guide.

It allows me to confirm once and for all that yes, I do have the dreaded Genesis Model 1 with a VA7 motherboard!