Tectoy Megadrive motherboard revisions

[Bingo_Johnson]

Hello! THis is my first post. First i would like to show my apreciation for this site It has very useful information, and really sparked my interest in the Megadrive/Genesis back to life.

As a little kid i used to own a VA6, non-TMSS model 1 Japanese Megadrive that i played to death.

About two weeks ago, i received two boxed Tectoy Megadrive 2 as gifts from a friend. One has much better video and sound than the other. Influenced by the guide on how to tell MB revisions, i opened them up and took some photos, but could not identify them...

Maybe some of you folks can help me?

The odd thing is that the VA6 Jap Megadrive has worse sound/video than the two Tectoy Megadrives.

Here are some pics and descriptions:

Overall Case appearence for the two models (both have internal power supplies):



1st variant:

Crappy and distorted sound, background noise.



2nd variant:

Good sound, much better than the first.
Colors are much more vibrant on this system (both on composite video)

[m68k]

These are interesting boards. They seem to be a VA 3 or 4 board.
Never knew TecToy made the PCB for their megadrives, I just thought they rebadged sega parts. The second one is much older, it lacks the Sega On a Chip. (CPU and Glue/VDP on one chip). So the top one seems to be related to the late Genesis III's in architecture. While the second one looks like a VA3/4.

[Xeniczone]

The first one is a VA4 because it has the same chip (315-5960) as the VA1 Genesis 3. I've been looking for a VA4 Genesis. Any chance you want to sell it?

[ooXxXoo]

Aaahhhh!...The Brazilian Mega Drive III Marvel.....I've got a couple of them with the 315-5660 ASIC, I love how tectoy cramped in there the bi-volt power supply and RF modulator...

The first motherboard (pic 1) with the Sony CXA1645 encoder, you can easily tap s-video there....

The other motherboard rev, definitely does have an awful crappy audio....
...

[Ace]

1st variant:

Crappy and distorted sound, background noise.



2nd variant:

Good sound, much better than the first.
Colors are much more vibrant on this system (both on composite video)

The first variant is identical to a VA4 Genesis 2, but with dual 8-bit RAM chips instead of a single 16-bit RAM chip. The second looks like a VA3 with the sound circuit of the VA0-VA1.8 Genesis 2. I think you got your facts wrong with regards to sound; the sound amp on a VA4 motherboard is perfectly clean, but the VA0-VA1.8 sound amp is disgusting, with MAJOR hissing and distortion. It sounds awful.

[TmEE]

These boards are completely different from something like VA4, which I have 4... only thing in common between the VA4 and that is the same ASIC and sound mixing part, all else is totally different.
2nd one is inspired by VA0/1 when it comes to sound, all else is completely different.

anyway, thanks for these photos

[kool kitty89]

Are they both Mega Drive IIIs, or just the first one? I'd assumed the MDIII only used the integrated ASIC and omitted the expansion connctor (like a genesis 3, but in a model 2 case and with crappy sound). The second one seems a bit more like earlier model 2s with the separate 68k+Z80.

If I'm not mistaken, th eonboard AV out varied a good bit on the MDIII as well, some having RF only and some using a 5-pin DIN port -I'm not sure if any had the model 2's av port with full AV connections. (I assume that DIN-5 has similar pinout to the model 1 connector)

[ooXxXoo]

Nah...Both of them are Mega Drive III's.....The thing is, that tectoy have several revisions of it in their own. Like those posted here that include the exp port, while others don't have it at all, but instead, they have memory built-in games...All of them have the 9 mini pin Av port connector and RF mod on board, until the later change in the 2000's models (I also got 2 of these), Got the Mega Drive 3 "Cinza" model, with 60 built-in super jogos and the latest "White" MegaDrive 3, both having plain RCA outputs....

Edit: Here's one of my tectoy MegaDrive III's, note the missing exp connector and the added rom with the memory games behing the cart connector (10 in all)

[kool kitty89]

Huh, I remember seeing some tectoy product with a 5-pin DIN, maybe that was one of the Master Systems.

[Bingo_Johnson]

I think you got your facts wrong with regards to sound; the sound amp on a VA4 motherboard is perfectly clean, but the VA0-VA1.8 sound amp is disgusting, with MAJOR hissing and distortion. It sounds awful.

Yeah, I've got the facts mixed. The CXA1145 is the one that output good audio. To whoever asked, they where manufactured 1995, and 1996 respectively.

Also, this:

I've been looking for a HDG model 1 for quite some time, and i've come across 2 Genesis plus 3 3 button original controlers for around US$ 50,00. The seller will not sell them separated. However, the Genesis have not been tested with cartridges. The seller claims they will turn on, but don't have cartridges to test them.

One of the Genesis has got the long (FJ846USASEGA) serial number, which means non-TMSS. The other one, non-HDG, has a shorter FCC code.

Should i but them anyway, if only for the High Definition Graphics Glory?

[Ace]

Go ahead and do so. Just makes sure you keep an eye out on that non-HIGH DEFINITION GRAPHICS model, as it might contain a VA7 motherboard, which is absolute crap when it comes to sound quality(it's even worse than the MegaDrive III you have with the MB3514 encoder with MUCH heavier hissing). You can't go wrong with a HIGH DEFINITION GRAPHICS model, and if I were to find a lot of Genesis consoles that contains at least one HIGH DEFINITION GRAPHICS Model 1, I'd buy the lot right away.

[ooXxXoo]

One of the Genesis has got the long (FJ846USASEGA) serial number, which means non-TMSS.

Quick observation, from what I've seen, not all of the Genesis with this serial number are strictly non-TMSS systems....Great Genesis model either way, but just letting you know, so you won't be dissapointed....
....

[chinitosoccer]

Some pictures of what i like to call the "argentinian factory modded Megadrive III"

I cant tell what revision is, but one thing i know for sure... this piece of shit has awfull sound and video output.

[Ace]

That matches a VA0 Genesis 2 motherboard. This is one of the better VA0s, as the video encoder on it is a Fujitsu MB3514. It delivers dark, but good video output, although slightly pixellated. At least, you've got a better VA0 MegaDrive III than all of my VA1/VA1.8 Genesis 2s, which have NASTY video quality because the Samsung KA2195D encoder is used.

[kool kitty89]

Yeah, I've got the facts mixed. The CXA1145 is the one that output good audio. To whoever asked, they where manufactured 1995, and 1996 respectively.

I saw this a while back but never commented. The CXA1145 is the video encoder and has nothing to do with sound quality AFIK. The CXA1145, MB3514, and Samsung KA295D are the 3 encoders used on model 2s (and MDIIIs probably). The former 2 are OK with the 1145 being brighter and blurrier and the 3514 being dark but sharp; either can be adapted for S-video; these 2 are also the only ones used on model 1 MD and Genesis units.
The Samsung one is the most common and by far the worst, blurry and distorted with no S-video capabilities.

I don't think there's any corresponding audio trend with the video encoders used.