[ICEknight]

I just got this brand old Japanese Mega Drive:



And I was wondering which of the many versions available it could be.

According to this guide, this would be a:
-Mega Drive 1
-Japanese
-"AV Intelligent Terminal/High Grade Multipurpose Use" model
-With "®" next to the SEGA logo


And then:

Quote

Motherboard revisions:

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

So it would be something between VA0 and VA4...

I didn't see any "rainbow effect" as it's implied happens with models VA2 to VA5, so I guess it would be either a VA0 or VA1... or perhaps the rainbow effect isn't as noticeable on my PAL TV or something, so all I really know is that it's between VA0 and VA4. =\


Are there any other ways than opening the console to know the motherboard revision it may host inside?

Some things that might help tracking down the model:
-No "RF OUT" connection, just the one for composite.
-Controller has red paint in the A B C letters and a quite short cord.
-RESET button isn't as blue as the controller's START, but more gray-ish.
-I've come across some odd sound behavior in games like Revenge of Shinobi CD (v.3). When the music track "MAKE ME DANCE" is playing, the jumping sound effect (#00) seems to fuck up one of the instruments (at least when playing the level with the killer nuns, haven't checked this on the Sound Test).
-I've also noticed some slowdown in certain games (Streets of Rage CD), that I don't remember getting in my old PAL system... but then again, PAL systems are being continously slowed down.



By the way, is it known which official (unmodded) Mega Drives did have the best picture and sound quality of them all?

This post has been edited by ICEknight: 21 April 2012 - 12:39 PM

[TmEE]

no japanese machine has RF-out, which doubles the hardware revisions... almost


For MD1 there is :
VA0, VA1, VA2, VA3 ,VA4, VA5, VA6, VA6.8, VA7

Until VA4 there was no TMSS, VA5 has no TMSS in JP but in EU/US it has TMSS shown, any newer machine always shows TMSS.
VA0 and VA1 are JP only, there never appeared outside Japan.
VA2 is USA launch model
VA4 seems to be what EU first got
VA6.8 uses surface mounted CXA
VA7 is MD2 in MD1 shell

For MD2 there is :
VA0, VA1, VA1.8, (VA2 not sure if it exsits), VA2.3, VA3, VA4

VA2 uses toshiba ASIC and discrete YM
VA4 uses ASIC found also in Genny3 VA0 and 1

For Genny3 there is :
VA0, VA1, VA2

VA2 uses final MD ASIC also seen in Sega Pico, it also uses unified SDRAM controller and has VDP vscroll bug fixed. Nearly fully integrated.

[ReBirFh]

Under it the sticker says HAA-2500 or HAA-2510?
Does it have the modem connection in the back?

This post has been edited by ReBirFh: 21 April 2012 - 12:42 PM

[Meat Miracle]

What is the serial number?

[ICEknight]

It has no TMSS screen so it must be VA5 or earlier, and it has the Modem port, does that narrow down the possibilities?

I'll check the model and serial numbers next time I go to my parent's.


EDIT:

Quote

VA2 uses final MD ASIC also seen in Sega Pico, it also uses unified SDRAM controller and has VDP vscroll bug fixed. Nearly fully integrated.

Wow, so the Mega Drive had a bug in the VDP up until the very last version that was released? Does it affect any official games?

This post has been edited by ICEknight: 21 April 2012 - 02:36 PM

[Andlabs]

Yes; a number of games are affected by the fix, Kawasaki Superbike Challenge being one of them. I don't remember the exact specifics but the bug (a well known one) is that VScroll in the first cell colulmn isn't calculated correctly. The Genesis 3 also has this fix.

Does the Japanese After Burner II work on your MD? (I think I asked this elsewhere but eh)

This post has been edited by Andlabs: 21 April 2012 - 03:34 PM

[Sik]

Andlabs, on 21 April 2012 - 03:34 PM, said:

Does the Japanese After Burner II work on your MD? (I think I asked this elsewhere but eh)

Huh, no TMSS means all games should work (region lock-out aside).

[Andlabs]

wait derp stupid me

IIRC GerbilSoft posted information about board revisions on the wiki?

[GerbilSoft]

ICEknight, on 21 April 2012 - 02:26 PM, said:

Wow, so the Mega Drive had a bug in the VDP up until the very last version that was released? Does it affect any official games?

There's a few games that have workarounds for the VDP bug, so they "break" on the systems with fixed VDPs. One such game is Kawasaki Superbike Challenge:



The left image is how the game should appear (on consoles with the VScroll bug). The right image is how it appears on Genesis 3 VA2 and on emulators that don't handle the bug correctly.

Specifically, the bug is caused by incorrect handling of VScroll column "-1", which happens if the HScroll offset for a given line/tile/screen is not divisible by 16.

The easiest way to figure out what revision MD you have is by disassembling it and checking the system board. It's printed towards the bottom.

Andlabs, on 22 April 2012 - 02:19 PM, said:

IIRC GerbilSoft posted information about board revisions on the wiki?

Sega_Mega_Drive/Board_Revisions

Currently has scans of six board revisions:

• MD1: VA2 (USA)
  
• MD1: VA6 (USA)
  
• MD1: VA6 (PAL)
  
• MD2: VA1.8 (USA)
  
• MD2: VA1.8 (Asia)
  
• Gen3: VA2 (USA)

This post has been edited by GerbilSoft: 22 April 2012 - 02:38 PM

[Meat Miracle]

GerbilSoft, on 22 April 2012 - 02:34 PM, said:

The easiest way to figure out what revision MD you have is by disassembling it and checking the system board. It's printed towards the bottom.

Easiest but not 100% accurate is to check the serial, actually.

Though it's only accurate if 1. the sticker wasn't removed, 2. the case was not changed. And .8 subversions are not visible.

[ICEknight]

I was able to check the Serial Number today, and it's: 99N61029

I think the second digit ("9") means it was made in 1989, but that's all I can get from that number.


Also, if it helps, the model is HAA-2510.

This post has been edited by ICEknight: 28 April 2012 - 02:05 PM

[Meat Miracle]

Yup, indeed made in 1989, and it uses an old numbering system I have no info of. They changed to a standard format around 1990, where you could read board numbers right out of the serial. Before that, that letter had all kinds of letters in it. I'd guess VA0 or VA1 based on age alone.

It would be cool if you could take a photo, both from the serial and if you end up disassembling the thing.

[ReBirFh]

Sorry to interrupt but is there any interest in pictures of boards from other countries? I took pictures a few years ago of my 3 Tec Toy Mega Drives (MEGA DRIVE, MEGA DRIVE II, MEGA DRIVE III) I could upload it here or in the proper place.

[Meat Miracle]

There always is. Post away.

[ReBirFh]

MEGA DRIVE (BRA - TEC TOY)

- with Modem Port
- IC BD M5 USA VA3
- 837-7071







MEGA DRIVE II (BRA - TEC TOY)

- with Modem Port
- IC BD M5 USA
- 315-5402: VA5 / 315-5433: VA6






MEGA DRIVE III (BRA - TEC TOY)

- TE 0595 (2)
- PCI M.D. III c/RF Rev.02






MEGA DRIVE (CLONE?? - ASIA) <-- Not hard to find in Brazil and considered a high quality, perfect or almost perfect clone (Ace from SEGA-16 said it was a clone)

- without modem port
- Model Nº 1600-16
- Serial Nº 020012169
- MD-16M
- T010163

This post has been edited by ReBirFh: 28 April 2012 - 04:23 PM