Sega Saturn PCB revisions

Is there a list out there of the various Saturn PCB revisions (say "VA0") and which type of console you can find them in (say "Model 1 J-NTSC)?

I know for the genesis there is an extensive list comparing the graphics and sound of each board, but even a basic list for the Saturn would be cool.

 

Druid should have something written up somewhere by now :friendly_wink: and I'm sure he'll chime in shortly.
In the mean time there's this site over here.You'll need a translator, but it at least breaks them down a little.

Edit: Of course a serial tells a thousand words, and all the information is in the serial most of the time!

 

You can check the serial number for the official VA number of each board, provided that the machine didn't have cases switched. Serial number format is:
manufacturer code (1 or 2 chars) - year of manufacturing (1 number) - revision number (1 char, substitute letters beyond 9, so A for 10, B for 11, etc) - serial number (6 numbers).

Here's a database of the serials, you can sort it per hardware generation #, which corresponds to the boards VA number.
http://evilboris.sonic-cult.net/saturn/

Note that V-Saturn does not have the VA number in the serial (directly), and the Hi-Saturn NAVI and the Samsung Saturns don't seem to have them in the serial at all.
Also a rare few units have an extra 9 or Z between the date and the hardware revision: these are refurbished units.

The guide retrojunkie linked to uses made up imaginary version numbers.

 

Haha, it was just to keep him busy for a few hours until the real Saturn whiz showed up! :friendly_wink:

 

The site is cool, for some reason I can't enlarge the images but maybe that's just how it is. At least I know how to determine the revision. Is there a list that details differences such as power supply, boards but with real VA(x) numbers?

 

The pictures are just of the serials, and they work fine in all desktop browsers I tested. Tablets and phones and other such toys may not render them right.

For the per-board differences, I want to make a detailed guide once, but there are some ~30 different boards all in all, and due to my location it will be very expensive to get all revisions (shipping prices cost 3-4x as much as a console).

I've posted tons of stuff about things like different PSUs, what exactly do you want to know?

If you check Retrojunkies gallery, he has nice pictures of all PAL models up to VA5, NTSC models are similar to those minus some jumpers. VA6+ are the last single board designs all with minor changes per revisions up until VA15.

 

For the pictures on the site linked by the seconds poster (the one with fake version nubmers), for some reason I can not enlarge any of them. Only shows thumbnails of the different components.

There is nothing specific I am looking for, I mostly just love the saturn and want to know as much as I can about it. I have read through the genesis PCB revision guide multiple times and would love to see something similar for the saturn. It's also helpful to know which systems I can swap repair parts in / out of now that the saturn is older.

 

Second poster? That's me!
If you want some high resolution photos head over to here.
Just search Saturn and your dreams will be realised. Such fantastic looking hardware! :smile-new:

 

Love the pics! One thing I noticed, for the model one saturn, does that black glossy plastic piece that covers the access / power lights pop out? In the below pic it looks like only pressure tabs are holding it in.

https://picasaweb.google.com/101985...el1050054493?noredirect=1#5781268822502155410

 

Love the pics! Question though, on the model 1 saturn does that glossy black piece that covers the power & access lights pop out? It looks like its only held in with pressure clips.

 

It indeed does.

Do you have the manuals for the VA9 model?

 

Then, do you recall how many boards were mentioned in those? I think I already own one of each PAL board but it would be nice to have confirmation on that. As far as I know, there are VA0, 1, 3 & 5 (aka SD), 9, 7 and 13 boards, in that chronological order. VA9 has two PCB revisions, maybe more, but I've only seen two so far.

I'm asking for the VA9 manual specifically because that's one board that doesn't have the 837-x parts number printed on it, but I'm sure the service manuals would state that. It's a very odd board, doesn't fit in with the evolution of Saturn boards.

 

I guess it would make sense to have multiple units in the same manual. But the only boards significantly similar are more than a year apart in dates.

 

Sorry to slightly bump this thread, but this subject also interests me, as I am currently looking to acquire a Saturn which has the best picture/audio quality possible. I was hoping there would be a guide like "Ace's Mega Drive PCB Revisions Guide" but I haven't been able to find anything similar for the Saturn, so I just I had a few questions...

1) Do all Saturns use the CXA1645, or were different video encoders chips also used, and if so which one has the best RGB output?

2) Has anyone attempted swapping the CXA1645 video encoder for a CXA2075? According to the CXA2075 chip designer here:-
"There's ONE little catch, however. In order to attain the ultra-high
performance, we had to burn more power. This is not normally a problem (and I
don't know about most of the playstations) but the Sega that used the 1645
didn't have quite enough power budget (they used a fusable wire to supply
current to a few circuits) and our 2075 was over the power limit they had set.
I left Sony about that time after providing some suggestions for reducing
power for them so I don't know what they did with it at that point."
Sega ended up using the CXA1645 in the Saturn, but I thought it would be interesting if it could handle the extra power requirements of the CXA2075?

3) Is there any benefit to replacing any/all capacitors on the motherboard? (Unlike the Mega Drive and Dreamcast the Saturn's decoupling capacitors for RGB are located on the motherboard, not externally in the SCART cable)

4) Are there any technical differences between NTSC and PAL Saturn motherboards besides a few jumper locations, a different crystal oscillator, and C-Sync being replaced by +9V on the AV port? (Trying to dertemine if its worth importing an NTSC model)

5) Which version/manufacturers CD drive/laser is the most reliable?

6) I have read here that some later PAL models (VA7+) have interference present in the video signal, supposedly caused by the CD drive when reading a disk. Is there a known cause/fix for this?

7) I have also read that some versions of the Saturn have compatability problems when used with an XRGB-Mini, does anyone have more info? Specifically I believe some PAL models have problems with the sync signal when switched between 50Hz and 60Hz?

Thanks in advance for any advice

 

The Saturn is all-digital internally, and more importantly it used almost the same components throughout it's life, so it isn't affected by things the Megadrive is (like integrated YM2612 sounding different). You can use all models with confidence, there is very little, if any, difference between models. VA10+ models are incompatible with early revisions of two games, Space Harrier and Outrun, due to to using an ASIC 68k instead of a discrete one, but both games got later revisions that fix the issue. The video hardware was identical throughout its life, only benefiting from a presumable die shrink (presumed only due to the IC labeling scheme, in reality I have no clue what was their difference).

1)
Most Saturns use CXA1645M, but usually later models use different parts. I've seen MB3516A on later japanese models and a BF... something or other on PAL model 2s. It differs mostly by the production run however, as they are all pin compatible, they used whatever ones were on hand I guess (there are some later PAL model 2s, which still used VA9 boards, but had used CXA1645Ms, despite earlier ones using that BF-something chip).

The only part that actually was changed is the d/a converter. TDA1386T in most models, PCM1710U (pin compatible) in some others, PCM1717E in the later motherboards with a smaller form factor. The smaller form factor was used on VA10+ boards, I think (VA11 and 13 for sure, don't know VA10 and 15 from the top of my head). This is however irrelevant if you are obsessed with the best quality since you can tap the SCSP directly to create s/pdif digital output.

I recall my VA13 PAL model having slightly blurrier picture, but this could be attributed to a thousand things not related to the actual motherboard (aging caps, cable quality, I only checked it on my plasma, etc), even to me being tired when checking that one very late model.


2)
I don't know about the CXA2045M. From what I read, it is meant to drive very high resolutions and require less external filtering, and it was available from 1996 onwards. So they couldn't really use it on a 1994 console, and later post-96 revisions did not change to this encoder either. Probably a situation of "if it's not broken, don't fix it". Later on, the Dreamcast used it's own sega custom video encoder.

3)
Outside the general benefits for replacing aging caps, I think none.

4)
Beside the ones you mentioned, the three pal/ntsc selection pins are interlinked differently depending on motherboard. There are three of them, the PLL pin 1 (main oscillator selection), VDP2 pin 79 (50/60hz output), and CXA1645 pin... uh,7 I think (PAL/NTSC color encoding). Only relevant if you do a 50/60 mod and end up with a rolling image, in which case the PLL is switched to the wrong frequency mode.

5)
All of them. Seriously.

6)
I have ~15 or so Saturns and I specifically want to get all the different motherboards for a visual guide, and so far the ONLY perceptible visual difference in the video output I noticed was the rippling in VA7/9/13 PAL units. My USA VA7 model does not have that, so I can only guess that the power supply causes some sort of interference or feedback. This causes a slight ripple to the right at the top of the picture, and random lines rippling when the cd drive is loading. However I've only seen this on my plasma tv, on old CRTs I did not see this problem. It could be the shortcoming of modern TVs and not the Saturn.

As I recall swapping the power supply to a 110v one fixes it. But it's been a while since I tested. I really need to write all that down.

8)
No idea about that. The Saturn does switch resolutions from 320x to 352x modes, and I read on the Framemeister wiki that it can't instantly re-capture the signal, but it makes it sound like an issue that could be fixed in future firmware updates. Also I recall the xrgb having issues with PAL signal in general but also that the Framemeister had those fixed? I seriously don't know, you should check the xrgb wiki for more info.

 

Thanks very much for you detailed reply Druid II

I have been doing some more research since you posted your message and your name pops up alot regarding the Saturn! It would be great if you could write a revision guide sometime with all your findings. I just have a few follow up questions if you dont mind! (I have numbered them below)

1) Hmm, thats interesting. Might the the 'BF' encoder actually be a BH7236F? (ROHM manufactured video encoder) Also do you know which VA revisions it was used on? and was it only used on Saturns manufactured in a specific country? (China, Indonesia etc)

2) I'm not really into s/pdif mods, so would be curious to know if one d/a converter is considered better than the other?

Thanks, this is exactly the sort of detail I love to know!

You probably already know this, but the Dreamcasts custom video encoder 'SEGA 315-6258' is actually made by ROHM and the real part number is BU1426KS (No datasheet since its a custom part, but the pinout is on the released Dreamcast VA0 schematics)

3) Do you know if Sega used high quality/good brand capacitors in the Saturn, or just whatever was cheapest? I know many Mega Drives and Game Gears are affected by cheap/poor quality capacitors so wasn't sure if the Saturn was affected too. I realise replacing aging capacitors in general can help, but I would be more inclined to replace them if they were of poor quality to begin with - if that makes sense.

4) Are all three pins controlled by one jumper location, or would they all need to be seperately switched (Including the crystal) if I wanted to switch between 'proper' NTSC and PAL modes?

Thats good to know, in my experience I tend to find the Samsung lasers fails more often in the Dreamcast than the Yamaha ones. This is just anecdotel evidence though, especially since the Samsung drives seem to be much more common than the Yamaha's.

5) Hmm, so given that retro said there were three Saturn PSU revisions based on the Sega service manuals:-

It sounds like the A and B PAL PSU revisions are fine, but the C revision may be causing some ripples in the picture?
Alternatively perhaps the rippling is due to the extra +9-12V power line for SCART switching present on PAL PSU's?

6) I found this info on the XRGB wiki, which refers to Mega Drive's, but I believe the same issue applies to the PAL Saturn as well:-
http://junkerhq.net/xrgb/index.php/Sega_Genesis

I previously found posts on the shmups.system11.org forums mentioning this issue, but I cant find them now :/
Perhaps its been fixed with an XRGB firmware update, but if not I just wanted to be sure I wasnt at a disadvantage by buying a PAL Saturn?

----------------------------------------------

7) I personally prefer the look of the Model 2 Saturn slightly more than the Model 1, so if there isnt any major quality differences between them, then I think I would be best to look for a PAL Model 2 VA5 "SD" - any thoughts?

Thanks again Druid II