Sega Saturn PCB revisions

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Thanks, I noticed that site linked in one of your earlier posts, really handy resource although it took me a minute to work out the best way to sort the results!

Shouldn't be too much of a problem, since I will be using a homemade SCART cable which has individual shielding for each video/audio signal

I have just uploaded them to my dropbox for you, hopefully you can download them now:-
https://dl.dropboxusercontent.com/u/38801046/DREAMCAST VA0.rar

So its the first 'A' type PSU that was used on VA0 that has problems? Thats interesting as I just came across this Japanese site which describes a lot of Saturn differences:-
http://nannanseisaturn.web.fc2.com/segasaturn/
It shows that the original Japanese Saturn was designed to have a place for a fan just next to the PSU, the 'A' type power supply PCB even has a cut-out at the front to accommodate the fan.

Its a shame they didnt use one standard jumper location :/
I also read that the VA5 "SD" version has VDP2 Pin 79 connected to ground underneath the chip so you have to lift the leg for a 50/60Hz mod? <THIS INFO IS INCORRECT, IGNORE THIS.
(I just always prefer using the original jumper locations if possible)

Interestingly the Japanese site I linked above seems to think the Sanyo drive isnt as well designed as the JVC drive. Translated it says "This is Sanyo pick-up unit. Portion to be sliding is in plastic. Bad feeling."

Hmm, what about swapping the 240V PSU for a 110V PSU, and then using a stepdown - wouldn't that be a possible way to test if its the extra +9V line causing the ripples?

Sounds good, looks like I will be getting a PAL VA5, thanks! Just a few more questions...

If I was looking for an NTSC model, what VA would you suggest?

Do you have any idea why the VA5 "SD" doesnt actually have VA5 printed on the motherboard?

In one of your previous posts you said "VA9 has two PCB revisions, maybe more, but I've only seen two so far." but i'm not exactly clear what that means. Surely if there are two PCB revisions they should be labelled VA9 and VA9.1? After all a different PCB revision usually means a different VA number?

One last question - if I replace the BIOS with a region free version would it be best to use the USA or PAL BIOS? Are there any differences apart from the on screen BIOS revision letter? and are both compatible with 50Hz/60Hz modes?

Thanks again Druid II

 

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Thanks Druid II, after searching on ebay I have managed to find a Model 2 VA5 Saturn (Serial starting 'AD65') and its on it way to me now

Having asked a number of sellers for the first part of the serial number to identify the revision, I found it interesting that five Saturns from different sellers that were listed as faulty (Problems reading disks) All had serial numbers starting 'AD69' so were VA9 models made in Indonesia. Probably just coincidence, but I thought it was interesting.

Just to go back to your point here:-

Would the below list be correct for PAL models?

-PAL SATURN MOTHERBOARDS-
VA0 - All three pins separated
VA1 - VDP2 pin 79 and PLL pin 1 interlinked (Fix to enable use of 'SW4' can be seen here)
VA3 - All three pins separated
VA5 - All three pins separated
VA7 - All three pins interlinked
VA9 - All three pins interlinked
VA13 - VDP2 pin 79 and Video Encoder pin 7 interlinked

Just to confirm, to perform a 50Hz/60Hz mod on a revision that has some/all of the pins interlinked (VA1, VA7, VA9, VA13) it would be necessary to cut traces, so that only VDP2 Pin 79 is switched by the jumpers (Or alternatively lift VDP2 Pin 79, which is quite risky) Unless you also swap the X1 crystal to completely change the systems between 'proper' NTSC/PAL, rather than just 50Hz/60Hz.

Also, do only VA0-VA5 have pads present for SW4 on the PCB? and do you know of a specific switch/part number which would fit on the existing pads without modification/using wires?

Lastly, I noticed this picture which shows that the last pin of SW4 also connects to Pin 7 of the video encoder, is that correct? and if so is Pin 7 already grounded elsewhere?

This is from the French guide here:-
http://www.segakore.fr/articles/switch_sat_p2.html

The PSU changes remind me alot of the original Xbox, it would be great to someday get a visual guide to all the Saturn PSU types/manufacturers for reference.

Hmm, what about using a small piece of plastic to insulate the +9V pin/contact on a 240V PSU to see if the ripples disappear?

One final question, I noticed on the released VA13 schematics that on the "Diagrama de Blocos" pdf the NTSC crystal frequency is labelled as '14.318 MHz', which makes sense as that is a multiple of 3.579545 MHz needed for NTSC. However on the "Conjunto PCI VA 13_06" pdf the X1 crystal is '14.302446 MHz' which is quite different. Which crystal frequency is correct for an NTSC Saturn? and what frequency did they use for PAL Saturns? (I'm going to try my luck with a 50Hz/60Hz switched PAL model first, but if I experience video stutter using an XRGB it would be good to know the parts required to convert it to proper NTSC)

Thanks again Druid II, I feel a lot more informed about Saturns now thanks to you

 

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Is pot tweaking fairly successful on Saturn's with problems reading disks? I have had some success with Dreamcasts, but recently attempted to pot tweak a few Wii's and was completely unsuccessful and in the end I just replaced the lasers :/ If any of the faulty Saturns had been 'AD65' VA5 models I probably would have bought one though.

Sorry, I should have been clearer - I meant on the PAL VA7/VA9 models (and PAL VA1/VA13 with one additional link) you should be able to switch to 'proper' NTSC fairly easily since most/all three pins are already interlinked, so you just need to additionally swap the crystal (Whereas on the VA0/VA3/VA5 models you would have to switch all three pins seperately and the crystal)

Ok, I just thought that the PCB designers most likely had a specific switch model in mind, so it would have been nice to use the exact type intended if possible.

Great!

Well I just thought it was interesting that the ripples are apparently only visible when connected to certain TV's - makes me think certain TV's may be somehow 'causing' interference/power drain on the +9V line straight to the Saturn's PSU, which might cause the PSU to struggle when more power is required to read a disk...just a random thought I had.

Doh! I already knew the schematics were from TecToy in Brazil, so should have remembered that they use PAL-M.

I read your post that said VA2/VA3 are identical to VA4/VA5 - does that mean that the VA4/VA5 revisions were only produced to accomodate the Model 2 design?

Also, just for reference do you know which motherboard revisions used 20pin drives, and which used 21pin drives? All the sites I have found just say Model 1 = 20pin, Model 2 = 21pin, but thats not really specific enough for me.

Oh and I came across your posts here and here regarding two different official Sega Saturn SCART cables, and I also believe the SCART cable with a standard SCART plug (No screw) thick cable and two ferrite cores is an official cable, despite there being no logo/model number on the plug. Whilst searching ebay I noticed a number of Saturns came bundled with this type of SCART cable, far too many for it to be an aftermarket cable. In addition one auction for a brand new/unused Saturn had this picture:-

If you look carefully at the SCART plug you can see that this this Model 2 was packaged with this type of SCART cable. I cant seem to find a Sega model number for the Saturn SCART cable though, does it have one?

Thanks again!

 

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Thanks. Just for reference do you know which motherboard revisions used 20pin drives, and which used 21pin drives? All the sites I have found just say Model 1 = 20pin, Model 2 = 21pin, but thats not really specific enough for me (Does VA2/3 use 20pin, and VA4/5+ use 21pin FFC connectors?)

Thanks again for putting up with all my questions Druid II

 

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Love going away on vacation and coming back to detailed replies to a thread I started, great read!

Personally, though I own a few, if I were to just buy one and only one Saturn it would be the original VA0. It has (what looks to be) the easiest BIOS chip to solder and replace with a region-free BIOS, as well as the newer mod chips allow the model 1 saturns to be modded without any soldering. They are easier now than the model 2's.

 

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Here vignettes expand without problems?
may be necessary it is registered?
anyway you ca will give access to the download area


and I remember that my method is not academic is an extension to learn very quickly how and what modchip switch frequency can be installed

ici les vignettes s'agrandissent sans problémes ?
peut etre faut il est inscrit ?
en tout cas ca te donneras accés a la zone de telechargement


et je rappelle que ma methode qui n'est pas academique est une vulgarisation permettant de savoir tres vite quel modchip et quel switch frequence on peut installer