Looks good so far! If the disc doesnt spin or it says the drive is empty, make sure that the metal pin the door moves when it closes is making contact in the closed position.
Thanks! In part two I will cover replacing the laser and adjustments etc. I believe the laser diode has died and as a result it doesn't see the disc at all. Thanks for the advice, the door switch has been previously taped by whoever owned it in the past - presumably so they could do the disc swap trick. When I put a disc in the laser does move (after I have moved it) to the correct sector but there's just no laser. I've adjusted the pot both ways and no signs of life in the laser. Touch wood the laser assembly I've ordered will fix it. Will get part 2 up soon =)
hi, i bought a second hand Saturn console online. i check the label at the back, showing AC 100V 50/60Hz 12W, so i bought a voltage transformer to decrease 240v to 100V. the console is connected to a ransformer via power cable and then to powerpoint, i heard a tiny sound "bomb" shortly after i press start button. i dont know whether i select a wrong transformer or something wrong in a console itself. PS： Transformer input 220-240V Max1200W,50HZ, output 100V. i wpuld like to know main cause, thanks
@@GadgetUK164 I have tested the output voltage of the transformer which is actually 224 v via multimeter. therefore, this is why I heard a tiny sound shortly after the console is plugged in.
Ι just bought from a friend of mine a model 2 pal saturn but I have an issue. It power's up just fine its reading discs also the problem is that it presses buttons by itself. It presses up, left, start for sure and it might presses x, y, z. It's not a controller issue because I ve got 2 and both works just fine with my other saturn also it does that even without controller plugged in at the console port. When I turn it on (with old battery) it goes at date and time menu but it starts changing the time by itself I press right and A button I go to exit and then if I ve got cd inside it starts loading, I press start from controller and the game starts just fine BUT the problem with pressing buttons still remains. I tear down the console Ive cleaned it properly and I ve checked the capacitors (with my eyes cause I don't have esr tester) from motherboard for leacks or if someone is ready to blow and it seams to be fine. I also replace the battery with a new one but I have to mention the fact that the previous owner had the console stored for 4-5 years and when he try to turn it on he started the console without battery at all for about 3-4 times (I dont know if this has anything to do with the problem but I just mention it for the record). Any ideas anyone?
It could be a faulty IC on there then. You need to trace where the connections from the controller sockets lead too. The first chip those signals land on is likely the fault. But it's possible that capacitors are causing this.
Just subscribed. Your Dreamcast teardown got me to Purchase a Dreamcast. I paid $31 USD total for a working unit with cables, controller, and VMU. Now i went and impulse bought an untested Saturn without AV cable, come to see if you did a teardown of one and it looks like we were in the same boat XD. Cheers man.
+LazyJackal That's a good deal considering it came with cables, controller and VMU as well =D Let me know how you get on with the Saturn! Most of the time with the Saturn its usually either the laser, the BTL driver (if it has been hot swapped abused), or caps on the motherboard.
Well the Dreamcast needs a good retr0bright treatment. The Saturn does seem to work, its a VA7, a little scratched up. but it had never been opened before, Clean as shit except a dusty laser. Again, about $31 USD including controller, AC adapter, and shipping. The moral of the story kids, is that "Untested" on ebay could just mean they have no games to test it with. Or it could mean Billy poured a soda down the cartidge slot. You never know.
+GadgetUK164 I have a similar problem with the Saturn I bought a year and a half ago sometimes nowadays it wont spin the disc and would make a few weird noises while spinning it sometimes it says the disc drive is empty and i have to switch it on and off a couple of times and change discs to get it to read a disc properly. Any Suggestions Iam also not good at soldering the best i could do is replace the dreamcast internal battery (which is considered a bit hard for me)
+sa97 inc I wonder if its a capacitor issue maybe? Have you inspected the SMD electrolytics? There's a chance if your laser I guess? Have you tried adjusting the spindle height to raise or lower the CD vs the laser?
+GadgetUK164 I haven't tried any of the suggestions above I also noticed that it mostly happens when i first turn the system on If you want I can upload a video for you for how the disc spins when i encounter that problem
Hi, then. Can you give a hand, pls? I've got a Skeleton model Saturn, I've just changed the laser board and lens, and its working very well while the console is open. When I close everything the disc just wont spin. Opened console works, closed dont. Can you imagine why? Thanks a lot
Sounds like a bad connection somewhere?!? I would make sure the lid switch is not the problem - sometimes that kind of thing could cause the problem you've described.
I installed a Switchless region mod in my sega saturn and now I just get a black screen, disc wont spin or anything. Any idea what might cause this? I followed the instructions to a tee, the correct traces were cut, all solder joints have been double checked so not sure what could have gone wrong?
If in doubt, undo the mods and re-test without them. Perhaps you could the wrong trace or something like that? Or perhaps there's a solder bridge somewhere near the mods? It could also be something not connected up properly somewhere?
Hey buddy, what 2 pin holes are you using out of the A/V connecter. I have a Saturn but no cable. I know there only a couple of quid but seeing you do that i can just make one to play a quick couple of games on. Cheers.
+craig gilchrist So wait, is it one solid piece of metal connecting the two pins 8 and 11, then both leads crimped/soldered onto the metal? Or is it two single pieces, each one soldered/crimped to a lead from the composite cable?
I have a Sega Saturn board VA0 like yours and I get no video output. My TV detect a signal but black screen. The CD is spinning normally. Any idea what could be wrong ?capacitors? My AV cable is fine as I I tested it with another console.
It could be down to bad SMD capacitors - check they aren't leaking (the Japanese ones it is more common to occur). Also measure the voltages coming out of the power supply. It might be caps on the PSU. Be careful when measuring as there are high voltages on the PSU board. Also worth checking your video cable and where it plugs into, just to rule it out.
You wouldn't happen to know the size of the screws that hold the case together would you? I picked a Saturn up that had no case screws. Works fine though!
Hi, I am not sure at the moment but I will take some close ups later if that helps? There's also the service manual here which will likely mention exact screw sizes:- console5.com/techwiki/images/3/39/Sega_Service_Manual_-_Sega_Saturn_%28PAL%29_-_No._013-1%2C_June%2C_1995.pdf
Looking at the service manual I think it's part 43:- 43 029-000035-0B B-TITE SCR PH BLK 3X10 Presumed the 3X10 is the size? Hard to tell, also not sure if the revision that service manual is based on is the same revision as yours (and mine).
My Saturn as been acting really odd with displaying the game's graphics There are times where the game doesn't load at all, the graphics are glitchy or some graphics are missing. you did mention around 9:00 that the 315 5688 and 315 5690 chips are for displaying the graphics. Is there a possibility to change those chips?
Yes, you could change the graphics chips, but hard to do. The SH2 processors also generate 3D graphics. Missing or corrupt graphics is most likely either a cap issue on main board or a glitchy SRAM either on main bus or perhaps on SH2 bus.
Also worth checking out the capacitors on the PSU - be careful as you can get a nasty shock from the main DC smoothing cap on there, and obviously make sure power is disconnected from mains before you take the PSU out.
8:17 I was first going to comment and say "What kind of muppet replaces a fuse with a jumper wire??", but I'm not that sure anymore that it's not factory standard. It's difficult to estimate the thickness of the jumper link from that camera distance, but such a jumper could act as a fuse given the dimensions are exactly calculated and/or tested. Or, the designers might have decided to skip the fuse to cut costs and just go for a jumper link instead. The reason I'm suspecting that it might not be an ugly user fix is that the soldering looks pretty decent, and I would suspect that someone who makes such a stupid decision as to replace a fuse with a jumper wire is probably not very skilled at soldering either. Also, I don't see any silk screen markings for the fuse. It only says "fuse", and there is no symbol for it where the fuse should go, as there are for the other components. When populating with actual components, it's common to designate each given component a certain number. So even if there were only one fuse on the board in the form of a real component, it would make more sense to call it "F1" instead of just "FUSE"... hence my suspicion the jumper link is mounted like that in factory.
Hehe, yes, I did wonder initially if someone replaced the fuse, but as you say - It looks like a wire link done at manufacture. I think they changed the design and decided not to add a fuse. The wire is pretty thick, I mentioned on the video it might take 3 amps or so to blow, but looking at the thickness I suspect it would take a lot more and I don't believe it's designed to be a fuse as it stands. It could be designed to allow isolation of that part of the board. I know if some systems (Lynx is a good example) they designed it whereby each section of the logic can be isolated from VCC by removing a single inductor or wire link.
I think I will have to agree with you there; the jumper link in this video doesn't look like a fuse at all. It's difficult to estimate the exact size from the video, but it can probably carry a lot of current. I guess it might be a problem if it couldn't since we would then have a big voltage drop across the jumper which is not good at all. But regardless of the fuse on this particular board, it's not a completely uncommon technique to use a small strand of wire to temporarily replace a blown fuse during troubleshooting of a board. Blowing up strands of wires in the case of a short on a board can be a lot cheaper than having to replace fuse after fuse until the short is finally found and repaired.
i knew earlly japanese saturns had the different psu mounted to the top of the shell but i have never seen or knew they made them in the western model, interesting.
Yes, it's very strange isn't it! I've seen quite a few pictures and videos where the PSU is mounted on the lower part of the case rather than the top part.
The only Sega Saturn to use the top mounted psu is the va0 motherboard, the very early ones. Everything was changed for the va1 where it's more familiar to what a model 1 Saturn is. And the va2 and va3 changed the cd drive from 20 pin to 21 pin, va4 and va5 are the first model 2 saturns.
See here - gamesx.com/avpinouts/saturnav.htm You need comp video, and ground to get a composite video signal out to your TV. I just tested by feeding the wires from a composite lead into the relevant connections on the AV port there.
Can you please help me? The console is VA 0.8 USA. I power the console and I can set the language, but the selection box is not present. After that I can set the clock. After this I get the "saturn" white text, but the big blue saturn logo is missing. Followed by a black screen. I can boot the pseudo saturn from the cart slot, but it just hangs when starting the cd. I made a cart with the saturn test menu (hiddenpalace.org/Sega_Saturn_Test_Menu_v1.0f). But i just get black screen after "licensed by sega". I removed the bios and I installed a region free one. No differences. I replaced the working ram at IC3 and IC4 without any difference. I replaced the working ram at IC31 and IC32 and no difference. If the ram at IC32 is removed, the console acts the same. And yes, this ram has all the connections to IC6 ok. I've also checked all the connections on ECABUS and ECDBUS. The board doesn't have signs of corrosion.
I presume you ruled out the drive by swapping with one from another Saturn - just to rule it out? PSU is unlikely here, but have you measured the voltages from PSU to make sure one is not low? Assuming you've done those things and the fault is the motherboard, I would normally suggest caps on a JPN / US model - but you've checked those already. That leaves, RAM, processors, arb / custom chips. Are there any clues from anything getting hot? Looking at the only schematics I have (perhaps not the same rev as your Saturn) - I see a load of 74LS245's. I would blitz those next, swap them for new chips and see if that solves the problem. Also consider the ROM may be the issue. Beyond that, I suspect it could be a broken trace somewhere that you've missed, or a faulty custom chip (one of the 315-blah parts, large QFP chips). The only way you could find a fault like that is by scoping the various buses and control signals, or using a logic analyzer (but that would be incredibly difficult as the Saturn is packed with hardware). Slim chance one of the processors is the issue, 68K, SH-2 etc.
@GadgetUK164 - Retro Gaming Repairs & Mods The power supply is ok. I've tested in an identical va 0.8 console (i have many motherboards and only one psu). I've read somewhere that the console perform some tests before the logo. Maybe that's why the logo is missing. Any ideas? I doubt that any custom ICs are bad.
I pm'ed you regarding Speccy 48k ram chips, did you get it? Also have you seen this, EBay item 281138097707 no, read what it does it sounds interesting
That cassette adaptor looks interesting, but I've had bad experiences with turbo loaders and these adaptors (and MP3 for that matter). Will take a look at the PM now.
+steve5123456789 Hmmm, assuming the PSU didn't fry the motherboard, I would first swap out the PSU with a european PSU. Chances are it might work after that. I've no idea what damage may have occurred on the PSU though.
Yes, the PSU is modular - they output the same voltages but both take different input voltages. A Japanese Saturn PSU expects 110v to 120v. A Euro Saturn expects 220 to 240v. Both PSUs output the same voltages to the motherboard, regardless of their input voltages. Make sure you get the same model - there are 2 PSU types. Model 1 Saturn has PSU screwed into top part of case. Model 2 Saturn has PSU screwed into bottom part of the case.
![Sega Saturn Laser Repair / Replacement [SH no.1]](http://i.ytimg.com/vi/sDS6dS_sTFc/mqdefault.jpg)
Part 2 - ruclips.net/video/NDgU1dpC6dE/видео.html
Part 3 - ruclips.net/video/CTc9W9cw1bQ/видео.html
Looks good so far! If the disc doesnt spin or it says the drive is empty, make sure that the metal pin the door moves when it closes is making contact in the closed position.
Thanks! In part two I will cover replacing the laser and adjustments etc. I believe the laser diode has died and as a result it doesn't see the disc at all. Thanks for the advice, the door switch has been previously taped by whoever owned it in the past - presumably so they could do the disc swap trick. When I put a disc in the laser does move (after I have moved it) to the correct sector but there's just no laser. I've adjusted the pot both ways and no signs of life in the laser. Touch wood the laser assembly I've ordered will fix it. Will get part 2 up soon =)
hi, i bought a second hand Saturn console online. i check the label at the back, showing AC 100V 50/60Hz 12W, so i bought a voltage transformer to decrease 240v to 100V.
the console is connected to a ransformer via power cable and then to powerpoint, i heard a tiny sound "bomb" shortly after i press start button. i dont know whether i select a wrong transformer or something wrong in a console itself. PS： Transformer input 220-240V Max1200W,50HZ, output 100V. i wpuld like to know main cause, thanks
It's possible that it was already partly faulty before you got to it? ie. maybe someone powered if previously with the wrong voltage?!?
@@GadgetUK164 I have tested the output voltage of the transformer which is actually 224 v via multimeter. therefore, this is why I heard a tiny sound shortly after the console is plugged in.
@@GadgetUK164 I don’t know if the console can be fixed
Ι just bought from a friend of mine a model 2 pal saturn but I have an issue. It power's up just fine its reading discs also the problem is that it presses buttons by itself. It presses up, left, start for sure and it might presses x, y, z. It's not a controller issue because I ve got 2 and both works just fine with my other saturn also it does that even without controller plugged in at the console port. When I turn it on (with old battery) it goes at date and time menu but it starts changing the time by itself I press right and A button I go to exit and then if I ve got cd inside it starts loading, I press start from controller and the game starts just fine BUT the problem with pressing buttons still remains.
I tear down the console Ive cleaned it properly and I ve checked the capacitors (with my eyes cause I don't have esr tester) from motherboard for leacks or if someone is ready to blow and it seams to be fine. I also replace the battery with a new one but I have to mention the fact that the previous owner had the console stored for 4-5 years and when he try to turn it on he started the console without battery at all for about 3-4 times (I dont know if this has anything to do with the problem but I just mention it for the record). Any ideas anyone?
It could be a faulty IC on there then. You need to trace where the connections from the controller sockets lead too. The first chip those signals land on is likely the fault. But it's possible that capacitors are causing this.
@@GadgetUK164 Thanks for everything, I ll check it both and if I finally fix it I will come back to mention the issue. 😉
Bro, part 2 please
Part 2 - ruclips.net/video/NDgU1dpC6dE/видео.html
Part 3 - ruclips.net/video/CTc9W9cw1bQ/видео.html
Just subscribed. Your Dreamcast teardown got me to Purchase a Dreamcast. I paid $31 USD total for a working unit with cables, controller, and VMU. Now i went and impulse bought an untested Saturn without AV cable, come to see if you did a teardown of one and it looks like we were in the same boat XD. Cheers man.
+LazyJackal That's a good deal considering it came with cables, controller and VMU as well =D Let me know how you get on with the Saturn! Most of the time with the Saturn its usually either the laser, the BTL driver (if it has been hot swapped abused), or caps on the motherboard.
Well the Dreamcast needs a good retr0bright treatment. The Saturn does seem to work, its a VA7, a little scratched up. but it had never been opened before, Clean as shit except a dusty laser. Again, about $31 USD including controller, AC adapter, and shipping.
The moral of the story kids, is that "Untested" on ebay could just mean they have no games to test it with. Or it could mean Billy poured a soda down the cartidge slot. You never know.
+GadgetUK164 I have a similar problem with the Saturn I bought a year and a half ago sometimes nowadays
it wont spin the disc
and would make a few weird noises while spinning it
sometimes it says the disc drive is empty
and i have to switch it on and off a couple of times and change discs to get it to read a disc properly.
Any Suggestions
Iam also not good at soldering
the best i could do is replace the dreamcast internal battery (which is considered a bit hard for me)
+sa97 inc I wonder if its a capacitor issue maybe? Have you inspected the SMD electrolytics? There's a chance if your laser I guess? Have you tried adjusting the spindle height to raise or lower the CD vs the laser?
+GadgetUK164 I haven't tried any of the suggestions above
I also noticed that it mostly happens when i first turn the system on
If you want
I can upload a video for you for how the disc spins when i encounter that problem
Hi, then. Can you give a hand, pls? I've got a Skeleton model Saturn, I've just changed the laser board and lens, and its working very well while the console is open. When I close everything the disc just wont spin. Opened console works, closed dont. Can you imagine why? Thanks a lot
Sounds like a bad connection somewhere?!? I would make sure the lid switch is not the problem - sometimes that kind of thing could cause the problem you've described.
I installed a Switchless region mod in my sega saturn and now I just get a black screen, disc wont spin or anything. Any idea what might cause this? I followed the instructions to a tee, the correct traces were cut, all solder joints have been double checked so not sure what could have gone wrong?
If in doubt, undo the mods and re-test without them. Perhaps you could the wrong trace or something like that? Or perhaps there's a solder bridge somewhere near the mods? It could also be something not connected up properly somewhere?
Wow - looking forward to the next bit.
Thanks! I've got a spare part on the way. As soon as that arrives I will get part 2 up! Hopefully it should be working soon!
Looks like a simple fix so far. Just hope the laser isn't shot. I gotta black Nights analogue controller for sale if your interested.
Thanks, just got a controller yesterday! There's a drive fault with this Saturn - part two coming later in the week!
Hey buddy, what 2 pin holes are you using out of the A/V connecter. I have a Saturn but no cable. I know there only a couple of quid but seeing you do that i can just make one to play a quick couple of games on. Cheers.
Top right, pin 8 is composite. Wedge the ground in between the shielding and the case around the connector.
+craig gilchrist So wait, is it one solid piece of metal connecting the two pins 8 and 11, then both leads crimped/soldered onto the metal? Or is it two single pieces, each one soldered/crimped to a lead from the composite cable?
I have a Sega Saturn board VA0 like yours and I get no video output. My TV detect a signal but black screen. The CD is spinning normally. Any idea what could be wrong ?capacitors?
My AV cable is fine as I I tested it with another console.
It could be down to bad SMD capacitors - check they aren't leaking (the Japanese ones it is more common to occur). Also measure the voltages coming out of the power supply. It might be caps on the PSU. Be careful when measuring as there are high voltages on the PSU board. Also worth checking your video cable and where it plugs into, just to rule it out.
I may have an old Saturn pad I'm not using if you want it. I got it with my import Saturn. I don't know if it even works.
Thanks!!! Got one already! Part two will be coming later in the week - It has a CD fault and I am waiting for a spare part before I upload part 2.
You wouldn't happen to know the size of the screws that hold the case together would you? I picked a Saturn up that had no case screws. Works fine though!
Hi, I am not sure at the moment but I will take some close ups later if that helps? There's also the service manual here which will likely mention exact screw sizes:-
console5.com/techwiki/images/3/39/Sega_Service_Manual_-_Sega_Saturn_%28PAL%29_-_No._013-1%2C_June%2C_1995.pdf
Looking at the service manual I think it's part 43:-
43 029-000035-0B B-TITE SCR PH BLK 3X10
Presumed the 3X10 is the size? Hard to tell, also not sure if the revision that service manual is based on is the same revision as yours (and mine).
GadgetUK164 Thank you!
My Saturn as been acting really odd with displaying the game's graphics
There are times where the game doesn't load at all, the graphics are glitchy or some graphics are missing.
you did mention around 9:00 that the 315 5688 and 315 5690 chips are for displaying the graphics. Is there a possibility to change those chips?
Yes, you could change the graphics chips, but hard to do. The SH2 processors also generate 3D graphics. Missing or corrupt graphics is most likely either a cap issue on main board or a glitchy SRAM either on main bus or perhaps on SH2 bus.
Also worth checking out the capacitors on the PSU - be careful as you can get a nasty shock from the main DC smoothing cap on there, and obviously make sure power is disconnected from mains before you take the PSU out.
8:17 I was first going to comment and say "What kind of muppet replaces a fuse with a jumper wire??", but I'm not that sure anymore that it's not factory standard. It's difficult to estimate the thickness of the jumper link from that camera distance, but such a jumper could act as a fuse given the dimensions are exactly calculated and/or tested. Or, the designers might have decided to skip the fuse to cut costs and just go for a jumper link instead. The reason I'm suspecting that it might not be an ugly user fix is that the soldering looks pretty decent, and I would suspect that someone who makes such a stupid decision as to replace a fuse with a jumper wire is probably not very skilled at soldering either. Also, I don't see any silk screen markings for the fuse. It only says "fuse", and there is no symbol for it where the fuse should go, as there are for the other components. When populating with actual components, it's common to designate each given component a certain number. So even if there were only one fuse on the board in the form of a real component, it would make more sense to call it "F1" instead of just "FUSE"... hence my suspicion the jumper link is mounted like that in factory.
Hehe, yes, I did wonder initially if someone replaced the fuse, but as you say - It looks like a wire link done at manufacture. I think they changed the design and decided not to add a fuse. The wire is pretty thick, I mentioned on the video it might take 3 amps or so to blow, but looking at the thickness I suspect it would take a lot more and I don't believe it's designed to be a fuse as it stands. It could be designed to allow isolation of that part of the board. I know if some systems (Lynx is a good example) they designed it whereby each section of the logic can be isolated from VCC by removing a single inductor or wire link.
I think I will have to agree with you there; the jumper link in this video doesn't look like a fuse at all. It's difficult to estimate the exact size from the video, but it can probably carry a lot of current. I guess it might be a problem if it couldn't since we would then have a big voltage drop across the jumper which is not good at all. But regardless of the fuse on this particular board, it's not a completely uncommon technique to use a small strand of wire to temporarily replace a blown fuse during troubleshooting of a board. Blowing up strands of wires in the case of a short on a board can be a lot cheaper than having to replace fuse after fuse until the short is finally found and repaired.
i knew earlly japanese saturns had the different psu mounted to the top of the shell but i have never seen or knew they made them in the western model, interesting.
Yes, it's very strange isn't it! I've seen quite a few pictures and videos where the PSU is mounted on the lower part of the case rather than the top part.
sega are very quirky when it comes to models and what boards were in their consoles, some unique details can be unearthed.
Yeah. My North American model 1 PSU looks like a model 2 PSU and mounts to the motherboard in the bottom (not attached to the top at all).
The only Sega Saturn to use the top mounted psu is the va0 motherboard, the very early ones. Everything was changed for the va1 where it's more familiar to what a model 1 Saturn is. And the va2 and va3 changed the cd drive from 20 pin to 21 pin, va4 and va5 are the first model 2 saturns.
man i dont see in wat points you put the av aut i dot anderstend haw
See here - gamesx.com/avpinouts/saturnav.htm You need comp video, and ground to get a composite video signal out to your TV. I just tested by feeding the wires from a composite lead into the relevant connections on the AV port there.
@@GadgetUK164 so which number have av
@@GadgetUK164 8 is video ?
@@GadgetUK164 it works thex but the lezer dos not red cd muzic
Can you please help me? The console is VA 0.8 USA. I power the console and I can set the language, but the selection box is not present. After that I can set the clock. After this I get the "saturn" white text, but the big blue saturn logo is missing. Followed by a black screen.
I can boot the pseudo saturn from the cart slot, but it just hangs when starting the cd.
I made a cart with the saturn test menu (hiddenpalace.org/Sega_Saturn_Test_Menu_v1.0f). But i just get black screen after "licensed by sega".
I removed the bios and I installed a region free one. No differences.
I replaced the working ram at IC3 and IC4 without any difference.
I replaced the working ram at IC31 and IC32 and no difference.
If the ram at IC32 is removed, the console acts the same. And yes, this ram has all the connections to IC6 ok.
I've also checked all the connections on ECABUS and ECDBUS.
The board doesn't have signs of corrosion.
I presume you ruled out the drive by swapping with one from another Saturn - just to rule it out? PSU is unlikely here, but have you measured the voltages from PSU to make sure one is not low? Assuming you've done those things and the fault is the motherboard, I would normally suggest caps on a JPN / US model - but you've checked those already. That leaves, RAM, processors, arb / custom chips. Are there any clues from anything getting hot? Looking at the only schematics I have (perhaps not the same rev as your Saturn) - I see a load of 74LS245's. I would blitz those next, swap them for new chips and see if that solves the problem. Also consider the ROM may be the issue.
Beyond that, I suspect it could be a broken trace somewhere that you've missed, or a faulty custom chip (one of the 315-blah parts, large QFP chips). The only way you could find a fault like that is by scoping the various buses and control signals, or using a logic analyzer (but that would be incredibly difficult as the Saturn is packed with hardware). Slim chance one of the processors is the issue, 68K, SH-2 etc.
@GadgetUK164 - Retro Gaming Repairs & Mods The power supply is ok. I've tested in an identical va 0.8 console (i have many motherboards and only one psu). I've read somewhere that the console perform some tests before the logo. Maybe that's why the logo is missing. Any ideas? I doubt that any custom ICs are bad.
I pm'ed you regarding Speccy 48k ram chips, did you get it? Also have you seen this, EBay item 281138097707 no, read what it does it sounds interesting
That cassette adaptor looks interesting, but I've had bad experiences with turbo loaders and these adaptors (and MP3 for that matter). Will take a look at the PM now.
I fried my japanese sega saturn with a UK power plug whats the quickest fix?
+steve5123456789 Hmmm, assuming the PSU didn't fry the motherboard, I would first swap out the PSU with a european PSU. Chances are it might work after that. I've no idea what damage may have occurred on the PSU though.
GadgetUK164
Is that safe using a euro PSU?
Yes, the PSU is modular - they output the same voltages but both take different input voltages. A Japanese Saturn PSU expects 110v to 120v. A Euro Saturn expects 220 to 240v. Both PSUs output the same voltages to the motherboard, regardless of their input voltages. Make sure you get the same model - there are 2 PSU types. Model 1 Saturn has PSU screwed into top part of case. Model 2 Saturn has PSU screwed into bottom part of the case.