Sega Saturn Model 2 - No Video + Disc Wont Spin

[alcatraz68]

I have been directed to this forum in the hopes of finding someone who can diagnose a problem with my Sega Saturn.

I installed a Switchless Region Mod in my Model 2 console but now I'm no longer getting any video from the system, if I connect via composite the pictures rolls and flickers, and if I connect via RGB SCART I get a static black image, and either way if a disc is inserted it doesn't spin.

I am certain the region mod was installed correctly, I cut the necessary traces and checked the points with my multimeter, and I have double checked all my solder joints to make sure they're in the correct places and are solid.

When I power on the console the switchless mod seems to be working, if I hold down the reset button it cycles through the different colours as it should do, but nothing happens on screen so something must be wrong on the board, but I really don't know where to start looking or what I need to look for?

(I should also mention that I tried to 'uninstall' the mod by removing the mod and reconnecting the cut points with solder, but the console would not work at all when I did this, the led light just slowly flickered on and off and there was a clicking sound when it did).

[NFG]

It's possibly coincidence, that something else failed when you did this mod.  These are old consoles, after all.  But chances are more likely that you've shorted something out accidentally. 

When you say you checked the work with your multimeter, were you only checking for shorts?  I might recommend you also check for stray voltages, see exactly what's going where.  Remember that you're working with Vcc and GND here, and if either the mod guide you used or your thinking were muddled at all, you might end up connecting one to the other.  And a weak connection between the two will cause trouble for sure.

I have modded dozens of systems and never had this happen, and I struggle to imagine how these symptoms can result from what you've done, but a bad connection might be responsible, I guess...

Posting some (clear!) pics might be helpful too.

[alcatraz68]

Thank you for your quick response.

I only tested the points where I cut the traces to make sure there was no longer a connection between the two points. I get a zero reading on the multimeter for all of them. How exactly do I check for stray voltage? I've only ever used my multimeter to check for resistance.

I took some pictures and while doing so I made SOME progress. I decided to make sure all the flux was cleaned off the points i'd soldered, and once i'd done this the system actually booted! It got to the home screen, I was able to switch between regions, it was working perfectly. Then when I tried to load a game it suddenly went off and the black screen came back, and now it wont work again... the screen no longer rolls when connected via composite but unfortunately there is still an issue somewhere.

I have attached the pictures I took prior to cleaning the flux.

[alcatraz68]

More pics

[alcatraz68]

More pics

[alcatraz68]

Another update. The problem seems to be caused by the reset button, it's as if the button is being pressed which forces the console to stay on a black screen, but sometimes i'll see the lights cycling though by themselves. Sometimes the console will boot fine but it will change region by itself.

I have measured the resistance between the button and reset points on the controller pcb and I get a 0 reading, but when the console is powered on I get a voltage reading between the 2 points, is this correct?