Sega Saturn Mods / Fixes
Hey everyone, It is early days for this page. I knew i would end up with one of these. But i have only just got one. So this page is defiantly "BETA" till i get my head more into how it all works.
Fixing "Can not read CDs"
Well being my first unit.. and hearing that this was a common fault... I thought it a good place to start. Mine has begun to develop the fault. So i have had to start development on a fix sooner than expected.
From reading up on CD lens theory (been a while since i have had to do stuff on it). There are to settings that are useful to change.
BIAS and GAIN,
BIAS, This control sets the default DC voltage flowing through the servo coils in the laser that move the laser lens up and down. GAIN, This control sets the voltage that is added or subtracted from the bias voltage by the servo circuits for a given fluctuation.
So with this in mine i opened up my Saturn to find if i could see if these were adjustable.
Looking at the CD drive PCB i found a few adjustable resistor or pots. Labels EF, FG and TG. I thought this would be a good place to start. Results of measuring voltage on the output of these Pots (the middle pin is the output voltage, or the "TAG" at the top that shows the position is also a good probing point)
CD IN NO CD MOD DONE / NO CD
FG 2.53 V 2.51 V 2.52 V
TG 2.53 V 2.51 V
EF 2.30 V 2.55 V
After measuring this.. I decided that FG might be Focus Gain, and TG might be Tracking Gain.
So i decided to increase the No CD Voltage of the FG and see what happens. I turned the pot CLOCK WISE. only about 5 Degrease (you can adjust latter when measuring the voltage again)
I presumed that this would increase the focus, due to the age of the laser, and in theory, enable the drive to work again.
Well it is early days yet.. but it will now read a CD that it would not before. So maybe I'm on the right track. Time will tell :-)
Well have just finished running the system for 6 Hours straight. Did not skip a beat! Looks like this is a mod to try if your Saturn stops reading disks.
