Saturn model 1 finicky about reading discs

A short while ago I got two non-working NTSC-U Saturns for cheap. I got the model 2 working perfectly now and outside of missing a few non-essential parts, I'm almost done with the model 1.

I've got the model 1 reading discs about a third of the time and I know the issue isn't with the lens since it works 100% of the time when I use it in the model 2. My best guess would be to mess with the four pots on the drive board but I wouldn't know what which pot controls on the drive. Any ideas on how I can get it reading discs consistently?

 

Those pots on the board do not control anything with the laser, I'm pretty sure. As a hail Mary at this point, try playing around with the intensity with a multimeter. Note that this may or may not kill it, and any "professional" would be yelling at me right now. But first, measure the stock values of the pot and write it down. Next, try going up and down in resistance maybe 10 values at a time. Then keep installing and keep trying. Eventually, something will work. Or just fry it if you go too extreme.

 

The pots on the drive board adjust the focus and tracking servos - the most critical adjustments are the ones to the focus servo - unfortunately, they are also the ones that are most difficult to carry out without access to the test disc, because there are two different focus offset adjustments (one static and one dynamic). Setting them by trail and error is very frustrating - if you have a meter and a scope, adjusting the static offset for 0V at the test point and then adjusting the dynamic offset for maximum signal at the eye signal test point should be pretty close.

Having said that, if possible you should try to get a pickup that's been verified to work in a model 1 drive for testing - the newer drives have better read electronics and will tolerate a lower signal than the old ones could - so although it's safe to say that a pickup that will work in a model 1 drive will work in a model 2 the converse is not necessarily true.

In this case, adjusting the laser power might well fix it, although - as supersega mentioned - it does run the risk of blowing up the laser diode if you push it too far.

 

Went with the route that I'd be the least likely to screw up and switched out the old pickup unit with one from a for parts X'Eye. Sure enough, the model 1 is reading discs consistently now.

 

You killed an X'Eye to get a Saturn to work??? Isn't the X'Eye worth 3 times what the Saturn does?

 

What can I say, I have messed up priorities. The X'Eye I gutted for the pickup has numerous problems and fixing it is near the bottom of my list of priorities since I already own a fully working unit.

 

I would have sold it. A broken X'Eye is still worth more than a fully working / tested Saturn.