Edited:6/30/07 Safe ohms setting for the laser lens pot on Duo systems?

[Platinumfungi]

I'm wondering if anyone can tell me the safe ohms range that the laser lens pot on a Duo can be set too.  I've heard with PS2s and other cd format systems that adjusting the laser's pot past a certain reading (thus making it too strong I guess) has the potential to damage the media. 

Any thoughts? 

[Mobius]

I don't know how to tell what it's set to or what it theoretically should be set to, but I found a good setting just by sheer trial and error.  It ended up being about a 90-degree counter-clockwise turn from the position it came in. (I bought it off of electronix.com.)  All in all, I think it's a little more than 180-degrees from the furthest clockwise position possible.  Sorry I don't have a better way to describe this.

It took a few nudges to get it just right, but that was just to get one particularly finnicky game working consistently (import version of Golden Axe).  Lords of Thunder was pretty finnicky, too, but that started working a little sooner than Golden Axe.

It might also be worth mentioning that when I first put the new laser in, everything worked perfectly right off the bat.  Then a couple weeks later, it would barely read anything, let alone CD audio.  That's when I started messing with the potentiometer.  So I wonder if it takes some time to "break in"?

[termis]

I think trial and error really is your best best.  I haven't had problems with the replacement HOP3 eye from electronix since I've put it in (about 8 months ago), and I never even bothered fudging with the meter.

I have played around with the meter for the Saturn laser eye, and I just move it by 10 degree increments each way until it starts read originals, then CD-Rs, etc...

[Platinumfungi]

Thanks for the input you two.  I'm hoping to find out the exact rating as this would really help speed up repairing/troubleshooting.  If I have to I'll keep adjusting, but it seems that a physical number would be a handy bit of info for the community here.

[nat]

I'm having problems with a non-Duo CD unit, it's a CD-ROM^2 hooked up to my SuperGrafx.

On one game, and one game only (Mad Stalker/Full Metal Force) the CD music will stop playing like a minute into each level. The sound effects continue as normal. after I beat a level and start the next (which in turn has a new, unique music track) the music will start again but only last for another minute then stops.

I have approximately 1,243,364 other CD games and each and every one works flawlessly on the same system.

If I play the same game in my TurboGrafx-CD I don't have this problem. I'm guessing the CD-ROM^2 laser on the SuperGrafx is out of adjustment by an incredibly small amount and MS is the only game that is affected.

Can the laser be adjusted on these older CD systems the same way as a Duo or am I S.O.L.?

[Mobius]

Virtually all CD drives can be adjusted in this way (or at least, every drive I've ever wanted to adjust).  Open it up and look for what looks like a plastic screw on the CD assembly.  That'll be how you adjust potentiometer.

[Platinumfungi]

Nat - Since it's only one game my normal guess would be that it's just scratched. However since it works fine in your TGCD then I'm not sure. I've heard of this same type of problem on other systems too (snes among others) where a game will work on one system but not on another and both systems seem to work fine otherwise. 

All cd laser len assemblies should have a pot on them. Every one that I've ever looked at did.

I'd be very careful with adjusting your Supergrafx CDROM2 setup though. I'm not sure of the model of laser lens unit in them so finding a replacement (if need be) might be difficult.  The Duo units all use the HOP - M3 to my knowledge, but the CD-ROM add on units don't. Also be sure to mark where the pot is before you start adjusting so you can turn it back to the exact point if need be.

[nat]

Nat - Since it's only one game my normal guess would be that it's just scratched. However since it works fine in your TGCD then I'm not sure.

No scratches. Not even the "hold in the right light" kind of scratches. The game was brand new when I got it and I haven't played it much. Of course, that was the first thing I looked for (fingerprints, dirt, scratches, etc).

I'd be very careful with adjusting your Supergrafx CDROM2 setup though. I'm not sure of the model of laser lens unit in them so finding a replacement (if need be) might be difficult.  The Duo units all use the HOP - M3 to my knowledge, but the CD-ROM add on units don't. Also be sure to mark where the pot is before you start adjusting so you can turn it back to the exact point if need be.

That's why I asked about it first. I'm not real crazy about opening it up and trying it without knowing what I'm getting into.

[SignOfZeta]

At 765 the PC Engine Duo works quite well but still occasionally has issues with Lords of Thunder's audio.

Where in the world are you getting these numbers from? Are these mΩ readings or something?

Anyway, there is no set perfect value. If there were, the things never would have been adjustable in the first place. You are just supposed to screw around with them until they work.

[Platinumfungi]

At 765 the PC Engine Duo works quite well but still occasionally has issues with Lords of Thunder's audio.

Where in the world are you getting these numbers from? Are these mΩ readings or something?

Anyway, there is no set perfect value. If there were, the things never would have been adjustable in the first place. You are just supposed to screw around with them until they work.

I'm measuring the resistance in ohms with a multimeter. I was assuming that there was a sweet spot for the laser's voltage. I know that with other systems people have discussed the ohms ratings and come up with some solid numbers. Perhaps that's only when you deal with backup media? 

Since originally posting I've tweaked them a lot and haven't really found any setting to be more effective then another (after replacing caps and making sure I had a working laser that is) so I have removed all measurements for now.

Thanks for the input everyone