PC Engine Duo laser locking up to the right

[HoocasLenkels]

Hello all

I've recently run into a problem with my Duo. Keith Courage repaired it months ago, and everything works fine (Thanks again!) That is, until I started playing more CD games with it.

Before, I only had a few CD games, and didn't use it all that much. Now that I started getting more CD games, the laser assembly will jam or lock up all the way on the right side, forcing me to open up the console and reset it by hand. It's getting incredibly frustrating at this point. It will only do that on certain games though.

Keep in mind, this unit has been recapped, and showed no issues, as far as I could tell, beforehand. I tried cleaning and greasing the spokes of the gears, but still the same issue. Lens is also very clean.

The games it locks up on are:

4-in-1 Gate of Thunder
Dynastic Hero
Hellfire S (locks up after beating the first level, WTF?)
Terraforming
Super Air Zonk

Those are the only ones, so far, that made it lock up. It won't even read the disks, the screen goes black, and then the cd stops spinning and when I open it up, the laser is locked in place on the far right side.

What could be causing this? Is the laser dying? Do I need to tune the trimmer caps? Why is it only happening on some games? I can play through Lords of Thunder or Prince of Persia no problem, but if I even put super Air Zonk in, NOPE.

Any and all help is appreciated. Thank you all in advance.

[thesteve]

its caused by a seek error
can be a bad burn or scratched disk most often
could be adjustment as well, but would effect more games

[HoocasLenkels]

I have the system sitting open in front of me now.

I can get dynastic hero to play, but only if I wiggle the spur on the motor when it locks up at the far right, if I wiggle it and let it go back, it will play the game.

Bad burn maybe like you said?

[Keith Courage]

yes, this is a symptom of using cdr discs. might be a bad burn but also could just mean that your system hates cdrs.

I've seen some systems that can have this issue remedied by some slight potentiometer adjustment but others where adjust makes no difference.

[thesteve]

ive seen some roms that lock constantly on some systems (no fix) but recover on others
NEC knew about the issue as they added a clutch to the big gear on the DUO-RX to prevent the lock-up

[HailingTheThings]

If you're playing back ups, please use 74min CD-Rs. Burn no faster than 4x if you can help it.

http://www.amazon.com/MAM-A-Mitsui-DIGITAL-AUDIO-74-Minute-Cakebox/dp/B00J8OMXHW/ref=sr_1_1?ie=UTF8&qid=1413874916&sr=8-1&keywords=mitsui+gold+74

http://www.ebay.com/itm/50-Pak-GOLD-Gold-Inkjet-DIGITAL-AUDIO-74-Minute-CD-Rs-by-Mitsui-MAM-A-/390803570326?pt=US_CD_DVD_Blu_ray_Discs&hash=item5afdb53e96

[NightWolve]

Woah, that's a helluva price range for those CD-Rs of yours there, Hailing! You don't need to go that far! Heh.

If you are using CD-Rs though, yeah, always burn them at the slowest speed allowable as that actually makes a difference with the burn marks on the surface. The laser in a computer's optical drive (CD/DVD) is modern and will always work no matter what speed was used on recordable media, but early generation lasers on retro consoles will not always perform well with high speed burns.

http://www.amazon.com/MAM-A-Mitsui-DIGITAL-AUDIO-74-Minute-Cakebox/dp/B00J8OMXHW/

Interesting thing, they state that the manufacturer is nice enough to pay a generic license fee to the music industry for manufacturing these discs.

Quote: "These consumer audio-only CD-R discs meet the standards of the Audio Home Recording Act (AHRA) of 1992, which requires a royalty to be paid by the disc manufacturer to the music industry. These CD-R's support the Serial Copy Management System"

Never knew such an arrangement was in place to throw the music industry some kind of bone for pirating. Heh. But, if that means a 50 pack of CD-Rs must be priced around $100, to hell with that! I know, that sort of pricing is mostly cause of the supposed quality, so just playing, but damn! ;) Too rich for my blood!

[HailingTheThings]

Woah, that's a helluva price range for those CD-Rs of yours there, Hailing! You don't need to go that far! Heh.

If you are using CD-Rs though, yeah, always burn them at the slowest speed allowable as that actually makes a difference with the burn marks on the surface. The laser in a computer's optical drive (CD/DVD) is modern and will always work no matter what speed was used on recordable media, but early generation lasers on retro consoles will not always perform well with high speed burns.

http://www.amazon.com/MAM-A-Mitsui-DIGITAL-AUDIO-74-Minute-Cakebox/dp/B00J8OMXHW/

Interesting thing, they state that the manufacturer is nice enough to pay a generic license fee to the music industry for manufacturing these discs.

Quote: "These consumer audio-only CD-R discs meet the standards of the Audio Home Recording Act (AHRA) of 1992, which requires a royalty to be paid by the disc manufacturer to the music industry. These CD-R's support the Serial Copy Management System"

Never knew such an arrangement was in place to throw the music industry some kind of bone for pirating. Heh. But, if that means a 50 pack of CD-Rs must be priced around $100, to hell with that! I know, that sort of pricing is mostly cause of the supposed quality, so just playing, but damn! ;) Too rich for my blood!

I know, a little pricey, but they are quality discs. Pretty much the kind of CD used when burning an audio master disc that is driven in an armored car to the pressing plant by the big wigs. lol

I've never bought them in a spindle. Whenever I run low I usually buy a 10 pack with cases when I can get 'em cheap. Who doesn't need more CD cases? :3

[HoocasLenkels]

Thank you everyone for all the help!

I checked out the sticky thread on adjusting the laser, and hooked up the duo to my scope and multimeter today and started tweaking everything.

I've gotten it to read all my real cd based games perfectly, and most of my burns as well. Still a few giving me trouble. The ones that are giving me problems are all much larger games, so that may be the culprit in and of itself like you gentlemen had said. I'm not too worried about it reading them all anyway. Gives me me an excuse to buy more games now.

I like to try out sme of the more expensive games before I commit to buying them usually, to see if they're worth the entrance fee so to speak (as as sacriligious as that sounds). It's how I ended up with a lot of my more expensive titles! Try before you buy. 


Long story short, I'm just worried that it will have trouble reading actual games of a larger size down the line when I get them. Should I be worried? Or is this only a usual symptom for cd-r burns? Thanks again!

[NightWolve]

Ah, a pro, you tweaked the laser-related pots with a scope and got most discs working! Congrats!

Since you got that out of the way, the other simple tweak for the laser is to clean out the 20 year old lithium grease from the slider pole and apply fresh grease. Regaining agility will help prevent the cutoff problem where an audio track is playing, but it suddenly skips (read failure), and then cut offs, no further audio is played until a scene change in the game triggers the seeking for the same or another track, etc.