Turbo Duo on it's last legs?

[GUTS]

So I was trying to play a CDR of Exile II (yeah I know I'm evil, but I can't find it even on ebay dammit) and it wouldn't boot on my Duo.  I burn about 6 different discs and one of them finally boots, but locks up.  So I think, hey I remember the old playstations used to work better upside down, and bang that works, all the discs boot up fine.

So here's the problem, my originals are starting to have problems now. For example, the music on Dungeon Explorer II and Dracula X is cutting out once in a while.  They play fine, but the music thing is annoying as hell.  My question is, does anybody know if there's a way to adjust the laser like on a Playstation?  Is it bad to play CDRs?  I heard from one guy that they wear the eye out faster, but then another guy who knows what he's talking about said that was just an old wife's tale.

[DragonmasterDan]

The earlier Duos will barely play CDRs at all. I know mine can boot one or two. but the rest of my backups have problems and even when they do run redbook audio cuts out and it takes forever to load. Did you try an actual glass mastered CD those always run fine for me? As far as preventitive maintance goes don't use CDRs anymore (they seem to overwork the laser) and if the problem is REALLY bad with skipping I would recommend GENTLY use a Q-tip and carefully wipe the lens. Do not press to hard.

My experience is not to trust backups for anything but use on emulators. TurboDuos were not meant to read CDRs. There was that retrogames guy who was putting new lasers in Duos but he appears to be out of business.

[GUTS]

Ok, sounds like good advice, I wasn't sure about CDRs wearing it out faster, but it's better to err on the side of caution in this case.  I looked at the bottoms of the two games that the music was cutting out on and they have a few tiny scratches, so that might be whats doing it.  I remember stevek666 said his had problems with even tiny scratches, so mine is probably the same.  I have a polisher at work so I'll try that.

Now I just need to find a US Exile II, DAMN that game is tough to find!

[TurboHuC6280]

I'm not of the belief that CDRs actually "wear the system out" faster.  I feel it's an old wive's tale.  It's fair to use your own judgement though.  Everyone does things their own way.

[pixeljunkie]

I'm not of the belief that CDRs actually "wear the system out" faster.  I feel it's an old wive's tale.  It's fair tou use your own judgement though.  Everyone does things their own way.

Ditto on that, I rarely use CD-Rs on my Duo because it just didn't like them. Sometimes they worked, other times not. I've read MANY stories about U.S. Duo's not consistently playing back CD-Rs. PCE duos apparently have no probs though.

[GUTS]

Actually that's what I have, a PCE Duo modded to play US/jap hucards.  At least I think it's a PCE Duo, the writing on the bottom is all in japanese and it says PC Engine Duo on it, although I can't be sure since sometimes US versions of hardware still have the jap writing and it's modded so I have no idea which region is the original one.

[pixeljunkie]

Actually that's what I have, a PCE Duo modded to play US/jap hucards.  At least I think it's a PCE Duo, the writing on the bottom is all in japanese and it says PC Engine Duo on it, although I can't be sure since sometimes US versions of hardware still have the jap writing and it's modded so I have no idea which region is the original one.

Yeah, the model 1 Duo's  all seem to have that issue. I meant to say Duo-R or RX's do not. Although I have a Dracula X burn that always worked fine on mine. But a burn of Spriggan Mark 2 which only worked sometimes...weird.

[TurboHuC6280]

I'm not of the belief that CDRs actually "wear the system out" faster.  I feel it's an old wive's tale.  It's fair tou use your own judgement though.  Everyone does things their own way.

Ditto on that, I rarely use CD-Rs on my Duo because it just didn't like them. Sometimes they worked, other times not. I've read MANY stories about U.S. Duo's not consistently playing back CD-Rs. PCE duos apparently have no probs though.

Yeah.  I just prefer to buy the real things.  Sounds like you do too.  

[pixeljunkie]

I'm not of the belief that CDRs actually "wear the system out" faster.  I feel it's an old wive's tale.  It's fair tou use your own judgement though.  Everyone does things their own way.

Ditto on that, I rarely use CD-Rs on my Duo because it just didn't like them. Sometimes they worked, other times not. I've read MANY stories about U.S. Duo's not consistently playing back CD-Rs. PCE duos apparently have no probs though.

Yeah.  I just prefer to buy the real things.  Sounds like you do too.  

EXACTLY

[DragonmasterDan]

I'm not of the belief that CDRs actually "wear the system out" faster. I feel it's an old wive's tale. It's fair to use your own judgement though. Everyone does things their own way.

It's not just an old wives tale and let me explain why, CDRs quite frankly aren't as easily readable as glass mastered CDs go. The reason being the dyes on a CDR don't typically make as clear of a marking as does the 0s and 1s on a glass mastered disc.

Case in point, just a few years ago the community at http://www.dragons-lair-project.com/ wanted to make reprint laserdiscs of Dragons Lair for use in old arcade machines. As many of you might be aware Laserdiscs (and early CDs) suffered from something called LaserRot which was when moisture and other oddities would get in between the lining of the disc and start to bubble up and grow (in some cases mold) or warp the disc to a point of utter uselessness. People wanted to make new Dragons Lair discs (since rot resistant materials used for making discs, glueing and pressing them now exist that didn't back then) that would be playable on their old arcade machines for years and years to come. After acquiring the rights from the Dragon's Lair LLC they started doing some substancial looking around the community discovered that lots of places could do the laserdisc equivilent of a CDR (making a laserdisc with burnable discs). However because of the age of the LD players in use in most Dragon's Lair machines the discs either skipped, or didn't work alltogether on such old lasers. Newer better lasers (aimed at reading around scratches, scuffmarks and other problems with discs) had no trouble reading the burned LDs. But the result was that the community at Dragons Lair Project was forced to turn to imation in order to get a glass master and glass mastered discs made. The same goes with CDs, the markings aren't as clear on copied media which is why they have trouble reading them. On newer CD-ROMs it's not any sort of a problem since the lasers even on the cheapest CD drives (found in 9.99 imitation discmen) are several generations of technology ahead of the Duos drive and are far better at reading CDR media than are the lasers from the very early 90s found in the TurboDuo. The reason the Duo can have problems from reading CDRs is because focusing in on spots on a far harder to read media forces the duos laser to work too hard and wears it down. It's kind of like a near sighted person constantly squinting to read street signs. Simply put the drive is a mechnical device and the extra work causes wear and tear on the device.

Ditto on that, I rarely use CD-Rs on my Duo because it just didn't like them. Sometimes they worked, other times not. I've read MANY stories about U.S. Duo's not consistently playing back CD-Rs. PCE duos apparently have no probs though.

It depends on the age, the Duos manufactured later in the systems lifespan likely have a different revision laser and drive in place that's better able to read CDRs. That's my guess. I know personally my US October 1992 manufactured Duo reads glass mastered discs flawlessly but chokes and stutters on CDRs. A good way to test if yours has problems is take a factory made CD of music you own and put it in your duo, it should work fine. Then make a backup of it and play it in your Duo. In my case the Duo will choke even when burned at 1X on Verbatim discs. Simply put the problem is that the Duo wasn't made for CDRs.

[PCEngineHell]

On the talk of "laserrot".I collect laserdisc and have a extensive libary.
1:Laserrot is caused by the glue chemicals not being mixed right,dust trapped inbetween the plastic and glue,and the disc layers not being sealed real well.
What caused cds to oxidize back in the 80ies is not what caused LDs to rot.
The cds rotted because they used cheap aluminum layer crap that just couldnt last with age.
The rot was visible on the cds.
On LDs,unless its maybe a DiscoVision disc,from the 70ies,which were about all made in crappy plants with no clean room standards,you would not see the oxidization on the reflective layers,except of rone instance,3M,which changed to Imation,did a really bad batch at one time,which had visible rot.But to be noted,they did not use the same method to produce LDs that Pioneer used,and they worked their problem out farely fast.Most Sony LDs rot,they had the poorest quality.
In the standard manufacture process of a LD,after the nickle plate is made of side one lets say,and side 2 of a ld,they would use it to make the plastic sides,and pour on the reflective layers on those plastics,and then glue them together.Imbalances in the glue used,trapped air,and very lite and extremely hard to see dust could sometimes be trapped inbetween during the glue process,sometimes even before the reflective layer is poured on the plastic.
Anyway,this could cause the reflective layer to slightly change its reflective qualities,causing colored snow dots to appear in the picture image of the movie.I dont count line dropouts because scratchs,even light ones can cause those.It would get worse over time,sometimes getting so bad that the disc would play,or it would stop,and the disc would get no worse in picture quality.Kinda imagine it as being a curing process.If a LD you have plays fine now,it will probably always play fine.Most all disc that are going to rot to death have already,and any that have litle rot shouldnt get any worse if taken care of and stored well.Note that the change in the reflective layer was pretty much on the microscoptic level,and couldnt be seen by the human eye.
Also to note,really expensive LD players,Sonys best and Pioneers best Elite series,and the X-9,have such good lasers that even a terrible rotted Sony Ld like Lost Highway will play with no problems what so ever,espically on a X-9,with no colored snow dots or anything.Yet you can take this same disc,play it on any typical budget LD players and it will be a horrible experience for you.Basically thi sis because of the laser used,and comb filters.Keep all this info in mind if you ever decide to get into LD collecting.Also,I have the first Salmander anime on ld imported,its one of my oldest lds I own,besides the first release of Evil Dead 2,and it plays perfect,with no problems,as do most my LDs I own.You just have to be picky about what you get,and check the manufacture of the disc before you buy it,check the mint marks on the lds,it states who made it.Alot of stuff on LD,like the sci-fi Hardware,is not on DVD,and probably never will be.Lds have better sound the DVD most of the time,and the picture quality is extremely nice over all.

[DragonmasterDan]

On the talk of "laserrot".I collect laserdisc and have a extensive libary.
1:Laserrot is caused by the glue chemicals not being mixed right,dust trapped inbetween the plastic and glue,and the disc layers not being sealed real well.
What caused cds to oxidize back in the 80ies is not what caused LDs to rot.
The cds rotted because they used cheap aluminum layer crap that just couldnt last with age.
The rot was visible on the cds.
On LDs,unless its maybe a DiscoVision disc,from the 70ies,which were about all made in crappy plants with no clean room standards,you would not see the oxidization on the reflective layers,except of rone instance,3M,which changed to Imation,did a really bad batch at one time,which had visible rot.But to be noted,they did not use the same method to produce LDs that Pioneer used,and they worked their problem out farely fast.Most Sony LDs rot,they had the poorest quality.
In the standard manufacture process of a LD,after the nickle plate is made of side one lets say,and side 2 of a ld,they would use it to make the plastic sides,and pour on the reflective layers on those plastics,and then glue them together.Imbalances in the glue used,trapped air,and very lite and extremely hard to see dust could sometimes be trapped inbetween during the glue process,sometimes even before the reflective layer is poured on the plastic.
Anyway,this could cause the reflective layer to slightly change its reflective qualities,causing colored snow dots to appear in the picture image of the movie.I dont count line dropouts because scratchs,even light ones can cause those.It would get worse over time,sometimes getting so bad that the disc would play,or it would stop,and the disc would get no worse in picture quality.Kinda imagine it as being a curing process.If a LD you have plays fine now,it will probably always play fine.Most all disc that are going to rot to death have already,and any that have litle rot shouldnt get any worse if taken care of and stored well.Note that the change in the reflective layer was pretty much on the microscoptic level,and couldnt be seen by the human eye.
Also to note,really expensive LD players,Sonys best and Pioneers best Elite series,and the X-9,have such good lasers that even a terrible rotted Sony Ld like Lost Highway will play with no problems what so ever,espically on a X-9,with no colored snow dots or anything.Yet you can take this same disc,play it on any typical budget LD players and it will be a horrible experience for you.Basically thi sis because of the laser used,and comb filters.Keep all this info in mind if you ever decide to get into LD collecting.Also,I have the first Salmander anime on ld imported,its one of my oldest lds I own,besides the first release of Evil Dead 2,and it plays perfect,with no problems,as do most my LDs I own.You just have to be picky about what you get,and check the manufacture of the disc before you buy it,check the mint marks on the lds,it states who made it.Alot of stuff on LD,like the sci-fi Hardware,is not on DVD,and probably never will be.Lds have better sound the DVD most of the time,and the picture quality is extremely nice over all.

I collect LDs as well (in fact the reason I told this story and am so intimately familiar with the details was  that I bought one of the new Dragon's Lair discs and I own one of the 1983 originals and spent a fair amount of time around that DLP community over the past 6 or so years). In any event I gave a very short explanation of laser rot since my explanation was more about the difference in quality between glass mastered and burned optical media rather than about laser rot. I am quite aware of the reasons it occurs (and how it is different for CDs and DVDs for that matter since they don't typically have two sides) but  for the purposes of my explanation I just wanted to be brief and explain that there was a high demand for newly pressed Dragon's Lair discs.

As far as LDs go among my rarest are Song of the South CLV and then a bunch of game discs. I have a few discs that rotted myself unfortunately, thankfully I've over the years replaced most of those movies with DVDs. Some movies are just irreplacable though, thankfully most of those are in good shape. I have the THX original Star Wars discs (CLV) and the criterion Close Encounters disc with the ORIGINAL non-special edition cut. It seems unlikely that any of those movies will be released in another format legitimately any time in the immediate future. I don't have an AC3 capable LD player (I have three players but only one is ever used at this point) so to me the sound difference is minimal, but I still do love the format in any case.

[esteban]

Well, I know you folks are too scared to come out of the closet, but I will.  I use my LD for karaoke, primarilly.  Other than that, I have a small library of stuff, mostly music videos (i.e. david bowie) and crappy movies that I bought when stores were getting rid of them.  I mean crappy action films starring Mario Van Peebles and Christopher Lambert.

But karaoke, that's really where's it's at.  To be honest, my friends are the ones who want to do it all the time.  It's fun though.  I sing "Jump" (Pointer Sisters!) to my daughter, then she makes a few squeaks into the microphone and throws the mic on the ground.

By the way, have any of you folks seen the Pointer Sisters' videos during their 80's heyday?  FRIGGIN' INSANE!  Seriously, it's totally entertaining.  Amazingly entertaining.  Definitely go to your local $0.99 rental shop and look for this.

[TurboHuC6280]

I'm still not conviced.  It is certainly true that the motor in the drive can wear out if it's having to compensate for lack of reflectivity, but it's not doing any extra work if the disk is good and was burned at a reasonable speed in the first place.  The drive either reads the data, or it doesn't.  If it's not reading it, then you already have a problematic drive in the first place, in which it will *of course* wear out faster because it's trying to read the same point over and over again on each disc revolution.

It either reads it, or does not.  If it's reading it on the first pass, then it is functioning exactly the same as it would a standard glass-master CDROM.  In fact, it's very likely that you can even burn a CDR that will be read more accurately than the original, provided you have a reader on your PC that is better at reading than the CDROM2 unit, and you have some good DOA software that will allow you to burn a better copy (I've done this with some drives and disks before).

The only mechnical device in most CDROM drives (aside from the spindle motor) is the tracking motor that moves the laser up and down the radius of the disc.  There is no "squinting" involved in the way the laser reflects the highs and lows back the the opto-electronic receptor pickup.  Highs and lows are bumps and lands, and when the laser aims at a "bump", the direction of laser reflectivity is aimed differently at the receptor, and the receptor's circuitry notes the changes.

The exception might be in dual-layer devices (DVD players, PS2s, Gamecubes, etc.) where focus must be adjusted to pass through the semi-transparent outer layer, so that the laser aims towards the inner layer.

In standard CDROM drives, the failure point is the typically in the tracking motor or an improperly calibrated spindle motor - not the laser or opto-electronic pickup.  Most reports I've read (by engineers) indicate that less than 1/10 of optical drive failures are related to the laser and opto-electronic  parts of the drive.  These are photodiodes, and don't typically fail.

[DragonmasterDan]

It either reads it, or does not.  If it's reading it on the first pass, then it is functioning exactly the same as it would a standard glass-master CDROM.  .

In my experience with using CDRs both music and games on my Duo it reads it (for example boots the game) then redbook audio cuts out and it starts to freeze or the sound quits playing or gets choppy. The same goes with playing music CDs in CDR format, it starts to get choppy then cut out. So it half reads, it reads it for a while, has trouble, seeks, then reads it again on a second pass (or if it can't read it the drive just stops). And that's what wears down the motor.

[TurboHuC6280]

It either reads it, or does not.  If it's reading it on the first pass, then it is functioning exactly the same as it would a standard glass-master CDROM.  .

In my experience with using CDRs both music and games on my Duo it reads it (for example boots the game) then redbook audio cuts out and it starts to freeze or the sound quits playing or gets choppy. The same goes with playing music CDs in CDR format, it starts to get choppy then cut out. So it half reads, it reads it for a while, has trouble, seeks, then reads it again on a second pass (or if it can't read it the drive just stops). And that's what wears down the motor.

Sounds like a failing bad motor, failing gears, or it needs to be greased with some silicone.  The rails on those things get warm, and wear over time.  Often, the drive mechanisms are plastic, but I've never seen the inside of a Duo drive.  This was a common problem in Playstations and a lot of other optical drives.  Later, they switched to a smooth alloy so that it didn't wear against the rails.  Your drive rails could be offset just enough that it causes these problems with certain discs.

The audio portion of discs do not use error any sort of error correction.  It's just a raw bitstream of data that streams off of the disc and plays back at a rate of 22 kHz per channel.  Data portions of the disc use error correction and, additionally, the programs are designed to continue to try to read the data until it's finished loading.  The software has no way of telling whether or not the audio is being properly read though.  It just plays what it reflects back to the opto-electronic pickup in a raw stream, and doesn't verify whether or not it is correct.

You are correct that a CDR is "less perfect" by nature of the dyes, than a pressed CDROM, but the fact that it is not reading properly indicates a likely failure in the drive itself that has already manifested itself, and your drive's tolerance for any disc that's less than perfect is pretty much nil.

[DragonmasterDan]

You are correct that a CDR is "less perfect" by nature of the dyes, than a pressed CDROM, but the fact that it is not reading properly indicates a likely failure in the drive itself that has already manifested itself, and your drive's tolerance for any disc that's less than perfect is pretty much nil.

That's fascinating. I have used many scuffed and scratched glass mastered CDs that are far from perfect and they work without a hitch on my Duo. The problem is exclusive to CDRs wheteher they be old ones I've had sitting around to Verbatim discs burned at 1X with cdrecord in RAW mode. and I'm far from the only person to experience this, just from looking through archives of the Turbo list many other people have noticed this about their Duos. The problem is due to the nature of the technology in the old CD-ROM drives of the Turbo Duo. Reasons like this are why the retrogames guy who used to do Duo repairs advertised "Better CDR compatibility" on the newer drives he put in, since lots of people had trouble playing CDRs on their Duos. Take a look. http://www.geocities.com/turbogaming/

[TurboHuC6280]

You are correct that a CDR is "less perfect" by nature of the dyes, than a pressed CDROM, but the fact that it is not reading properly indicates a likely failure in the drive itself that has already manifested itself, and your drive's tolerance for any disc that's less than perfect is pretty much nil.

That's fascinating. I have used many scuffed and scratched glass mastered CDs that are far from perfect and they work without a hitch on my Duo. The problem is exclusive to CDRs wheteher they be old ones I've had sitting around to Verbatim discs burned at 1X with cdrecord in RAW mode. and I'm far from the only person to experience this, just from looking through archives of the Turbo list many other people have noticed this about their Duos. The problem is due to the nature of the technology in the old CD-ROM drives of the Turbo Duo. Reasons like this are why the retrogames guy who used to do Duo repairs advertised "Better CDR compatibility" on the newer drives he put in, since lots of people had trouble playing CDRs on their Duos. Take a look. http://www.geocities.com/turbogaming/

My CDROM2 drive addon is probably much older than most of the Duos (pushing 15 or so), and it has no problems at all.  I'm just saying that it's probably not due to the nature of the technology at the time, because the older drives are fine.  Most people have no problems with their Duos as well.  It's just failing units that are typically problematic.  Duos were released later than the CDROM addon, so its indicative of potentially poor design, by comparison, if more Duo systems have problems than "briefcase" CDROM systems (as most of us have probably read).

[D-Lite]

Wow, lots of stuff since the last time I logged in here and a discussion near and dear to my heart.

Well, as someone that has modded about 50 Duo systems now, I have seen a lot of guts of these things and lots of problems with them too.  Far and away the biggest issue is red book audio.  I currently have about 5 Duo systems that have some degree of that issue with them.  And the issue is obviously in some way related to the technology of the drive, which was in fact first generation in terms of CDs in video gaming consoles.  

Now, the reason for the sound issue to me is the biggest problem to tackle and undoubtedly the one most people are dying to have fixed.  And the problem is definitely related to architecture.  No question.  As noted here, and something I have preached for about a year or more now, the Duo-R and RX are SIGNIFICANTLY more reliable than the Duo model.  I have yet to find a faulty R or RX.

But the reason is NOT the CD drive revision.  

All Duo, Duo-R, and Duo-RX systems have identical CD drives.  You can swap between all the models flawlessly and the CD drives appear to have the exact same technology.  Remember, Duo systems were only made for approx 1 year.  Not a lot of time to be rolling out revisions.  

How do I know it's not the CD drive?  I took a CD drive from what appeared to be a faulty US Turbo Duo and slapped it inside a Duo-R.  Worked PERFECTLY.  You want to test your audio performance try either Gates of Thunder or Valis II.  Both strain the drive a lot and you'll quickly discover whether your system is on its way out or not.  So, it NOT the CD drive that's at fault.  It appears to be the sound amp/processor.

And this is a logical conclusion.  If you look at the inside of a Duo compared to an R or RX, the innards, while identical in terms of what the actual components are, are all shifted.  And one thing shifted is the location of the op amp chips for the audio.  Ever feel the top of you Duo, R, or RX?  The back left corner gets quite hot on any model.  That's where the huge heat sinks are.  And you ever notice where you black Duo AV port is?  Yep, right next to the heat sinks.  Yet on an R or RX, it's at the back and the audio circuit seems to follow suit!  And those audio op amps are only rated to 80 °F!!!

I have been offering for about a year now to install a fan in the Duo AV port and it really makes a difference in the latent heat effect.  Of the 4 or 5 systems I have done the fan mod too, all are still chugging along with no issues for the users.

But, can malfunctioning Duo's be fixed?  

I am working on that.  And it's a very very VERY slow process  

[TurboHuC6280]

Now, the reason for the sound issue to me is the biggest problem to tackle and undoubtedly the one most people are dying to have fixed.  And the problem is definitely related to architecture.  No question.  As noted here, and something I have preached for about a year or more now, the Duo-R and RX are SIGNIFICANTLY more reliable than the Duo model.  I have yet to find a faulty R or RX.

I've been wanting to look into this CD sound issue that many people talk about.  I've not had a Duo yet to examine its guts though (only CDROM briefcase systems).  Does there happen to be a DAC anywhere in there that might be going bad?  That seems like the most likely failure point to me, aside from perhaps an op-amp or a capacitor.

I'm really hoping to score a few bad Duos here soon, so I can also try to trrace this issue.    If anyone has any Duo systems with this problem, and they wish to get rid of them, please let me know.

[D-Lite]

Now, the reason for the sound issue to me is the biggest problem to tackle and undoubtedly the one most people are dying to have fixed.  And the problem is definitely related to architecture.  No question.  As noted here, and something I have preached for about a year or more now, the Duo-R and RX are SIGNIFICANTLY more reliable than the Duo model.  I have yet to find a faulty R or RX.

I've been wanting to look into this CD sound issue that many people talk about.  I've not had a Duo yet to examine its guts though (only CDROM briefcase systems).  Does there happen to be a DAC anywhere in there that might be going bad?  That seems like the most likely failure point to me, aside from perhaps an op-amp or a capacitor.

I'm really hoping to score a few bad Duos here soon, so I can also try to trrace this issue.    If anyone has any Duo systems with this problem, and they wish to get rid of them, please let me know.

I'll be selling a number of them soon, with varying degrees of the issue.  Watch the selling forums.

[TurboHuC6280]

I'll be selling a number of them soon, with varying degrees of the issue.  Watch the selling forums.

Excellent.  

[esteban]

Well, as someone that has modded about 50 Duo systems now, I have seen a lot of guts of these things and lots of problems with them too.  Far and away the biggest issue is red book audio....

EXCELLENT info on the hardware issues.  Thank you for clarifying these issues. If you have the time and / or inclination, I would love to hear about any of the other interesting apsects/problems you've noticed on TG-16/TG-CD/Duo/Nec hardware.

Or any links/references on these issues that you feel are credible.


ON THE CD DRIVE DEBACLE:
I haven't really tried to play many CDRs on either my DUO (US) or TG-CD. But I can tell you that my TG-CD is FAR more reliable and stalwart at reading super-scratched *original* music and game CDs.  My DUO, on the other hand, is far more finnicky.  For some games, I rely on the TG-CD.

ONE THING TO KEEP IN MIND WITH CDRs:
If you have a sloppy / imprecise burn of a game, then that is the source of some of these problems, not the hardware itself.  I asked my brother to back-up some of my games, and the first 2-3 attempts had limited success on DUO (I don't think I ever tried TG-CD).  Often, the CDRs: 1) did not work at all, DUO vainly tried to read the disc and 2) the game would work for a limited amount of time then freeze/become unplayable (opening cinema plays -> freeze, halfway through 2nd stage of Spriggan -> freeze). Eventually, though, he burned competent back-ups that worked pretty well on DUO.

ASIDE:
I have noticed that my older audio component CD players (84-86) are MUCH better at handling scratches on CDs than my "new" ones (97-99). They are all from comparable models ($200).

I don't know what to make of this.  I just assumed that my newer players were designed with a quicker "planned obsolescence" than the older ones. In general, I think Sony sucks with home audio CD players.  Nearly all of my players (4-5) have experienced "whirring" and "scratching" noises/problems (among other things).

[PCEngineHell]

Are you guys using "short strategy" or "long strategy" cd-rs?Shorts have weak dyes,and you can barely see the burned image on the disc.Shorts also do not have as long a shelf life.About any wal Mart carried cd-r is short strat.
Maxell Pro cd-rs are long strat.Infact,the best way to tell is look at the country of orgin on the package before buying..
Japan is long strat,Taiwan is short strat.

[PCEngineHell]

Back to the LD thing again,just wanted to point out something to any of the Star Wars normal CLV release owners,the Empire Strikes back And Return of the Jedi are sped up 4 percent to get the movie to fit on the disc without spreading them out too far.Alot of people dont know this,The CAV versions are fine however.

[TurboHuC6280]

Are you guys using "short strategy" or "long strategy" cd-rs?Shorts have weak dyes,and you can barely see the burned image on the disc.Shorts also do not have as long a shelf life.About any wal Mart carried cd-r is short strat.
Maxell Pro cd-rs are long strat.Infact,the best way to tell is look at the country of orgin on the package before buying..
Japan is long strat,Taiwan is short strat.

I've never heard of it referred to that way, but I do know that Japan makes the best CDR discs (e.g. Taiyo Yuden  discs).  Most discs are made in China though.  I've typically unly used them, and have had great success.