Turbo Duo on it's last legs?

[zborgerd]

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/

[zborgerd]

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  

[zborgerd]

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.

[zborgerd]

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).

[Michael Helgeson]

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.

[Michael Helgeson]

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.

[zborgerd]

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.