VERY unhappy with PX-760A

I just purchased 2 PX-760A drives from ebay, and they both work, can read & write both CDs and DVDs, I must say this drive is not "all-that".

I use Taiyo Yuden DVD+R 8x media exclusively for burning DVDs, and I sacrificed a disc to do a full AutoStrategy entry for the media, which claims 12x speed, however no matter the application I try to burn a disc with, it NEVER is able to burn higher than 2x (less than 2x actually).

CD burning seems to be fine, DAE seems to be OK (not as good as my Plextor Premium or even my PX-716A, but acceptable). I've not tried ripping a DVD with it yet, but this just seems absurd to me that it burns at less than 2x!!!!

The drives are currently in an external enclosure (Vantec NST-530U2 which works fantastic with the Plextor Premium), but I do plan to hook the drives up internally to try to eliminate the external case as being the source of the issue unless someone here can offer up a solution to this slow burn speed with this reference quality media mentioned above.

Are these used drive? If so they might be on there way to the grave.

Check your DMA settings first, i think that it should be in udma4 for this drive.

Yes, the drives are used, but they test out and work well enough to write and verify data, etc., just very slowly.

Since they are in a USB enclosure, I cannot turn on the DMA setting, but even running PIO they should be capable of writing faster than under 2x! I have a 740-UF drive which writes at 16x with this and other media, and it too is external (although it is actually a BenQ drive with Plextor firmware).

Once I get my other Plextor Premium CD burner tomorrow, I plan to hook them all up internally (one at a time) and do some more testing, but thus far I am not at all impressed by the 760 series, preferring instead my 716.

The problem you describe is most certainly a DMA one. Apparently the drive and the IDE-to-USB bridge that is built into the case cannot agree on using UDMA. A speed in the 2-2.4x range clearly indicates a fallback to PIO has happended.

Here's what you can do/check:

• Are the PX-760 running on latest firmware?
  
• At my best guess the IDE-to-USB bridge in these cases is either "Cypress" or "ALI". Check if firmware-updates exist.
  
• Did you check the jumper settings on your PX-760 when you got them? Make sure they are jumpered to MASTER.
  
• If jumpered to master and a FW-update does not help or exist try forcing the drive into multi-word-dma. This is done by setting a jumper on both the "master" and "cable select" positions.

If nothing of this helps your only choice is to change for another type of enclosure/bridge combination. Unfortunately several of those IDE-to USB(/FW) bridges are far from being truly universally compatible. So check first.

1. Make sure the drives are set to master when installed in the enclosure.

2. Make sure the drives have the latest firmware, which for the PX-760A is 1.07:

http://www.plextor.be/firmwares/px-760a.html

3. Run the program PX-Info, so we can see just how used these drives are:

http://www.plextor.be/docs/download/PXInfo.zip

4. Please verify for me whether the chipset used in the bridge of the enclosure is made by Cypress Semiconductor. Use a dignostic tool or open the enclosure up and look for a chip that has the letters "CY" and some other numbers following it. There is a known problem with many Cypress-based bridges where the DMA was not set properly at the factory, and you need to modify the chip to fix it and allow for full speed DVD burning. Here is the relevant thread in the External Enclosures forum:

http://club.cdfreaks.com/f143/extern...ypress-190288/

5. Basing your evaluation of the PX-760A on a couple of used drives from eBay is faulty logic of the highest order. Unless you are an expert at spotting good used drives, you could have gotten completely shafted and taken for a ride, and it would have absolutely nothing to do with the quality of the PX-760A, but rather, would simply be a statement on the fact that you didn't know what you were doing. You have to be very careful when buying used drives, especially on eBay, and in regards to Plextor drives especially, there are all sorts of things you need to evaluate beforehand, long before you make a purchase or bid on an auction. We have no idea if you did any of that, so your comments about the PX-760A have no relation to reality.

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Last edited by negritude; 16-07-2009 at 23:08.

It is set to master.

Yep, already flashed to 1.07.

Apparently it doesn't display times when used in external enclosure, as I tried this too.

What diagnostic tool can I use?

I have been a Plextor customer since the old 4-Plex, have at least 3) 6-Plex drives still, several other assorted Plextor SCSI drives and every burner I have bought to date has been a Plextor, so I believe I know what I am doing in regards to Plextor drives.

You're right in that my disappointment may be that I got bad drives, or perhaps due to the enclosure used. But, the same enclosure works flawlessly with the used Plextor Premium I got last week, and I expect it will work fine with the second one being delivered tomorrow.

I plan to put the drives into my desktop over the weekend plugged in internally, so I can pull more information and do further testing with them before I pass final judgement. At this time I would have to say that I am happier with my 716A drive than with the 760A. Just my opinion, which may be premature, but still a valid observation.

It is a Cypress apparently. The chip is marked as shown below.

CY7C68300C-56PVXC
B 04 PHI 0849
CYP_ 653395

I suggest using a USB enclosure with the NEC chipset. That works great for me with the 760.

Here is the one I have - it is cheap and works! I would suggest disabling the fan as you really don't need it with most optical drives.

http://www.newegg.com/Product/Produc...et%20enclosure

sorry n/m

Can you tell me the model & brand of the case, the link doesn't seem to work?

Never mind, I figured it out:

Syba SD-U2DEL-525 uses the NEC Chipset and is only $18.99 from NewEgg!

The link works fine for me -- not sure why it isn't working for you.

Try the link without the extra stuff on the end:

http://www.newegg.com/Product/Produc...82E16817186103

The Plextor Premium is a CD burner, not a DVD burner. A CD burner can work OK with a severe bottleneck, a DVD burner cannot. CD burning is not the same as DVD burning in terms of the throughput needed. You can't compare the two. I can take a crappy enclosure and use it with a CD burner, no problem. That same enclosure will be a complete fail with a DVD burner.

Speaking of bottlenecks: Is the cable in the enclosure of the 40- or 80-wire type?

The Premium only supports up to UDMA2 and works just fine with an old 40-wire type whereas the PX-760 supports UDMA4 and UDMA4 requires an 80-wire cable.

I hope you use USB2.0 connection, USB1.1 won't be fast enough, thus leading to slow write speed of course. So check your board whether it has USB1.1/2.0 connectors and whether you use the correct connector.

Why would you even purchase a drive from Ebay to begin with?....

You always run the risk of buying crap.

I've gotten my best performing Plextor drives from Ebay.

I have picked up 10+ original BenQs and a couple of Plextors from Ebay myself and all are still performing nicely. Just do your research on the seller before you bid.

Yes, it is a risk buying from eBay, which is why you have to do research on the product you are buying, knowing it backwards and forwards, and you need to make an intelligent evaluation of the seller. Most people do neither, which is why they get stuck with junk all the time.

If you approach eBay buying with some common...or rather, not so common sense, you can find some great deals, especially on products that are no longer being manufactured, and can't be bought new (at least, not at a reasonable price).

I don't use eBay to buy currently manufactured products that I can get somewhere else like NewEgg, I use eBay to buy rare and valuable tech items that have been discontinued and/or didn't find a mass market.

PXinfo does display accurate information, including burn times, when a Plextor is installed in an external enclosure, so I know your enclosure must be broken or otherwise crippled.

I have a PX-760A sitting right in front of me, that I recently got off eBay, and which I currently have in a Prolific PL-3507 based enclosure. The first thing I did was connect it via USB, to check usage with PXinfo and upgrade the firmware. It worked. I've done the same thing with Plextors installed in other enclosures, with different chipsets.

There you go. Your enclosure is crippled. Check the thread I linked to for instructions on how to fix it.

I returned the Cypress enclosures, and now have enclosures with NEC chipsets installed in them. PXInfo still shows no usage information from either PX-760A drive in my system. Flashing the drives works fine, everything else works fine with them now in the new enclosures in terms of speed, etc., aside from PXInfo (1.24) not providing the time information.

I tried PXInfo 1.26 but it fails to run (crashes) on my system.

Also, both Plextor Premium drives reported the burn time using PXInfo in all enclosures, so I think there is something funky with the 760 drives which are not reporting the time used. Maybe they exceed the maximum value or something?

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Last edited by Bob_Collins; 27-07-2009 at 17:44.

Please post what PxInfo 1.24 reports.

I'll try post this later, but what it shows is that inside the brackets which are supposed to contain the time information, there is nothing. The brackets are butted up against each other [].