NEC3500a PI Fail spikes, design fault?



anyone know why the NEC3500a gives big PI fail spikes at 1.2 gig and a few higher places when it writes dvds?

it’s not a faulty writer, as I have tried several,all give spikes at 1.2gig, and I see other peoples scans with the same spikes.

Bit of a pity really cos Nero Quality tests will always report disks written using this writer as poor quality. (even tho the spikes don’t seem to do any harm)


This is a joke, right? Very funny.
If you are serious, try scanning at 4x, and try a good quality disc. I don’t know about ProdiscS03, but I have never seen a quality score below 90 and I have burned hundreds of dvd’s with my 3500.


As you know you must scan at 4x and and I have noticed 811s is unreliable for doing scans, it likes an dislikes some media.


The ND-3500 and ND-3520 tend to burn a disc with a few PIF spikes at 12X and above write speed, apart from on a few media’s this never seems to cause a problem regarding reading the burned disc.
Regarding scanning on Liteon drives, 4X scan speed should be used.


If you look at other peeps scans of -R in this forum, they also often have the 1.2 gig spike. The 1.2 gig spike occures at a 4.5x read speed, so not sure read speed is significant here. (same media written on my nec2500 and Benq 1620 don’t produce this spike)
This spike appears on every 4x and 8x burn of dvd-r media, that I have made on this writer, so I guess it’s a mechanical design flaw. Overspeed the media to 12x and spike gone.


I never saw those spikes at a specific place… they happend mostly at random places when I scan with my LiteOn 411. I’ve burned and scaned quite a few TYG01 and RITEKG04 discs written at 4x, 6x and 8x… and none of them had those spikes. It’s interesting that the spikes when they occure are all PIF from 9 to 12 (in KProbe).


When you are burning a disc, has no-one ever noticed (particularly at lower speeds of 2x and 4x) the recorder buffer, which usually hovers around 91-98%, falls at fairly regular intervals to 7%, then quickly recovers back to normal. On a 4x burn it happens as often as 7-9 times.

I’ve seen people blaming these brief drops in buffer level to multi-tasking but it happens even if all you are doing is burning a disc. At 12x, the drops still occur but are less frequent. I always thought it was something to do with the drive adjusting the spinning speed of the disc and always thought it was responsible for the PI spikes you are talking about.

I have 4 NEC burners and the brief buffer falls occur on all of them.
I used to have 4 Pioneer 105’s and nothing like that ever happened on them…


I have looked back at a lot of error scans for 4x and 8x burns with dvd-r discs. Not one shows those PIF spikes. However, one of the scanners commented about the bad quality of the scans his old Lite-On 811 produced. And that was at the recommended 4x scan speed.


Yes, everyone knows that the NEC readjusts its buffer; it has been reported from the first day it was on the market.


hellbitch: It’s caused by AOPC… and it’s normal.


Ah I see. If it’s not too much trouble, what does AOPC stand for ?
And is this something that happens with all high speed burners, ie. does it happen on the pioneer 108 or is it unique to NEC ?


AOPC - Active Optimum Power Control
It adjusts the laser power and write speed according to the quality of the media. Only some newer burners have this (or something similar).


the NEC and the BenQ both do this, BenQ call it WOPC (Walking Optimum Power Control)
the pioneer 108 doesn’t as it’s now very “old” tech.


My opinion of this is the drive has a little trouble re-linking after an AOPC interval. It should not cause any major problems but I think NEC could handle this a little better in the firmware. It is mostly for this reason that I think the BENQ 1620 is a better burner.