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[funky26cro]

u people are crazy u will fry your lasers in guide it clearly says go down in 100k increments ,every time untill u find good seting some people here go from like 5.0 to 3.0 in one go ,u must go let say my hitachi was totaly screwed dident want to read anything and default was 4.2 i was doing it first to 4.0 tested worked but not quite done 3.9 better but not quite i settled at 3.7 and its like brand new never got dirtey disc error again and that hitachi is like 3 years old and still working after that mild pot tweak u must do it in little increments and test it every time now my new liteon is fuked up it just gives me dirty disc error on verbs in middle of playing here and there no matter on what game it just stops will try it on me liteon now here is see they have difrent reading spots

[wyldstallions]

I dunno that the laser itself craps out over time personally I think its the focus maybe because of the shear amount of heat that ends up in the drive.

When you switch it on the lens assy pops up and down to adjust focus, you can see this if you don't have the top on (don't look at the laser unless your want to do some homebrew laser eye surgery). It seems to calibrate it. So if you have a disk that won't play go from a cold reboot (plug put job) it forces the laser to recalibrate focus.

I guess over time this becomes weaker and leads to more problems.

I've also found that adjusting the laser rails can yeild just as good results as the pot adjustment but its much easier to to make a mess of it. It can take hours to get the sweet spot as you can adjust laser distance and angle. Different drives have different adjusters.

[dayvey]

QUOTE(Epaige @ Nov 23 2009, 03:47 AM)

Also to anyone going down lower than 4.0 and still having problems, You may want to try cleaning the laser lens if you havent already.

For anyone opening up their drive for any reason - I'd do this anyway. Takes a few seconds with some high purity isopropyl alcohol and a cotton bud (cue tip to our American friends), but as long as you're carefull it can only help prolong the life of the laser. If you're at the point where you need to pot tweak then this is an absolute must - why turn the power up more just to compensate for the few years worth of smoke and dust that's settled on the laser?

Infact - almost every drive I've opened that was more than a year old needed a damn good clean - brick dust, fluff, cat hairs, toast crumbs - you name it I've seen it in there. Again, as long as you don't damage anything in the process, it'll help your drive functioning properly for longer (and in the case of the sammys help prevent the damn sticking tray issue) if you deal with this when the opportunity arises.

[neophyte5001]

Hello everyone, this is my first post and I am fairly new to the scene as I purchased my first 360 last Oct. Promptly flashed 1.6 to my lite-on before I realized the ban wave, wait for LT (which doesn't seem to be coming anytime soon), etc. But sorry off topic.

            Today I started having the open tray issue and with a bit of googling (really is your friend) I found this thread.

            So far everything I have read about the Lite-On here has not been accurate for me. None of the pictures look like mine, and my Ohm readings were much lower, but it is a newer Lite-On so... I looked at the drive facing up and from the back, with both metal sides off. Interestingly enough, you don't have to move the PCB, or undo cables or any of that. Simply slide the laser toward the front, and the pots are right there! I adjusted the one on the left from 4.2 to 3.8 with no joy. I finally settled on 3.2, cleaned the lens while I was at it and I was back in business.

             Anyway just wanted to contribute my experience to the community in furtherance of collective knowledge, and thanks to all those who have contributed to this thread. Between everyone anybody with a tad of know-how can fix this issue now. Long live the interwebz!  (IMG:style_emoticons/default/biggrin.gif)

[d-2-d]

So thinking my laser is totally shot and not going to work i messed around and slowly turned it down to 0.558k Ohms it now is reading the games but I doubt the laser will last more then an hr. I will update the scene on my failure soon.

[jonesyiv]

I'm pretty pleased with my efforts for tonight.

A friend sent me down two 360's which both had different faults - one wasn't reading disks and the other was RRODing intermittently.  I swapped the DVD drives over and have shipped him a working console - leaving me with the two broken ones as payment.

Anyway, i've replaced the X-Clamp on the RROD unit and it seems pretty stable now - i've had it running for a good few hours with no problems.  I realise i'll be living on borrowed time but I figured for free it's not bad.

I was all set to order a replacement laser for the Benq drive when I came across the pot tweak trick.  I'm happy to say that i've dropped it down to 3.22kohms and it's reading everything perfectly now.

Of course I realise i've probably also reduced the lifespan of the laser diode but i'm not so worried about that.  When it finally does pop i'll replace it - but for now i've managed to drag a bit more life out of the current unit.

[Shonk]

My son's friends drive has been flakey since new

its not modded at all and stopped reading origonals around 8 months ago
dirty disk error's cleaned the laser with iso-propanol at the time

has been ok ish since with the occasional dirty disk error

decided to do the pot today
at the same time as cleaning the laser

its a liteon was default 5.17
set it to 4.28

seems fine so far

i was aiming for 4.50 but its not my drive so wasnt spending all day messing

This post has been edited by Shonk: Apr 2 2010, 09:42 PM

[metaphaze]

I attempted the DVD Pot calibration on a Hitachi 47DJ drive. I have had this drive modded for years now. Over time the laser has become weaker and weaker. I can always boot my originals, but my backups have become harder and harder to boot.

I have a real POT issue, unlike the first nine pages where "most" seem to stem from poor media, and other related issues.

I started off at 4.22ohm and knocked it down 4.00 a more then happy balance IMO.

However the drive will no longer "spin-up". The laser head moves back and forth for calibration when powered on, but it will no longer attempt to read the disc after performing the calibration.

This leads me to believe one of the traces on the cables was damaged (although I took the upmost caution this isn't my first rodeo).

Can anyone confirm or deny this to be the case? If so can I troubleshoot which cable may have been damaged?

This post has been edited by metaphaze: May 18 2010, 11:25 PM

[iateshaggy]

just get a new drive, 100% of successful pot calibrations i have ever done just resulted in having to get a new drive a month later anyway.

[metaphaze]

QUOTE(iateshaggy @ May 18 2010, 05:40 PM)

just get a new drive, 100% of successful pot calibrations i have ever done just resulted in having to get a new drive a month later anyway.

What do I need to do now a days for a drive swap?

I no longer have the original f/w dump and key for the drive since that computer is long gone and I forgot to back it up.

Am I SOL now?

ETA: Since the drive isn't bricked but has modded f/w can I still extract the key? I have been out of the scene for awhile.

This post has been edited by metaphaze: May 18 2010, 11:50 PM

[xbox360sexual]

You can swap the PCB over to a new Hitachi enclosure, or replace your current lense, or extract the dvdkey and inject to a complete new drive. There are many options available to you.

[lego28018]

My xbox is giving having random read errors and open tray. I suspect that it is the laser unit, and having already invested in media (memorex.....Uggh) I cant see not trying a new laser at this point. Could moda or someone suggest a part number of the best laser I can buy?

[silentv8]

Thanks to Moda the "condemned" drive of my son's XBOX is now alive and working.  However, there are still some things I figured out by myself as important as the laser power calibration.

Our drive is the HITACHI GDR 3120L ; and here goes how I fixed it.

Initially, I did the drive cleaning instructions without success.  Drive motor was spinning, laser was .... lasing.  I figure ... hell, I was asked to get a new drive so I have nothing to loose if I tinker with the drive and fry it.

The initial setting of our pot was at 4.1KOhms, got OPEN TRAY message on all discs.  Reading through Moda's post, he finds i believe at 3.4KOhms the nominal value.  After several tries adjusting by .1KOhms, I got tired and went down to 3.4KOhms without success (suggested min is 2.8K).  Since I did not want to stress the laser further, I thought about 2 things ... there is an electronic adjustment which is the pot ... there must be a mechanical adjustment as well.  And true enough ... the bottom side of the motor has 2 springs with screws... these springs adjust the height of the disc.  So here goes my adjustment procedure.

FOR TESTING PURPOSES, GET YOUR OLD DVD MOVIE - THE ONE THAT YOU HATE WATCHING, IT IS A STRONG POSSIBILITY THAT YOU'D SCRATCH THE DISC.  I DID, ON A XBOX GAME - LUCKILY THERE ARE INSTRUCTIONS HOW TO REMOVE SCRATCHES  - YOU ARE WARNED.

INSTRUCTIONS ON DRIVE DISMANTLING YOU CAN FIND ELSEWHERE.
READ FULLY FIRST BEFORE DOING ACTUAL WORKS.

I left the pot at 3.4KOhms ... loosened both screws with springs at the bottom side of the motor. Others suggest mark the position and count the turns, I did it without marks and without counting hence the disc scratching.  Have the screws just touch the metal plate without pressure - i did this by going clockwise and counter clockwise a few times until I am sure that the screws are just touching the metal part and did not apply any pressure to the springs.  This was just for me to make sure that I tighten both screws evenly - hopefully having a level motor preventing disc wobble.  You screw in both with the same number of turns, until you see the flat area of that black spinning thing ( where the disc rests ) is approx 2mm ABOVE the laser - test with the DVD MOVIE - DRIVE ENCLOSURE NOT IN PLACE  ( you need that part on the top enclosure that locks the disc in place, you pry open that round metal plate to gain access )

TOO LOW AND THE MOTOR WONT TURN
TOO HIGH AND YOU GET OPEN TRAY
MOVIE PLAYS AND YOU GET UNREADABLE DISC OR MOVIE ISN'T SMOOTH, YOU ARE STILL A BIT TOO HIGH, I WOULD SAY LOOSEN SCREWS 1/2 TURN.

LOOSEN = LOWER / CLOSER GAP OF DISC TO LASER
TIGHTEN = HIGHER / FARTHER GAP OF DISC TO LASER

I suggest you try and achieve OPEN TRAY to identify farthest possible gap, then adjust appropriately loosen 1 full turn each  test.  Fine tune, 1/4 to 1/2 turn once you get the movie playing ( TIP:test the last chapter of the movie to have laser read farthest from center of disc)

Notes:
1)  if the 2 screws are not even, there is a strong possibility of disc wobble.  
2)  the more gap you have, the lesser chance you'd heat the disc.  

Should you get wobble and you want to make sure your disc doesnt get scratched due to wobble, put soft dampers on the top side of the drive enclosure-other brands have these.  It is better to use softest material you could find.  I used the softest rubber i could get my hands on, it made noise when wobble occured.  I did, 3.75mm damper thickness (with a caliper and emery/sand paper) - adjust thickness appropriately so that disc would turn freely.  There are instructions you'd find around for this mod, just look for them.  The above spring adjustment, I have not seen anywhere.

You should get the idea already, apply this with an XBOX Game and adjust appropriately.  Test as much game as you could before closing everything.

Again, this applies to the HITACHI GDR 3120L ; I would presume this to be the same on other drive brands - maybe there would be no springs, you could make spacers to adjust disc height.  Just make sure disc height is above the laser.

Hopefully somebody would find this info useful.


MY RESULT: NO DISC WOBBLE, A QUIETER XBOX, EVERY GAME IS RUNNING WITHOUT PROBLEMS. ALL MOVIES RUNNING WITHOUT PROBLEMS.  ALL THIS FROM A CONDEMNED HITACHI GDR 3120L DRIVE.

[mike3671]

The pot tweak did not work for me so I am going to replace the laser. Do I need to do any adjustment on the new unit or does it come factory set?

[hobogoonie]

Hi Mike, A brand new laser will come with a couple of little solder blobs on the side that need removing before you install the new laser. Do a quick search. I'm not great with a soldering iron but they were easy enough to remove.