DVD drive strip down gallery

[stanwax]

Hi guys I took some images as I raped a DVDRW drive for its 200mW+ diode. Pictures with explanations here
http://photonlexicon.com/gallery/album60?page=1 oops that link don't seem to work try this instead

http://photonlexicon.com/gallery/DVD...ip-down?page=1

Rob

[dave]

nice work!

What model no. liteon drive did you destroy?

Edit: does anyone know whether the Liteon 18x drives are ok to do this to?

[stanwax]

Hi Dave I dont rememeber what the model number was and have actually stripped a few Liteon drives. Interestingly I did strip two that were not too different in age had different model numbers (though performance ratings/specs were the same) and they looked the same externally, but when inside the optical pickups were very different - even using different ways of mounting the diodes.
The X18 will for sure be good to strip, the method shown will apply but you may need to do some things slightly differently once you see the pickup assy. On the plus side the x18 should have more power for the visible diode. Incidentally I have driven a diode from a Liteon to 320mA which yeilded 208mW. I keep saying Im gonna do a full profile of one of these and plot a graph of current to power - one day

Rob

[JimBo]

What power are these diodes putting out while they are still in the DVD?

Jim

[stanwax]

Thats a good question that I don't rightly know the answer to although I did find a data sheet for a Mitsubishi diode that was designed for optical drives and was rated at pulsed power of 350mW and could operate up to (i think) 70 or 75 degrees celcius. The CW performance will never get to 350mW but if you cooled one enough and were very careful putting more current In im sure you could get some more than 210mW. I do keep threatening to max one out til it dies but up to now ive not had the heart

Rob

[dave]

Hi Rob,

What sort of driver are you using to run the diodes?

Dave

[stanwax]

I originally used a driver board from a CNI Green module turned down to a suitable level but recnetly I have built my own based on the same driver - using a single LM358 op amp with each side of the chip used to provide a twin driver for pairing up DVDRW drive diodes. This variant has an analogue/TTL input that is over volt protected by diodes. Output transistor is just a regular to92 npn device - in my case I use a BC337 as its good for 800mA (obviously there is one for each diode). I will be adding a photo of this driver when I add more pix to my gallery when I show you all how im building a small projector into the housing of a dismantled disco light with a DMX controlled pan and tilt head.

[dave]

Any chance of a copy of the schematic?

[stanwax]

Hi Dave
take a look here

www.stanwax.plus.com/laser/lddriver.pdf

Its not sophisticated, but it does the job.
The pot adjusts the max current which is done with the mod. input at 5V. The 7805 is optional I put it in just in case to provide the option of a higher volt supply input. If it is used it may need heatsinking 7v input would be 1.2W on the reg at 2x300mA. 12v input and you need to get shut of 9W.
I do have a pcb layout if ya want can provide in bmp or .lyt for Proteus ARES.

Rob

[dave]

Indeed, it does look quite simple

It might be worth adding some offset, so the LD is driven at just below threshold when the mod is at 0v.