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OG Xbox Forums => Hardware Forums => General Hardware/Technical Chat => Topic started by: dfect on April 29, 2004, 04:35:00 AM

Title: Lg Dvd-drive Mod With The 74ls00
Post by: dfect on April 29, 2004, 04:35:00 AM

Went finished yesterday with all the connections to an LG 8162 drive.

When looking at superfro's scheme/guide its almost the same, its just the Z point that is different. Anyway, found it after some hunting.


Here is superfro's scheme i used to connect with.

(IMG:http://www.xbox-scene.com/imageserver2/lg-dvd2/image016.jpg)

All seems right, eject the dvd works, but after some testing happends this..

When i insert a DVD/CD Evox says directly No Disc (just after the tray went in the drive).

It doesnt matter if i boot with the disc in or eject and insert disc (says the same).

Anyhow, Evox says Ejecting and Open so it should get some signals right i guess (X, Y?)


So i took the multimeter and checked the points with the following results:


When drive is closed:

B = 3.8v
A = 0v
D = 0v


When drive is open:

B = 0v
A = 3.3v
D = 4.2v



D-point always gets 4.2V , no matter if disc is in the dvd or not, is this right?

During to the D-points results i checked the Z and its connection to the NAND-gate:

Z gets 4V when disc is in drive after tray is in, when no disc is in drive it gets 0V. However, it seems like it gets 2 short pulses of 4V (like 0.5 secs each) when the tray just went in (to check if theres any disc?), this happends in both cases, if theres  no matter if theres a disc or not.

After the invertion (the output of the NAND-gate, and that leads into next gate with the Y-signal) it says 1.7V when drive is in and 1.5 when its not.., could this be the error?

However, if i just take the chip out of the socket and a disc is in drive it reads it and launches ok. (Evox says Init instead of No disc)


W-point (eject) is always 3.3V (when not pushing the button)



Any clue?, i've read all documents i can found during this even the dutch instructions, no luck though.

Gonna log the signals that my retail xbox drive is sending.. maybe can get a clue that way..

But i dont trust these gates.. why get an +1.7V output when +5V and +4V on the inputs, and 1.5V output when +5 and 0V. ?

Title: Lg Dvd-drive Mod With The 74ls00
Post by: dfect on April 29, 2004, 08:24:00 AM

Seems i figured out the probl.


When drive is closed:

D = 4.2v


When drive is open:

D = 4.2v


And should go down to 0v when tray is moving.


This should be the right values i guess, wonder what i should do to fix that though.., cant be that hard with some gates i hope.

Any tips are welcome :)

This post has been edited by dfect: Apr 29 2004, 03:29 PM