Need help diagnosing DRE on V4 PS2 (2 machines put together to try to make one work)

[JofCore]

Hello,

I recently acquired a PS2 from ebay that had a DRE and the old owner had put a screw thru the power/eject cable. I bought it off ebay because I wanted to use it as parts to fix my PS2, which I had managed to fry attempting to put a Magic 3.1+ modchip into it (see this thread for that info: http://www.psx-scene.com/forums/showthread.php?t=30562).

My PS2 (the one fried by me attempting to put a modchip in) would read discs fine, as I had previously adjusted it for a DRE a few years ago. Since then it would read games just fine..

My old PS2 is a V4 GAP, and from what I can tell (http://www.modchip.com/ps2/ps2id.htm) the one from ebay is a V4 NO GAP. First thing I tried was to simply swap the entire DVD drive from my PS2 into the one from ebay. After that swap however, I still got "reading disc..." forever, and then an eventual DRE.

So next I tried to just swap the laser, in case there had been some hardware changes to the DVD drive between the GAP and NO GAP versions.. Swapped the laser from my drive into the ebay one, put it all back together, but I'm still getting a DRE

When I put a DVD game into the drive, it does a "reading disc" for a while, and then eventually gives me a DRE. When I put a CD-ROM game into the drive, the PS2 recognizes it as a game in the browser. When I try to launch the game, though, it goes to a black screen, and spins the drive up and down, and then eventually just comes back to the browser.

I cleaned my laser using a q-tip and rubbing alcohol, and it is now much shinier, but still doesn't read discs

Previously (few years ago) I had adjusted my original laser using the pots on the laser assembly, and that fixed the DRE's. I tried adjusting a little more (didn't want to go to far for fear of burning out the laser too quick), but still getting DRE's...

Why would my laser/DVD drive work in my old PS2, but this one would be giving me DRE's? What else can I try to get a working PS2??

thx!

[JofCore]

*bump*

anyone?