I got an old v4, with damaged DVD tray - it would just stuck not going in or out, and no modchip.
I did an quick test, powered on, tested tray, shut down and went to Modbo installation and try replacement.
After installing Modbo and replacing again, it tested it and noticed something strange:
1) it powers on OK first time from standby, but if I reset it after a minute or two, it gets "new console" problem (not so often and a takes a bit more work to find on google): instead of opening menu, it enters "first-time" configurator, where it asks for language, time, etc. and does that on every restart, until I power it off and leave for a minute or two.
In info menu (opened by pressing triangle), for console it either says: "Unknown" or "SCPH.30004" (note that it shows dot instead of minus sign, SCPH-30004).
Also, MC is not detected in this state.
After leaving it off for a few minutes, it's back to normal.
Any thoughts? I've checked at least 5 times for any shorts or bad wiring on modchip, but found nothing under magnifier, replaced some wires, I use thick IDE cable wire for 3.3V and GND wires so wiring is not the problem. Battery measures around 3V (so does all other PS2 batteries I have and which were working on other consoles).

2) Also, after opening and replacing broken tray, it doesn't eject tray anymore. It does pull the tray in but not out - by pressing eject button, it just blinks once and both console and drive behaves like it's ejected. When button is pressed again, it starts spinning disc.
It's not mechanical problem like it's stuck, as it goes in just fine, and using swap trick I can eject it fine too.
And it was working both ways before replacing.
Any thoughs on this?

Thanks