Try determine if it's mechanical issue, like faulty mechanism/switch/microswitch/motor. you can try to supply power to motor from AA batteries in series starting from 1,2,3,4 and reversing polarity on motor. See if this have any effect and will open try or close.

Use multimeter and check if voltage coming to motor when eject is pressed, check try switches/microswitches for continuity on open close positions.

i disassembled the case then mounted the internal benq1640 in another pc and it still doesnt open.
i then disassembled that 1640 and saw that when i power it one and then press the eject button there is the carriage with the optical lens that moves a couple of centimeters and then comeback to its original position. nothing else. if i play eject again nothing happens.
Any suggestion to what the problem can be?

i could try to post a video of that if you want/need

Try to disassemble the casing - if I remember correctly, the screws are under the caps at the bottom.
Maybe some flex tape in the drive inside the motherboard got loose during transport... Such things happen.

It's always some idea bud, try it on ;)

I'll try to check that, is there anything specifc i should check?

I have a multimeter but i'm not sure where i have to use it to check motor mechanism (i'm not an expert on electronic check with multimeter)

To find those problems you suggest i think i could try a workaround dismounting the external case of the ew148b and trying to mount it as a standard internal PATA drive if it's possible.

Perhaps one of microswitches i damaged or stick and drive "thinks" it's in open position ? Mechanism is OK so it can contact microswitches ?

Do you have multimeter ? If so please measure voltage on mechanism motor. If you have bench PSU please check connect it to motor and apply voltage after desoldering wires to check if motor is in working order.

thanks for your reply :)
no it doesn't make any clear noise. i changed the "elastic inner gear" with a new one hoping it was the usual problem of old gear but nothing happened. i changed it without opening the case so i had nothing to re-assemble.
it makes just a very little sound every first time i try to press the eject button after i turn it on again. then nothing (i changed those inner gear many times on old cd/dvd burners but it is not the usual sound of a tray that try to open but cannot.)

Does it make any sort of noise ? does it want to open and just can't ? Perhaps inner gears don't lock properly ? Had you assembled it properly ?

Benq external EW164B tray don't open
 

Hi i ask again for some help here cause this is an old-style forum really useful. anyway, i bought an used Benq EW164B sold as "functional" but the tray don't open. The Drive is recognized by Windows7 and the yellow light blink 1 single time when i turn it on. If i press the eject button of the drive or if i used the eject option in windows7, nothing happens. It doesn't make any noise, i changed the "ring gear" of the tray too but it didn't help.
Does anyone have any suggestion? :)

Google-Translated: Cześć, proszę ponownie o pomoc, ponieważ jest to forum w starym stylu, które jest naprawdę przydatne. w każdym razie kupiłem używany Benq EW164B sprzedawany jako "funkcjonalny", ale taca się nie otwiera. Dysk jest rozpoznawany przez system Windows 7 i żółta lampka miga 1 raz po włączeniu. Jeśli nacisnę przycisk wysuwania dysku lub użyję opcji wysuwania w systemie Windows 7, nic się nie dzieje. Nie hałasuje, wymieniłem też "pasek pierścieniowy" tacy, ale to nie pomogło. Czy ktoś ma jakąś sugestię?