Whilst Turkish and British games are compatible not all PS2 games will play in all PS2's. You can play all European format games on the same machine, Japanese on the same, Chinese on the same or US on the same but not mix them. The only way of mixing the different formats is to use software like Swap Magic or similar. The way of telling is to look at the format types on the box - see below.
Japan and Asia: NTSC/J, North America: NTSC-U/C, Europe and Oceania: PAL, and China: NTSC/C
Unless your machine is chipped dont bother buying copies from local traders. We have one in our place in Fethiye and there is no problem with power supply voltage difference.