New user and two issues - top fill and nozzle leaking

Hello!

I just received my Solidoodle 2 and so far it has been a mixed experience. The first few prints all had the issue that the object didn't stick to the print bed. What happened was that the first 5-10 layers were fine but after that, it started to come off.

I then went through the forum and adjusted a few things - print speed, temperature of first layer and also reduced the z-distance slightly. That seems to be an issue. It now sticks to the bed BUT the printer now can't seem to put a 'roof' on objects I print. I did a few test prints of a simply block and even though the bottom and middle are fine, the last top fill layers to close the internal structure all don't work. The nozzle slightly hits the structure and there seems to be not enough space to extrude enough material to close the gaps.

If I change the Z-setting (screw) back, I might be able to close the top of the structure but I don't even get to this point as not one object sticked to the bed (see above). So this is somewhat unsatisfying

Second issue so far is that my nozzle seems to leak a lot. Once the extruder has heated up (even before the print), there is a constant stream of tiny plastic string coming from the nozzle. I have to clean it every time before starting the print process and when I wait another 10 seconds or so, there is at least another small plastic string of at least 1cm hanging from the nozzle. Is there anything I can do to stop it, change the pressure screw on top or something?

Ohn, and a maybe silly question but the leds illuminating the print bed are flickering slightly, I would say maybe with a frequency of around 50hz, I think it might be the power supply for that reason as we do have a frequency of 50hz in the UK, so maybe the voltage coming from the power supply is not 100% perfect.

Any ideas - much appreciated!

Thanks

Alex