I recently purchased a Berlan Thicknesser-planer (Dickenhobel) BDH1800-254 from werkzeuge-online. Good price and it arrived quickly, but on arrival the height adjustment did not work. The right side screw turned with the handle, but the action was not transmitted to the left screw because the bevel gears on the transverse shaft did not engage properly. To put this right, I had to dismantle the transverse drive shaft and grind down the lugs that hold the bearings for the shaft - I used an angle grinder for this. You should not have to take an angle grinder to a new machine to get it working! Taking 1-2 mm off the lugs raised the bevel gears on the transverse shaft so that they engaged the corresponding gears at the bottom of the two vertical screws. So now the thickness adjusting mechanism works OK.

The actual planing action seems to be quite good considering the price of the machine, but if you are considering bidding for one of these, you may have to be prepared to make some such adjustment as this before you can use it.