Dazp1976

Turned out... Faulty extension leads broke reciever and some motors. Fixed that and it works just as good with 2XL motors in driving configuration, front 2 and rear 4 axles. Had issue with engine jamming. Putting part 15100 either side of the black 12T gear (connected into the grey part 64719) stopped gear spreading out and sliding sideways. Slightly changed the gearing configuration of the boom extension, and installed a retract wire. Now I just need to sort out the counterweight. Bought a Mould king control set with controller and 2 lithium reciever boxes. Has a lot more grunt.

Well. The brick quality is fine. No problems there. Having 3*XL motors on the drive just seems to make the batteries dump!. Even my lithium based control set. The AA reciever just shuts down or the lithium box cuts off. The way the lego actuator is designed it feels there's a lack of support on the non motor side. Makes it twist a bit so just have to give it all a squeeze together first and it lifts without skips. Crane does look smart though, I'll give it that. I'm going to rebuild it with a few tweeks and less rushed, and try using just 2*XL. 1 on front 3 and 1 on rear 2 axles. My other large 4 axle crane is heavier and ran really nice with only 2 XL but Mrs said it was too big!. (A bit wide tbf).

Built mine but.... It runs like a stuffed pig!. M'eh!. The actuator skips like mad trying to lift the boom from bottom most. And the wheel motors just seem to have low power (even with new batteries). Burned out one of the small gears in the top of the boom extension mechanism too. At least I got the wire right on the inner boom, I suppose that's a win.

This is the one below. It's made with the Chinese knock off bricks, not official lego. I have no complaints so far regards brick quality on the models I already have. https://m.aliexpress.com/item/1005005206641920.html?

Looks good. I've came across the MKIII for sale on Aliexpress. They're emailing me their instructions so I can check it's the correct chassis build before buying. It looks to have a large custom lego built actuator on the boom (for now). I'm also going get it in green and not yellow, just to be different. I recently finished a YC22003 happy build crane but it has design niggles. I want something that works!.