RAMPS D8 and D9 mixed up

After the accident with the first RAMPS I bought new one and it arrived couple days ago. I moved jumpers, steppers and wiring to it from the old one but I could not get it to work properly. The fan at D9 and heat bed at D8 were somehow bridged and worked at the same time. I didn't see any obvious soldering mistake on the back side of the board so I was quite puzzled. Some searches on the RepRap forum gave me a hint and the problem turned out to be MOSFET heat sinks touching and messing up the logic. Only a little bending was required and now the printer is operational again.

10 tips for RepRap P3Steel builder

These are my tips for anyone building a P3Steel printer. I did not purchase a kit so some of these might not apply for kit printer builders.

1. Get plenty of LM8UU bearings. Tolerances vary a lot so it is better to order at least 2x the required amount. They are cheap after all. Or use alternatives like IGUS.
2. Try to get printed parts in good quality and as a dedicated set for P3Steel. Using some generic Prusa i3 parts is possible but requires more manual work. Also, think about using upgraded parts like Toolson edition straight away.
3. For heat bed I have been using ordinary 4mm glass. It is cheap and available at local glass shops. So far I haven't had any heat related issues with PLA temperatures.
4. Plan for cable management. There is plenty of wiring going around and some of it is moving around with hot end etc. So you'll need also cable sleeves, heat shrink etc. 
5. Be careful with 8mm rods. Especially longer lengths can be bent when handling or hammering in to the frame.
6. After couple initial test prints, go around and tighten up all the screws. I have had screws falling of from flexible couplings and belt pulleys.
7. Purchase enough M3 screws in various lengths. Not only you need plenty for the frame assembly but you will also need them to put together cooling fan supports etc.
8. Z end stop setting needs to just close enough. No need to go mental as the fine tuning can be done in software.
9. Print from SD card in order to avoid connection issues and pauses with USB
10. Zip ties and hot glue. Shortcut to get first print out :-)