Monoprice Maker Select 3D Printer V2...Basket Case...

All,I am new to 3d Printing but not the computer industry (40+years - 22+ years as a professional IT Developer).I was recently given this printer to me by my sister. She said she over the last few years had done some upgrades/fiddling with this 3D printer but has gotten to the point that she does not have time to fiddle with it any longer as she has 3 other 3D printers...As I was considering picking one up but honestly did not know which one I went with her offer. Anyways its a basket case...she said she upgraded the Mosfet recently...which looking at it appears to be a small PCB board. Unfortunately she also said it stopped heating the bed. I am not certain if the two are related or not.Upon applying power (plugging things in and being careful not to short anything as the PSU and its case holding the board is not attached) I do not see any LCD Screen lighting up on the unit as well. So I have no screen activity nor any heating bed....I have taken some voltage readings and the power supply appears to be putting out 12.3 V at the supply and I get similar readings on the Main (Motherboard) board and the Mosfet board has a red light.As I am completely new to this machine and 3D Printing I am coming for some guidance...What would be a good way to test things initially for troubleshooting?As far as the heating bed issue could I check for continuity on the heating pad using a Digital Multimeter?I believe there is a thermisitor involved in the heating pad as well...so I assume the Continuity test would be beneficial for this part.My main concern is why no LCD display ...Ideas?Thanks for the help!Chris