They're (not there) Keyed.

The Blu-Ray drive and motherboard are MARRIED at the factory with a KEY.  If you swap the motherboard, you need the blu-ray drive that came with THAT system.  Since you have a 60GB board, you will be  better off buying a new PS3 Slim, or used PS3 FAT, for what they are going to hit you with, for a hardware BwC motherboard and matching drive, or drive logic board.   The DRIVES must also be the same if you only get a logic-board. 

I can get used PS3s for 249.99 locally, and cheaper on-line.  Since the price drop and slim model, the older models, EXCEPT the 60/20Gb, do not have much resale value.  I still have a 60GB, and they are still selling for over 500.00 in the used game stores.  The Software or NO BwC are selling for 249.99, then they sell a year warranty (which sony offers on NEW) that brings the total to a NEW one anyway.

It is not worth the repair if you can't get a 60GB Motherboard and Matching Blu-Ray drive (or logic board) for well under 200 bucks.

80GB motherboards are going for 105.00 to 169.99 on Ebay with no BR-D logic.
60GB "                                        89.00  to  185.00                                      "

You need the married pair for it to work...

You can't, they're done by machine.  Some chips, maybe, but not the CPU or GPU in a home environment.