Under Rating A, simple maintenance of components installed in the aircraft can be done according to the CMM, which can even be disassembled for better access, as long as they do not involve extra maintenance of the aircraft. These tasks are released by the CRS of the aircraft where the component was installed.

• If the component is on condition, it is sufficient provided that block 12 indicates the tasks performed in the inspection/test and the maintenance data used (or there is traceability to the documentation where the information can be found).

• If the component is hard time (on condition with maintenance), this Form 1 would only be accepted if block 12 contains information about the last time the corresponding tasks were performed, or if Form 1 accompanies the relevant documentation with the last completion of these tasks. Preferably both.

Certifying or releasing a maintenance task by means of a TLB, CRS or EASA Form 1 is considered to be the last action in the production process of a maintenance facility, and this task is the privilege of the certifying staff duly authorised to do so. A Quality Manager of a maintenance centre, as well as the Quality System auditors, should not be involved in this production process (AMC 145.A.65 (c) 1-11), since when managing/performing quality audits, an essential component of the Quality System, the required independent nature of the quality system would be infringed. 
 

Oh, yeah, yeah. In relation to maintenance of aircraft components by an organisation with rating A, maintenance not covered by the AMM and yes by the CMM, Regulation 1321/2014 makes two references: 

There is no limitation in the standard or in the EASA guides that prevent a certifier from performing critical tasks in its first year.  
However, the organisation may add additional requirements in its maintenance organisation manual.

A B1 can perform transponder check tasks, as long as: 

• Use automated testing equipment (which does not require previous calibrations)
• Test results are GO/NO GO 
• Be trained in the use of such equipment.