This article describes how to troubleshoot communications problems with the Pressure Control Module (PCM) of a 6270A pressure controller. PCM communications problems can also cause problems powering up the 6270A. See this article for information on boot issues,
6270A not booting or not powering up fully
This article does not address control issues. See this article, 6270A Pressure Control Module (PCM) Valve Inspection
For communications problems, check the control screen in 6270A to check if PCM serial number and coefficients are present. Example screen is below and the menu path is: Setup --> Diagnosticc --> Control --> Primary
If the serial number or coefficients are not present, the 6270A may not be communicating with the PCM. See this article to remove the cover of the PCM for further inspection,
6270A Pressure Control Module (PCM) Valve Inspection
Review pages 15 to 17 of the 6270A Service Manual at this link to check that the LED indicator lights indicate correct communications,6270A Service Manual, Spare Parts Info
Please check that metal foil EMF shield is not touching any PCM components, especially the circuit board. The shield is supposed to be affixed to the inside of the PCM enclosure away from the circuit board (left side of PCM). It it touches the circuit board it can cause malfunction or damage to the circuit board.
The PCM firmware version is labeled "Revision" and is under the Serial Number. The firmware version can be checked or updated with this article, 6270A firmware update instructions, by USB cable
Contact Fluke Calibration Pressure Technical Support at the below link with questions or findings.