Hi,

I bought a compact Chiron FZ08S mill last year that I am setting up at the moment. The idea was to retrofit a remote buffer into the Fanuc 21MB control for increased transfer speeds and a larger look-ahead. Unfortunately this turned out to be more work than expected. I replaced the 2-slot backplane with a 3-slot version (A20B–2000–0890) and installed the Option 1 board (A16B–2200–0913) in the frame. That was easy, but I can't get the system to fully boot when everything is installed. I replaced the 2-slot backplane with a 3-slot version (A20B–2000–0890). When I place the Option 1 board (A16B–2200–0913) in the frame, the system boots only till the BOOT*SLOT*CONFIGURATION screen, which at least shows the additional module being recognized. The control runs software version DDA1-14.

The Status LED on the mainboard*(A16B–2202–0900) read 1011 while the Alarm IDs are 010. According to the Maintenance Manual this means "Waiting for other CPU’s answer" for the status message. The remote buffer board status is 0011 while the alarm indicators are 000. I have tried a couple of things to narrow down the problem:
-Fitting another - yet incompatible - Fanuc PMC board from a Fanuc 15 control resulted in the same boot screen hang.
-removing the communication module and the EPROM from the remote buffer board. Didn't change anything

Right now I am running out of ideas. What could be missing? Are the ROMs on the remote buffer boards specific to the type of control they are used in? I saw that this board is used among different series of Fanuc controls. Any ideas what else to check?

Otherwise I am very happy with the machine. After replacing all pneumatic tubes and a lot of cleaning the machine is in good condition.

Thanks