I finally managed to obtain an ADV11-C without parting with a large sum of money, but unfortunately, it didn't solve my problem. The system still hangs at the same point it did when I used a DZ to "fake" the ADV11 by setting its CSR to 770400. If I remove the ADV11, the program runs, but it is forced into its simulate mode because the missing hardware. I set the vector to the default on the DRV11, DRV11-B, and ADV11-C. I didn't check the serial module though. Could this be a vector setting problem, or do I have the wrong symptoms? Is there anything I can learn by halting the system when its hung and looking at addresses in memory? I did try doing a "770400/" and it returned 000000, with the module out it gives a ?, so that seems good. 770402, the data buffer returns 007777. Does anyone know what to try next? I'm running out of ideas. The only difference between my system and the one I'm trying to replace is that the backplane is 4 slot instead of 9, I don't have a BDV11-A like the original had, and I have a DSD systems generic RX02, instead of the real DEC M8029. Also, do the limit of backplane space, my modules are in a slightly different order. Thanks again, Tom

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