I have 3 Asante MC3NB cards that have AUI+Coax, and I'm working on converting them to 10base-T. The cards I have a Rev B2, C, and C2, and I also have a Rev C1 that is already AUI+10base-T for comparison. I had already done a schematic for much of the media section when working on the compatibility problem for the MC3NB that has AUI+TP+Coax, I've expanded on that to complete the AUI and 10base-T sections.
The conversion needs an RJ45 jack, 20F001 magnetics, 8 resistors, and 2 capacitors. Later revisions of the magnetics, 20F001N or 20F001NG, are available on eBay, everything else I got from Mouser:
R5, R14: 274Ω 1/4W 1%
R6, R10: 66.5Ω 1/4W 1%
R7: 806Ω 1/4W 1%
R12, R13: 49.9Ω 1/4W 1%
C5, C6: 0.01µF
Jumper: 0Ω 1/6W
J1: RJ45 socket
It is essential to remove the power converter, U1, and C11 and R22. Those components connect to 12V, and leaving any of them in place could put 12V on to an input to the DP83902. C11 also has to be removed to put in the 0Ω jumper, and C11 should be moved to the space for C13. U16, T2, and related components for coax don't need to be removed.
I borrowed a NuBus bracket from an Asante MCiNB, which fit perfectly, and the first card is converted and working great.
The conversion needs an RJ45 jack, 20F001 magnetics, 8 resistors, and 2 capacitors. Later revisions of the magnetics, 20F001N or 20F001NG, are available on eBay, everything else I got from Mouser:
R5, R14: 274Ω 1/4W 1%
R6, R10: 66.5Ω 1/4W 1%
R7: 806Ω 1/4W 1%
R12, R13: 49.9Ω 1/4W 1%
C5, C6: 0.01µF
Jumper: 0Ω 1/6W
J1: RJ45 socket
It is essential to remove the power converter, U1, and C11 and R22. Those components connect to 12V, and leaving any of them in place could put 12V on to an input to the DP83902. C11 also has to be removed to put in the 0Ω jumper, and C11 should be moved to the space for C13. U16, T2, and related components for coax don't need to be removed.
I borrowed a NuBus bracket from an Asante MCiNB, which fit perfectly, and the first card is converted and working great.
