OK, it appears there are 3 possibilities to check out : 1) The G7273 card is faulty and/or not making proper contact, and is thus not actually completing the NPG chain. 2) The device _before_ this slot (possibly the arbiter itself) can drive the input of the RX211 card, but can't drive the terminator. I have no idea if the latter is a significantly heavier load, but it might be!. 3) There is a problem before this slot (fault on the arbiter), which is genuinely asserting a grant signal, but the RX211 is getting into a state where it doesn't pass on grants, so said errant grant never gets to the M8302 to cause problems. Yet again I have to ask you to stop swapping cards around essentially at random, and to get out the test gear and make some measurements. With the G7273 card in, look at the grant lines at the teminator. Is one high? which one? Is it genuinely high, or marginal? What are the grant lines doing at the arbiter? All low as they should be? Can you get continuity along the grant chain with just G7273 cards in the machine? If not, why not? And so on. Actually get some evidence before trying to cure the fault. -tony