840av nubus slot A works, but makes the system unstable...

[lobust]

As per title, nubus slot A (the one with the inline DAV slot) works superficially, but attempting to use functions of a card installed in that slot freezes the system in pretty short order.

Tested so far with three scsi cards (SEII, SEIV, Jackhammer) as those are what I have on hand. All exhibit similar behavour, they work normally, but very unstable. Failure mode is a soft system freeze that can be rebooted with command-ctrl-power.

All three cards work perfectly fine in slot B.

Anyone know of any common faults that might cause these symptoms?

 

[Byrd]

Have you deep cleaned the slot and checked for any socket damage close up?

 

[tjjq44]

Maybe dammage caused by old capacitors leaking (even if recap is already done)

 

[lobust]

Have you deep cleaned the slot and checked for any socket damage close up?

Maybe dammage caused by old capacitors leaking (even if recap is already done)

I have recapped and cleaned the board. The connector is in good condition. There were only a couple of broken traces on this one, none near the nubus section, cap damage on the lower half of the board was extremely minimal.

I have an update too - it is only SCSI cards that are unhappy in this slot, I have just spent the last hour (not too aggressively) stress testing a couple of Thunder/24 and Thunder II video cards in this slot - 1152x864, millions of colours, browsing Macintosh Garden with Netscape Navigator 3.01, playing couple of games etc.

The video cards, as best as I can tell, are working perfectly in this slot.

The jackhammer manual says to put the card in the "left hand" slots ideally, but it doesn't say why and stops short of saying that the top slot has any compatibility issues.

The silicon express manual says nothing pertinent at all.