Xebec Card Help

[Jeff.Brielmaier@juge.com (Jeff Brielmaier)]

b >For a while now, I have had a Xebec card in my discard/junk box. I had
b >assumed that the card was non-functional because one of the connector pins
b >was broken off. I have just read  that sometimes owners cut off pin 25 to
b >prevent some kind of termination power problem with some hard drives. This
b >is the pin that is broken on my card.
b >
b >Can someone explain to me exactly what removing pin 25 is supposed to do?
b >I would also like to know what types of hard drives (SASI/SCSI) can be
b >attached to this card.

The original SCSI spec placed the "Terminator Power" (+5V) and Ground pins 
[pins 25 & 26].  If (when?) a user plugs the SCSI ribbon cable upside down, 
5 volts is shorted directly to ground [not a good thing <g>].

So, by clipping the pin on the controller card Xebec (dba First Class 
Peripherals) prevented a number of customer problems [generally melting the 
SCSI cable straight down the middle].

b >On another item with this Xebec card, there looks to have been a
b >modification to this card. I believe that there is a different ROM chip
b >installed from what was originally used. The current ROM is labeled:
b >
b >Micromux
b >Rev A (c)1986
b >Johnson Assoc.
b >Read/Write & STD
b >
b >Attached to the ROM are two wires that end in a small toggle switch. There
b >is a label on the wires which reads:
b >
b >Switch in R/W position toward slot (Red Dot)
b >Switch in STD position away from slot
b >
b >Any help with this would be appreciated.

Micromux was a 3rd party add-on (non-Xebec/FCP) that allowed multiple Sider 
controller cards to be connected to an interface box which was connected to 
the Sider hard drive.  The add-on box, which you can probably guess, allowed 
multiple Apple //'s to share a single hard drive.

 * KingQWK 1.05 # [PK] * Taxation WITH representation isn't so hot, either.