Denton Gentry wrote:

>   Ok, I'm a moron. I tried to attach a backpack style case for
>   2.5" SCSI drives to my SE/30. The backpack gets its power
>   from the ADB port. I managed to fry the ADB chip on my
>   motherboard doing this.
> 
>   Now when it boots the LEDs on the keyboard do not flash
>   like they used to. The mouse does not move the cursor in
>   the MacOS screen. The keyboard and mouse work properly on my
>   other Macintosh (PB 540), so I am sure they are ok and the SE/30
>   is not. I now measure 1.2 volts across the ADB power pins,
>   I assume that should be 5 volts.

Denny,
There is a transistor on the output of the ADB chip on the
SE/30. I don't know what the Q# is, but it's a 2N3904. You
might want to check if this transistor is fried or shorted before 
buying a whole new board. I don't know whether these normally
die, but it's worth a shot. If it was just the ADB chip that is
fried, I don't know why the power pin would be at < 5V without
affecting other chips on the motherboard.

Also, some boards have a fuse on the +5v line. But I don't
think the SE/30 does. Plus, there is a voltage on the power
pins, so the fuse is probably not 

You might also want to give MicroDoc a call. They repair 
Mac motherboards. About $120 for a SE/30 I think. They also
sell individual Mac-specific chips that you can't find
elsewhere. (I think many are used chips they've removed off
of otherwise busted Macs) I don't know if they specifically
have any ADB chips, but you could ask. Their number is
541-344-5335. (FYI: This is the company that Mike from the
CAEN shop used to repair boards that were out of warranty)

	--John