Re: I'm a newbie all over again..!

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <452174360wnr@klatch.demon.co.uk>,
John Le Febvre  <John@klatch.demon.co.uk> wrote:
> 
> There is a very small 'patch board' on the lower right of the m/b
> (towards the front).  Anyone know what it's for?  Just curious...

(See Dave Althoff's post for some ideas.)

If you mean the left of the board, there is a set of burn-in pads
labelled J23.  This is a connector for diagnostic hardware that is
used to test motherboards during the manufacturing process.

In the lower right there is a 7-pin molex connector (J25), between the
Ensoniq chip and the RAM slot.  This is the sound expansion connector.

Where is this "patch board" relative to the molex connector?

> I put my Rev.C SCSI into slot 7 ("Your Slot") and it wouldn't
> recognize the drive.  When I dropped to BASIC and typed PR#7, the
> screen changed to 40 cols and the cursor appeared at the bottom.
> No messages or anything.  If I set the startup slot to slot 7, I
> got 'Check Startup Device'.  Any ideas, anyone?  Looks like I may
> have to order that RamFast early... ;)

It doesn't think you have any hard drives connected.  The above
behaviour is normal.  PR#7 will just drop out to BASIC if there is no
boot device.  A slot-scan boot will resume booting at the next slot.

Obvious things to check:

- SCSI ID: the Apple SCSI card should have a single jumper, in the
  rearmost position (ID 7).  The drive must be set to an ID other than 7.

- Termination.  You must have termination after the drive, assuming it is
  the only device (either internal termination in this drive, or a clip-on
  external terminator).

  If you have more than one SCSI device, you need TWO terminators with the
  original Apple card, because the card doesn't have its own termination.
  The first and last SCSI device should be terminated (the first one
  should ideally be a pass-through terminator connected between the SCSI
  card and drive).

> Talking of power supplies, is the //e power connector at a different
> watt rating than the normal gs connector?

I don't think so.  The power supplies have the same wattage, but
different voltage balances (the IIgs motherboard needs more current
on the 5V rail than the IIe, but less on the 12V rail).

> I guess I could do with knowing the pinouts of all the
> connectors on the board, as I have no docs whatsoever.  What are the
> compatabilities between say Apple II and Mac PSU's?

The pinouts are all covered in the IIgs Hardware Reference, which is
not available any more.

I doubt that Mac supplies would be compatible.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand