[comp.sys.ibm.pc.hardware] HELP: What jumpers to make HP-VECTRA use 360K as A: ?

G.Moretti@massey.ac.nz (Giovanni Moretti) (06/13/91)

Hi

I've been resurrecting an HP Vectra (serial Prefix 2716A - no it's not
an EPROM :-) and seem to be having some success however I'd like to
install a 360K disk as drive A (no drive B, there isn't room).  In the
HP service manual it states that the machine can be made to work with
ANY COMBINATION OF 1.2MB OR 360K DRIVES for drives A: and B: but nothing
I can do will convince it to work with the 360K drives - they turn on
and act normally but always give "NON-BOOT DISK OR DISK ERROR" message.

I can start the PC up then using SETUP tell the PC that it has 1.2MB
drive as drive A and a 360K drive as B: - drive A works fine, I can boot
off it and everything but the 360K never reads correctly.

In the section of the manual on installing floppies it gives the correct
motherboard jumper layout for 1.2MB drives but doesn't mention 360Ks at
all.

The jumpers (when set as per the manual for 1.2MB) look like:

(I'll use 0 0-0  to indicate a row of three where pins 2&3 are connected
 and pin 1 stands alone)
------------------------------------------------------------------------
                BACK of MOTHERBOARD
NOT TO SCALE                           JU1
                                        8   <--  Top 2 of three connected
                                        o
                JU2
                 8
                 o
                              JU5   For 1.2MB drive
                               o       Bottom two connected if serial#
                               8       Prefix >= 2712A, top two if <2712A
                                    Doesn't say whether this is for A: or B:
                                        WHAT ABOUT 360K?
           JU3                  JU4
      EE   8 8  E3              o-o
      EC   8 8  E2
      EO   o o  E1
---------------------------------------------------------------------------
     Top pair of each    From FIG 3.16          This is the Edge of the
     column jumpered     Vectra Service         motherboard at the front of
                            Manual              the PC

How do you make it so it will:

     (a) Read 360K disks at all?

     (b) Boot from a 360K disk using it as drive A:
         (preferably even WITHOUT THE BATTERY
          ie irrespective of the CMOS contents)

     (c) How does it know whether drive A or B are what density - it it
         totally done by the CMOS setup or ARE THERE JUMPERS FOR THE BOOT
         FLOPPY?

     (d) What sort of batteries do I install? (the battery pack is missing).
         It looks like four penlites (AA) should be about right and there
         doesn't seem to be any voltage on the pins to the batteries which
         implies that they're NOT rechargable. Is this correct?


It's actually a lovely machine, it was donated because of a very
intermittent memory fault (only every once in a long while) but I can't
make it fall over.

The 1.2MB drive I'm currently using is only on loan :-( so once I can
make it boot from a 360K disk (and remember it's setup), I can start
using it :-)

Any help would be very much appreciated.

Thanks
Giovanni

-- 
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Giovanni Moretti, Computer Science Dept, Massey University, Palmerston North,
Mail: Internet: G.Moretti@massey.ac.nz, Pkt-Radio: ZL2BOI@ZL2TCA | New Zealand
Ph 64 63 69099 x8694,FAX 64 63 505607 | QUITTERS NEVER WIN, WINNERS NEVER QUIT
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