[sebhc] H89 Diskette Trouble

Stanley Webb spamspike at comcast.net
Wed May 16 06:18:59 CDT 2007

On May 16, 2007 Stan Webb replied:

A couple of things come to mind, (please forgive me if I'm stating  
the obvious):

I am most familiar with HDOS 2.0, so i'll assume that's the Boot disk  
you're using.  If the diskette step rate the driver on the boot disk  
is using is too low for the drive, I believe the disk won't boot. The  
Siemens drive in my original Z89 wouldn't reliably step faster than  
about 16-18 milliseconds. The pair of double sided 40 track Mitsumi  
drives I installed later stepped much faster and of course I set the  
step rate lower for greater speed.  The default step rate on the HDOS  
distribution that came with my computer was 30 ms.

I believe you should also be sure the drive itself is jumpered to be  
drive 0, since otherwise it would not send data.

You didn't say how many sides or number of tracks were on the Boot  
Disks you are using, but I am quite sure a double sided Boot diskette  
will not boot in a single sided drive and an 80 track diskette would  
not boot either in a 40 track drive like the Siemens drive that came  
with my Z89.

You might try pressing the space key a few times, just in case the  
baud rate recorded in the boot track of your Boot disk is different  
than that of the H89 you are trying to resurrect.

Your CPU logic board switch is set in default configuration, 9600  
Baud (POS 6&7 set 0)
My Z89 Operation manual also says this:


Terminal Logic Circuit Board
Switch S402 the switches on S402 are set at the factory to "0".
Switch S401 is preset for:
MODE          Switch Selector
                        0 1 2 3  4 5 6 7
9600 Baud      0 0 1 1
No parity                       0
Even parity                      0
Normal parity                      0
Full Duplex                            1

... Heath Software does not check parity ...

CPU Logic Circuit Board
Programming Jumpers
The programming jumpers JJ505 through JJ508 are determined by the  
types of location of the system PROM's. Be sure the jumpers are  
installed as follows:
Jumper       Location
JJ506            0
JJ507            0
JJ505            0
JJ508            B

Serial Interface

Refer to Pictorial 5-2 (Illustration Booklet, page 4 and set all  
three programming jumpers to OFF if this has not already been done.

end quote/

I notice these Jumper numbers are somewhat different than yours

I have 2 Z89's I can further examine if you think I might be able to  
help you.

On May 14, 2007, at 11:32 AM, Carroll Waddell wrote:

> I haven't been able to find out the problem with my diskette drive  
> yet. I feel like I have a problem with the configuration of the CPU  
> board rather than an actual hardware problem. Let me list what I  
> have on the CPU board. If someone has a working H89, can you look  
> and tell me what configuration you have.
> Have the hard sector controller card.
> The diskettes I'm trying to boot (1 is CP/M and the other is HDOS)  
> will boot fine on my H8.
> The CPU board is the new(er) one, part number 85-2549-1.
> U518 -    444-62    (MTR89)
> U516 -   444-41
> U520 -   444-19
> U517 -   444 66
> U550 -   555-61
> There are disk RAM chips in U523 & 525 (2114)
> There is an HDOS ROM at U520  (444-19)
> U562 is a 74S132.
> I have 64K memory.  (has the 16K memory expansion board)
> Memory test runs fine.
> JJ501 - 1
> JJ502 - 1
> JJ503 - B
> JJ504 - 0
> JJ505 - 0
> JJ506 - 0
> JJ507 - B
> DIP switch 501 is set as:
> POS   0 1 2 3 4 5 6 7
> SET   0 0 0 0 0 1 0 0
> 1. Memory test works ok
> 2. Rotational speed test works ok
> 3. When try to BOOT, drive becomes active for a few seconds then  
> screen says  BOOT?
> The configuration guide speaks of a WRITE PROTECT PULLUP. It says  
> this resistor is on the hard sectored controller card. What does  
> this do?
> I know on the H8 the diskette controller ROM and the diskette  
> controller RAM chips are removed from the board when you have XCON8  
> ROM and 64K.
> Should the HDOS ROM and RAM chips be on the CPU board?
> Any ideas would be appreciated.
> Carroll
> --
> Delivered by the SEBHC Mailing List

Delivered by the SEBHC Mailing List

More information about the Sebhc mailing list