[sebhc] H89 Diskette Trouble

Carroll Waddell carrollwaddell at sc.rr.com
Mon May 14 12:32:38 CDT 2007

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.

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