[sebhc] H89 diskette drive

Carroll Waddell carrollwaddell at sc.rr.com
Sun May 13 19:18:57 CDT 2007

I got my H89 CPU board repaired and working. I am having trouble with 
the diskette boot. When I enter B (ENTER) to boot from the primary, the 
drive runs for a few seconds then the screen says BOOT?
I have 2 diskette adapter boards, and I've tried them both. Same thing. 
I've tried different drives. Same thing. I have attempted to boot both 
CP/M and HDOS. Same thing. I'm sure my diskettes are ok because both 
HDOS and CP/M boot fine on my H8.
I connected my scope to the Read Data line coming from the drive. When I 
try to BOOT, there is activity on the READ DATA line. I checked the READ 
DATA going into the UART.
Different drives - Different diskette adapters - Different Diskettes - 
Different OS's. What am I missing?
I don't have much printed information about how this adapter works, and 
no troubleshooting procedures or waveforms that I can look at. I checked 
the rotational speed and it is correct.
Anyone have any ideas?
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