By swapping in a 6530 from a CBM 4040 drive, I confirmed a bad 6530 in the SFD1001. With the substitute chip it passes the performance test diagnostic. Encouraged by that I ordered a board based on Ruud's design to use a 6532 replacement. For the first round I programmed the 1k binary image of 251257-02A.bin into the top 1k of a 2764 EPROM. The drive gives 5 flashes (same as the original symptoms). Next, I burned a 2764 with the 1k image repeated eight times. The drive would now initialize and seems to read data - at least I can load and run "performance test" from the SFD diagnostics diskette. However, the test fails at the first step (format scratch diskette). Similarly I am unable to format diskettes from CBM Basic using 'HEADER"NAME",U8,D0,I42'. In either case, it recalibrates to track 0 and just sits there with no head step, eventually timing out with a disk error. I have tried three or four diskettes that all worked with the replacement 6530. No luck at all. Does anyone have advice for the next troubleshooting step to take? Is something different needed on the EPROM? -- Sent from: http://cbm-hackers.2304266.n4.nabble.com/Received on 2020-05-31 21:00:02
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