Floppy Disk Problem on HP/Agilent Logic Analyzer

Hi together,

two months ago the floppy disk drive of my HP/Agilent 1661A analyer stopped working: One always gets CRC ERROR or BAD DISK. This makes the analyzer rather unusable since it is not real fun to reenter the labels etc on each usage...

So I tried to fix it: The floppy disk drive is of type EPSON SMD1000, Serial N1405001, SupType SMD1040-018, C30601. I got four SMD1000 drives via eBay and I had to notice that there exist many different versions of them:

Most originate from laptops and have a 26 pin flexible connection for shugart bus and power. The drive from the analyzer has the PC standard pinheader with 34pins but also contains power on this pinheader. The standard pinouts are readily available on the WWW and I figured out how power is passed to the SMD1000 in case of the HP1661A analyzer (7, 9, 11: +5V, NOT GND as usual ->

short circuit if normal PC drive is connected). So I tried another EPSON SMD1000 haveing the pinheader first. Result: Does not work, too!

So I suspected the FDC beeing the problem and I changed the WD37C65C and verified the crystals etc. for proper operation. This did not improve the situation. A new cable did not change anything either. So ???

Recently I noticed that additionally to the jumpers on the drives (which I set properly, of course) there is a short piece of flexible PCB which is used as a 7-flod jumper within the drive. But these PCBs are different in the drives. Within the 5 drives I have, there are tree different PCBs (Type A (2-3 and 5-11), Type B (2-3, 4-14 and 7-8-11) and Type L from the analyzer (3-13, 4-12 and 5-9-11)). They change some internal connections and deliver signals to undocumented pins of the pinheader, too.

Now my questions are: (1) Has anyone out there experience with changing the floppy on the HP1660 analyzer series? (2) Does there exist documentation on the EPSON SMD1000 drive describing the meaning of the flexible PCB? I already contacted Epson without success. No, moving the flexible PCB to one of the other drives does not fix the problem. (3) Has anyone got documentation about the HP1660 analyzer series telling someting about the floppies? (4) I could build a adapter cable to connect one of the drives needing the flexible notebook connection to the analyzer but I suspect it does not make things better? (5) Connecting a PC-drive with seperate power (and of course disconnecting the analyzers power pins) always leads to error "TIMEOUT" independent of drive select jumpering. So I suspect that some kind of ready or disk inserted signal is missing - maybe this is related to the undocumented signals mentioned above?

Any hints are welcome,


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Erik Baigar
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