R
Roni Leben
Guest
Hi,
I am trying to debug an old proprietary computer (embroidering machine
control).
The symptom is non working FDD.
I found an interesting thread about FDD drives on sci.electronics.design
newsgroup:
http://www.electronics-forum.net/design/Floppy_disk_MFM_data_separator_design_341430.html
The computer has a CPU board, a video board (Hercules I think), EEPROM
board, interface boards for axis actuator controllers, PSU boards,... about
10 boards altogether and dates back to late '80s.
The machine has two FDDs connected in parallel (master/slave determined by
jumpers) - they seem to be normal 3.5" HD PC type units.
Since everything else seems OK (computer boots up normally), the error
should be somewhere in the CPU - FDD link.
The FDC1797 was running very hot, so it was replaced (after >3w waiting and
paying ~100 EUR to discontinued parts dealer), but the thing still does not
work. The FDD light is on for about 5 seconds, but the floppy cannot be
read. I think the spindle motor is running, not sure if there is any head
movement (to much environment noise, will have to dismantle the machine to
remove FDD units).
Flat cable is OK, remaining suspects are FDC9216B (data separator I think),
two 7406N and one 74HC163. I will check the standard logic parts today, but
don't know what to do with FDC9216B - I do not want to pay premium price
(and wait a few weeks) for discontinued part again, just to find out the
device still does not work.
Any idea on how to find if the culprit is FDC9216B? A datasheet would
certainly help...
Thanks and BR
Roni
I am trying to debug an old proprietary computer (embroidering machine
control).
The symptom is non working FDD.
I found an interesting thread about FDD drives on sci.electronics.design
newsgroup:
http://www.electronics-forum.net/design/Floppy_disk_MFM_data_separator_design_341430.html
The computer has a CPU board, a video board (Hercules I think), EEPROM
board, interface boards for axis actuator controllers, PSU boards,... about
10 boards altogether and dates back to late '80s.
The machine has two FDDs connected in parallel (master/slave determined by
jumpers) - they seem to be normal 3.5" HD PC type units.
Since everything else seems OK (computer boots up normally), the error
should be somewhere in the CPU - FDD link.
The FDC1797 was running very hot, so it was replaced (after >3w waiting and
paying ~100 EUR to discontinued parts dealer), but the thing still does not
work. The FDD light is on for about 5 seconds, but the floppy cannot be
read. I think the spindle motor is running, not sure if there is any head
movement (to much environment noise, will have to dismantle the machine to
remove FDD units).
Flat cable is OK, remaining suspects are FDC9216B (data separator I think),
two 7406N and one 74HC163. I will check the standard logic parts today, but
don't know what to do with FDC9216B - I do not want to pay premium price
(and wait a few weeks) for discontinued part again, just to find out the
device still does not work.
Any idea on how to find if the culprit is FDC9216B? A datasheet would
certainly help...
Thanks and BR
Roni