23-12-2012, 10:42 AM
Many years ago, when I was a nipper, I was the proud owner of a +3. The built in floppy drive was for its time the mutts nuts. A couple of months ago I managed to obtain a (mostly) working example for my son who is discovering the joys of computer programming. With the BBC B still on the "what's the blasted hell wrong with it" pile and a lack of interest from me I decided to tackle the Sinclair.
Externally, in good nick apart from a scrape on top of the FDD housing, the inside was reasonably clean and tidy with no fluff balls. One rubber foot missing, not too serious. Needed a new power lead as the cable had frayed where it entered the PSU case, one from stock eliminated that problem. Powered up ok, brains intact and memory present in both personalities, put a floppy disk in and..... nothing.
The FDDs are made by Panasonic, and use a belt to drive the floppy rather than direct drive in more modern appliances. You also stand more chance of obtaining a bucket of rocking horse manure than obtaining a new drive so fixing was the only option. Belts are available from Ebay, they took a couple of days to arrive. Taking apart the drive is fiddly but there is an excellent guide from dataserve-retro.co.uk that goes through the process. The remains of the belt were found in a sticky mess wrapped around the drive motor capstan and this had to be removed with a cotten bud soaked in alcohol. Fitment of the belt was easy, just a stretch around the two pullys and wullah, all done. One note of warning, if you turn the drive upside down the R/W pin falls out and can be lost easily.
So, testing again, I could now read pre-formatted disks but when I tried to format a brand new blank the drive was reporting errors. I know the heads were cleaned but I gave them another pass with the cleaner and the same result. The last time I had a +3 I had a utility called Disk Doctor for recovering duff or awkward disks. £4 obtained me a copy, again from dataserve, and it was quite happily recovering the disks for use. All I can think of is that over 25 years the disks lost their low level formatting and disk doctor refreshed the markers. One other fix, a new 3.5" stereo tape socket and all was well.
Dennis has picked up for me my next patient, a Sinclair+ computer with a somewhat dicey keyboard. Looking forward to resurrecting the computer very soon.
Externally, in good nick apart from a scrape on top of the FDD housing, the inside was reasonably clean and tidy with no fluff balls. One rubber foot missing, not too serious. Needed a new power lead as the cable had frayed where it entered the PSU case, one from stock eliminated that problem. Powered up ok, brains intact and memory present in both personalities, put a floppy disk in and..... nothing.
The FDDs are made by Panasonic, and use a belt to drive the floppy rather than direct drive in more modern appliances. You also stand more chance of obtaining a bucket of rocking horse manure than obtaining a new drive so fixing was the only option. Belts are available from Ebay, they took a couple of days to arrive. Taking apart the drive is fiddly but there is an excellent guide from dataserve-retro.co.uk that goes through the process. The remains of the belt were found in a sticky mess wrapped around the drive motor capstan and this had to be removed with a cotten bud soaked in alcohol. Fitment of the belt was easy, just a stretch around the two pullys and wullah, all done. One note of warning, if you turn the drive upside down the R/W pin falls out and can be lost easily.
So, testing again, I could now read pre-formatted disks but when I tried to format a brand new blank the drive was reporting errors. I know the heads were cleaned but I gave them another pass with the cleaner and the same result. The last time I had a +3 I had a utility called Disk Doctor for recovering duff or awkward disks. £4 obtained me a copy, again from dataserve, and it was quite happily recovering the disks for use. All I can think of is that over 25 years the disks lost their low level formatting and disk doctor refreshed the markers. One other fix, a new 3.5" stereo tape socket and all was well.
Dennis has picked up for me my next patient, a Sinclair+ computer with a somewhat dicey keyboard. Looking forward to resurrecting the computer very soon.