The Sinclair QL Forum

Thanks to Skagon for pointing me in the direction of retroclinic.com - it looks as though WD1772 chips are still available out there (well the VL1772) - although he had to buy 250 last time he bought some.

Cost is around $8 USD per chip (plus import duties, VAT and postage and the handling charge for the import duty and VAT) - so works out at about $10 USD per chip

Would be hard to justify this many unless someone does come up with a new disk interface (although the excess stock could of course then be sold for other retro machines)....

Mark of retroclinic pointed me to 2 dealers he has used:

http://www.bermanelectronic.com/

and

http://www.utsource.net/VL1772.html

Also see this seller

Mark

Any ideas on what the extra letters are after the 1770 or 1772 - the ones in the Trump Card do not have letters after them so far as I recall.

I know you have to be careful with some of the early interfaces - I had a couple where the 1770 chip had failed - I tried replacing it with a 1772 chip from a Trump Card, and they would not even initialise - presumably due to timing differences.

IIRC the 1770 and 1772 have different step rates, the 1772 being more suitable for 3½ drives.

The WD1772-PH02-02 is a faster rated WD1772 so on machines that can handle faster disk transfers, you can feed in a faster clock signal to the WD1772 and can then read and write to HD disks in a HD FDD

I cannot find my copy of a data sheet ATM, but these Atari Wiki pages contain some info:-
Programming information for the Western Digital 1770-00 and 1772-00 floppy disk drive controllers
WD1770/1772 5 1/4 " Floppy Disk Controller/Formatter

Mark

The P means plastic DIP package, the H means 28 lead / pin package.

Data sheet for the WD1772-02 here

Also here is an edited version

See also:-
http://www.datasheetarchive.com/WD1770-datasheet.html
http://www.datasheetarchive.com/WD1772-datasheet.html

Mark