The Sinclair QL Forum

Some further uncovered info on the CST Q Disk from the pictures :

1) Under the cover of the Q Disc that has not visible heatsink is the regulator and heatsink - not sure which is the earlier model, but one has heatsink and reg on the side and one is under the plastic cover (on that one - there is nothing else except the disk drive connector)

2) Chips for the one in the picture 74LS240 - Octal 3 state buffer, 74LS124 Hex D type Flip Flop, 74Ls04 Quad NAND (with 8MHz xtal), 74LS03 Quad NAND OC, 74LS10 Triple 3 input NAND, 74LS2x6 (I could not see if this was an 8 or 6) Quad XNOR.

3) The Quad XNOR will decode the SP0-3 and A14-!7 address lines - when they are equal the interface is select (default as described in my last post) - the small transistor in the circuit will signal DMSC to disable the internal circuitry in the QL allowing this interface to take over - in conjunction with logic in 8) below

4) The 74LS04 chip and crystal provide the 8MHz clock to the disk interface chip (WD1770)

5) The 74LS240 chip buffers the disk interface signals to the connector and outside world

6) The 74LS174 probably provides the additional I/O port for drive number select

7) The ROM is only an 8K version - so the ROM / I/O split may be done simply using A13 line to select either the ROM or the I/O on the card

8) The other logic chips no doubt used to decode R/W, A18, A19, DS and provide DTACK back to the QL

nikosdoykas wrote:any schematics for this????

Why do you want a schematic? Has your board gone faulty? If so you might be able to fix it with a bit of thought about where the fault lies.

For whatever it's worth...

wow many thanks,,,, yeah

maybe some other have schematics for other disk controllers like cumana...

There’s only a need for two disk schematics, really. The Sandy SuperQBoard is the definitive WD177X controller, and the (S)GC is the definitive 8473V controller. The former provides SD/DD or DD/HD functionality, and the latter adds ED to the roster. All the OS capabilities are driver defined.

like cumana disk controler schematics?

As Dave said - they will be pretty similar to the way the other disk interfaces work - this is because the QL I/O expansion is well documented in the technical manuals which the various manufacturers have had to adhere to, and on top of that - the range of chips used in the disk interfaces were not that wide - for the most part based on the WD 177x series or the 8743 used in the Mircale Gold cards

yes i agree but actually will be nice to have the old hard ware schematics..... in one page... if exists of cource....

As there also was an QFLP Eprom from TT for the Medic boards: Does anyone knows, what kind of commands were used for the original Medic boards? What kind of software there was used?