Search found 208 matches

by Silvester
Tue Oct 08, 2019 1:09 pm
Forum: Hardware
Topic: Today I received...
Replies: 2
Views: 316

Re: Today I received...

I wonder if the eBay seller could find anything more to generate static electricity to zap them. (A Van-der-Graf generator won't fit in the bag.) ! :lol: Some of the ICs I get from china are packaged the same. I guess the real problem only arises with a potential between the pins destroying (or wor...
by Silvester
Sat Sep 28, 2019 9:22 am
Forum: Hardware
Topic: DIY Fpu Unit for STFM
Replies: 28
Views: 3795

Re: 74HCxx vs 74LSxx

The red CPU sockets Sinclair used in QLs are really terrible. They will not reliably support any sort of daughter card at all. More than half of the problems with intyernal memories that used that socket were because of the socket. It would definitely be more reliable (and easier!) to put the CPU a...
by Silvester
Wed Sep 25, 2019 2:38 pm
Forum: Wanted
Topic: Assembler for the ql
Replies: 10
Views: 587

Re: Assembler for the ql

The manual was available from within the program as a Help file. But the zip file (link above) contains a separate printable version of the manual.
by Silvester
Wed Sep 25, 2019 2:28 pm
Forum: Wanted
Topic: Assembler for the ql
Replies: 10
Views: 587

Re: Assembler for the ql

Have a look at Talents Assembler Workbench http://www.dilwyn.me.uk/asm/talentaw22.zip
by Silvester
Tue Sep 17, 2019 12:59 pm
Forum: Wanted
Topic: Schon keyboard
Replies: 10
Views: 834

Re: Schon keyboard

I replaced the flakey QL membrane keyboard connecter with turned pin sockets. Also replacing Schon lead with a ribbon cable soldered into turned pins, improving reliability. One of the problems with replicating Schon QL keyboard was the fact Schon supplied a very neatly cut out QL top case (along wi...
by Silvester
Sat Sep 07, 2019 9:27 am
Forum: Wanted
Topic: Schon keyboard
Replies: 10
Views: 834

Re: Schon keyboard

Sorry to be contrary, but I have both the PS and the QL Schon keyboards, bought them back in early 1990's and they still are in use today. The PS keyboard has had several cleans of the PCB before eventually the carbon key pads wore thin. Solution was to (painstakingly) stick foil contacts on them (a...
by Silvester
Thu Aug 15, 2019 12:48 pm
Forum: Hardware
Topic: Mod on ULA
Replies: 9
Views: 1228

Re: Mod on ULA

Bit of a coincicdence :-) I recently resurrected an old QL motherboard which I had removed the 33k resistors from the ULA (not required when I used QIMI). With no microdrives attached (and no QIMI) I sometimes had trouble getting the cursor to appear after pressing F1/F2. But then I noticed if I wav...
by Silvester
Sat May 25, 2019 9:31 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5657

Re: Asymmetric multiprocessing...

But that can be better done with fast SERial 68681 (one of the reasons why I'm doing it); 31250 MIDI option with opto-isolators along with full SER. You'd have to change the crystal to get the right baud rate out of the 68681, so you would need to use a separate 68681 for MIDI and for serial. If th...
by Silvester
Tue May 21, 2019 3:24 pm
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5657

Re: Asymmetric multiprocessing...

Oh that reminds me, when I first tried the MIDI interface with a Gold card it was double stepping (as each byte of Z80 code is uploaded it should 'read' back an incrementing address number). Thinking it may be due to GC 68000 not having A0 and it was doing a word access I did a quick remedy by swapp...
by Silvester
Tue May 21, 2019 3:05 pm
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 5657

Re: Asymmetric multiprocessing...

Dave wrote: Have you worked out a schematic, or got clear photos of the MIDI board?. It sounds like it would be a very interesting thing to see. Hmm, the schematic was in http://www.dilwyn.me.uk/docs/hardware/QLperip.zip (was I wot did it). Dave wrote: MIDI has been whispered in my ear more than a ...