Search found 624 matches

by Pr0f
Sat Jun 13, 2020 10:39 pm
Forum: The Off-Topic Section
Topic: Happy Birthday!
Replies: 267
Views: 81619

Re: Happy Birthday!

Happy Birthday :-)
by Pr0f
Sat Jun 13, 2020 7:32 pm
Forum: Hardware
Topic: Boot Q68 without monitor and keyboard
Replies: 21
Views: 1234

Re: Boot Q68 without monitor and keyboard

that's 3 customers already! :-)
by Pr0f
Sat Jun 13, 2020 9:58 am
Forum: Hardware
Topic: Boot Q68 without monitor and keyboard
Replies: 21
Views: 1234

Re: Boot Q68 without monitor and keyboard

It looks like you would have to add analogue to digital devices to it to make those available, as that looks like one of those amazing Lattice FPGA's with small footprint and packing a hell of a lot of logic capability and RAM on chip - I spot a micro SD card and what looks to be 2 RAM devices. I ha...
by Pr0f
Thu Jun 11, 2020 12:23 pm
Forum: The Off-Topic Section
Topic: Norm's New Book - 55% Off!
Replies: 50
Views: 2684

Re: Norm's New Book - 55% Off!

i think the difference between assembler and basic is that you are directly responsible for the commands being run when programming in assembler - as you've provided the instructions - with Basic - there is a lot going on behind the scense, so sometimes the unexpected can happen. Also - Assembler is...
by Pr0f
Thu Jun 11, 2020 7:54 am
Forum: Hardware
Topic: Issue 6 VM12 & resistors confusion
Replies: 79
Views: 4174

Re: Issue 6 VM12 & resistors confusion

I've seen boards with 150ns and 120ns chips in - so 120ns should be fine. I've more often than not needed to put a dab of new solder on to 'free up' the existing stuff. Also - it pays to carefully bend up the leg with a pair of fine tweezers or a scalpal blade, once the solder is flowing - normally ...
by Pr0f
Wed Jun 10, 2020 1:55 pm
Forum: The Off-Topic Section
Topic: Norm's New Book - 55% Off!
Replies: 50
Views: 2684

Re: Norm's New Book - 55% Off!

Ordered my copy today too :-)
by Pr0f
Wed Jun 10, 2020 8:01 am
Forum: Hardware
Topic: Boot Q68 without monitor and keyboard
Replies: 21
Views: 1234

Re: Boot Q68 without monitor and keyboard

how about a small 8 pin PIC pretending to be a keyboard - that would probably work...
by Pr0f
Tue Jun 09, 2020 2:44 pm
Forum: Hardware
Topic: Issue 6 VM12 & resistors confusion
Replies: 79
Views: 4174

Re: Issue 6 VM12 & resistors confusion

I looked at doing that - you could put SRAM in one of the ROM sockets and wire the missing address lines to give you static ram in the address map - but you need to make RAM available for the ZX8301 which is producing the video display - and that's engineering to work with Dynamic RAM - fast page mo...
by Pr0f
Mon Jun 08, 2020 7:13 pm
Forum: Hardware
Topic: Issue 6 VM12 & resistors confusion
Replies: 79
Views: 4174

Re: Issue 6 VM12 & resistors confusion

oooh - purple ceramic goodness :-)
by Pr0f
Mon Jun 08, 2020 11:32 am
Forum: Hardware
Topic: QL Video issue - Red color missing
Replies: 16
Views: 3474

Re: QL Video issue - Red color missing

For static it makes little difference - as the voltages are that much higher, but the danger of a lower voltage zener is it starts to conduct a little before it's rated zener voltage The idea is to try and prevent too much voltage at the chip pins to avoid the parasitic diodes / thyristors and goodn...