Search found 2771 matches

by Dave
Sun Apr 21, 2024 9:07 pm
Forum: Hardware
Topic: SOLVED ntsc sinclar ql schematics ??
Replies: 15
Views: 1329

Re: ntsc sinclar ql schematics ??

Exact UK layout no changes.
by Dave
Sun Apr 21, 2024 6:40 pm
Forum: Hardware
Topic: SOLVED ntsc sinclar ql schematics ??
Replies: 15
Views: 1329

Re: ntsc sinclar ql schematics ??

The only changes to the US QL from the German QL are: US modulator/filters/xtal and modest component value changes around MC1377. A bodge board glued on the RAM from the clock crystal that passes the clock through two inverting gates to buffer and clean it up a bit. This gets the clock much closer t...
by Dave
Tue Apr 16, 2024 10:26 pm
Forum: Hardware
Topic: PiStorm
Replies: 147
Views: 27689

Re: PiStorm

The Pi would always be too tall to fit inside the BBQL except within the expansion slot. I have a customer Pi-based board using a CM4 that is 9mm tall at its highest point. Everything in PiStorm can fit on a baseboard with a CM3. A CM4 (if PiStorm supports Pi4 yet) would be 0.7mm slimmer. So a PiSt...
by Dave
Sun Apr 14, 2024 6:07 pm
Forum: Hardware
Topic: PiStorm
Replies: 147
Views: 27689

Re: PiStorm

Stupid question, but how is an emulated processor on a real QL going to be better than an emulated processor in sQLux or similar? Since the emulated Io is superior to genuine IO in every way, couldn't we just make a QL-fitting carrier board for a CM4 for the QL case?
by Dave
Thu Apr 11, 2024 7:04 am
Forum: Hardware
Topic: 4864 DRAM
Replies: 5
Views: 2115

Re: 4864 DRAM

I dug through my notes and found the following: D06- had NEC UPD4164C-3 (seen once) D06- had Hitachi HM4864P2 D09- had Siemens HYB4164P2 D09- had TI TMS4164-15NL (most common) D09- had Mostek MK4564-15 S18- had TI TMS4164-12NL Others I haven't seen but listed in the service manual include MCM6665AP1...
by Dave
Tue Apr 09, 2024 11:10 pm
Forum: Prospective Members
Topic: Alas...
Replies: 0
Views: 955

Alas...

I think we can lay this one to rest now.
by Dave
Tue Apr 09, 2024 10:35 pm
Forum: Hardware
Topic: Switching Regulator?
Replies: 37
Views: 5166

Re: Switching Regulator?

Interesting conversation to catch up on. 7805 is a very inefficient analog regulator and that inefficiency comes out as heat. Often 60-70% efficient, depending on the input/output voltage. Buck regulators are switching 'digital' regulators [1] that make a lot of switching noise but are very efficien...
by Dave
Tue Apr 09, 2024 9:56 pm
Forum: Hardware
Topic: Serial port confusion.
Replies: 18
Views: 5661

Re: Serial port confusion.

Actually, Sinclair's solution was a good idea of having a DTE and a DCE configured serial port because it avoids having an external NULL modem gender changer because the conversion is builtin to the QL. They made up for it with the bad idea that received information from both sockets goes to a sing...
by Dave
Tue Apr 09, 2024 9:52 pm
Forum: Hardware
Topic: FPGA replacment for the ZX8301 ULA and more
Replies: 267
Views: 105395

Re: FPGA replacment for the ZX8301 ULA and more

Yeah, those red sockets are junk. I have had to replace dozens of them as they often fall apart if the CPU is stuck in them. Any time I installed an internal memory expansion in a QL at Sandy and it had a red socket, I'd fire up the weller first just in case. On my multitude of QLs, if I see a red s...
by Dave
Tue Apr 09, 2024 9:13 pm
Forum: Hardware
Topic: PiStorm
Replies: 147
Views: 27689

Re: PiStorm

The PiStorm signal transitions are incredibly quick, and play absolute mayhem with the QL. The PiStorm can function in a Gold Card if the onboard DRAM is removed and the refresh signal used by INGOT is inhibited. However, external signals would need conditioning to reduce their slew rate. The SGC cl...