Search found 2758 matches

by Dave
Sun Feb 26, 2023 2:10 pm
Forum: For Sale
Topic: Tetroid TDI 1, Power Regulators and ROM Switchers ALL SOLD
Replies: 12
Views: 10421

Re: Tetroid TDI 1, Power Regulators and ROM Switchers

It’s amazing the lengths some people will go to for beer money!
by Dave
Sun Feb 26, 2023 6:51 am
Forum: Hardware
Topic: My QXT640 thread
Replies: 22
Views: 3690

Re: My QXT640 thread

Let’s add to this family picture.
by Dave
Sat Feb 25, 2023 5:17 pm
Forum: Compatibles Corner
Topic: CST THOR 20 2F
Replies: 9
Views: 5587

Re: CST THOR 20 2F

The batteries start leaking because of a chemical process. When discharged, the contents expand compared to new state. Containing a paste with a liquid electrolyte, the electrolyte is the only thing that can move and is forced out. Even if you see no signs of leakage, there can still be some electro...
by Dave
Sat Feb 25, 2023 5:04 pm
Forum: Hardware
Topic: My QXT640 thread
Replies: 22
Views: 3690

Re: My QXT640 thread

Was the XTAL on this QL changed from 15 MHz? No, it's a 15 MHz, just has hot glue around it for some reason. The first few machines people got, they would look in them and ooh and ahh a lot, and touch things, and the commonest problem was people breaking the xtal. Hot glue was an elegant solution t...
by Dave
Sat Feb 25, 2023 4:47 pm
Forum: For Sale
Topic: Tetroid TDI 1, Power Regulators and ROM Switchers ALL SOLD
Replies: 12
Views: 10421

Re: Tetroid TDI 1 + 2, Gold Card, Power Regulators and ROM Switchers

I'd like the TDI2 card, please.
by Dave
Fri Feb 24, 2023 6:31 pm
Forum: Hardware
Topic: My QXT640 thread
Replies: 22
Views: 3690

Re: My QXT640 thread

They were generic cases sourced by SPEM. The cases came with the front and back panels, which were all milled by hand. They were then powder coated and had the logos applied. Some of them, a step was skipped and they shed the white like crazy. A shame, really. The keyboard interface is absolutely wo...
by Dave
Thu Feb 23, 2023 8:05 pm
Forum: Hardware
Topic: Sandy RAM card, PAL blew up.
Replies: 10
Views: 971

Re: Sandy RAM card, PAL blew up.

The PAL is a lost cause. They are plain combinatorial logic, but the logic has surely been damaged by the component falling to pieces. Also, the DRAM can no longer be trusted. As I recall, the PAL just used the CLKCPU signal and /AS and /DS to work out the CAS and RAS parts of the address bus to pas...
by Dave
Thu Feb 23, 2023 6:26 pm
Forum: Hardware
Topic: Sandy RAM card, PAL blew up.
Replies: 10
Views: 971

Re: Sandy RAM card, PAL blew up.

Hehe, well spotted. Any other expansion can fit on that connector, so you could use another 512K RAM expansion of a different brand if you like. Somewhere around here I have a vintage 512Kx8 SRAM version of the thru-con RAM card. It's not too different in logic from the internal 512K expansion. I'm ...
by Dave
Thu Feb 23, 2023 5:40 pm
Forum: Hardware
Topic: Sandy RAM card, PAL blew up.
Replies: 10
Views: 971

Re: Sandy RAM card, PAL blew up.

Unfortunately, this is a bit out of warranty. :D The card is simply a thru-con RAM card with the DIN connectors not fitted. I didn't assemble/test that specific SQB board as mine only had pins fitted where signals were used. Sorry, I don't have the PAL equations. I wish I did - they would solve a lo...