Search found 1312 matches

by Pr0f
Thu Feb 08, 2024 2:00 pm
Forum: The Off-Topic Section
Topic: Today I Received...
Replies: 643
Views: 297948

Re: Today I Received...

I wonder where that was - as the postcode is no longer registered - no 3BR - but there is a 3RB on the high street.

Were they in the offices by the station I wonder?
by Pr0f
Wed Feb 07, 2024 11:00 am
Forum: General QL Chat
Topic: In the market
Replies: 14
Views: 2559

Re: In the market

For most of the older QL's I've seen - the caps are usually in quite good order - the only ones you may want / need to look at are around the supply circuitry behind the Microdrives and under that heatsink. Membranes can still be had new for about £15 or so and not too difficult to replace, it's usu...
by Pr0f
Wed Feb 07, 2024 9:33 am
Forum: Hardware
Topic: Noisy MDV
Replies: 21
Views: 941

Re: Noisy MDV

I had a noisy microdrive and resolved it using some 'slug slime' - a fine modelers lubricant - just a drop on the top and bottom of the motor, and run it for a while - it should quieten down. Was the problem a noisy motor? and the lubricant lubricated the motor drive shaft? Yes - bearing probably -...
by Pr0f
Wed Feb 07, 2024 7:18 am
Forum: Hardware
Topic: Noisy MDV
Replies: 21
Views: 941

Re: Noisy MDV

I had a noisy microdrive and resolved it using some 'slug slime' - a fine modelers lubricant - just a drop on the top and bottom of the motor, and run it for a while - it should quieten down.
by Pr0f
Wed Jan 31, 2024 11:06 am
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 2187

Re: ICL OPD BASIC now in ROM!

I am wondering if any settings are cached in the 2K SRAM regarding the locations of things discovered in the config? The manuals that have been scanned are missing a few pages, but I know that some information is stored in the RAM besides telephone numbers - so perhaps a list of available ROM's may ...
by Pr0f
Tue Jan 30, 2024 10:15 pm
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 2187

Re: ICL OPD BASIC now in ROM!

I don't think just trying to read from that address would cause that problem - as the data is in ROM.
by Pr0f
Mon Jan 29, 2024 7:57 pm
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 2187

Re: ICL OPD BASIC now in ROM!

Looking at your mods around IC2 the 74LS138 - this would replace the A15 with the A16 address line, leaving A15 to be used for pin1 on the ROMs. This put's your BASIC ROM at 0x80000 by my calculations I was planning on trying this at 0xB0000 - as that address is free in the decoding map - be interes...
by Pr0f
Mon Jan 29, 2024 7:07 pm
Forum: Compatibles Corner
Topic: ICL OPD BASIC now in ROM!
Replies: 12
Views: 2187

Re: ICL OPD BASIC now in ROM!

I'm planning on making a similar mod - but replacing both logic chips on the right hand (processor) side of the PCB, and doing the same trick - three x 64K blocks - and the remaining socket switchable for either 128K ROM or RAM at the address designated for RAM expansion - for RAM to work - the code...
by Pr0f
Fri Jan 26, 2024 7:09 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 171599

Re: ICL OPD

The other PCML disk interface had a 64180 CPU and ran CPM - so it may be a CPM format or derivative?
by Pr0f
Thu Jan 25, 2024 10:24 pm
Forum: Compatibles Corner
Topic: OPD: Computer One floppy interface recreation.
Replies: 26
Views: 20466

Re: OPD: Computer One floppy interface recreation.

I pulled the lid off a ROM module, and pin 27 is just tied to ground. The resistor - value 2.7K goes from +5v to pin 1 of the Eprom, and the capacitor is tied between 0v and +5v. I think the same tying to ground would work perfectly well for the disk interface. I think the ICL OPD only decodes the /...