The Sinclair QL Forum

Just had a quick look on eBay for Z88s and accessories, feeling a little nostalgic after getting rid of my Z88 some years ago. Like many retro systems, the prices they go for somewhat amazed me! I occasionally look at Z88 on Ebay and it does appear fickle, some long standing listings are pricey but...

Ideally you want one with an LED. I added one to mine since it was too easy to be unaware you were running on batteries and the mains switch wasn't on

If this byte sequence is used only for 16KB bin files for the Rom slot what about the 32KB rom files? The byte sequence $4AFB0001 can be used for any size ROM files (within available space), not just 16K. AFAIK that sequence was chosen because it was least likely to occur in normal binary files. An...

AFAIK the 68K/OS(32KB) file is a complete operating system replacement so I don't expect it to be recognised by QDOS/Minerva. Though it will be interesting to see if t0nyt's 68K/OS PCB can be realised as a schematic

OK, the first thing to do would be to look at each of the files you wanted to add to EPROM in a hex editor. If they are true QL ROMable files then the format of the first few bytes is defined: $4A,$FB,$00,$01 unique identification word for ROM code $??,$?? offset to list of names of new SupreBASIC p...

Do the files in EPROM have the required ROM header ident/banners at the 16K boundaries where needed? It would be easy enough to knock up simple SuperBasic script to PEEK at the appropriate places and show first few bytes (i.e. at each 16K boundary in top 256K of QL's 1Meg map).

But also

Would doing a cartridge dump using FORMAT RAM1_MDV1 be possible? (assumes at least map is same as normal QL mdv.)

Surely nothing more than DIP resistor packs (pull ups?).

(Looks like variation on https://www.jupiter-ace.co.uk/hardware_ ... oller.html)

I would at least try a logic probe on eprom select (pin 22 /OE) to see if after a reset it is at least polled to help start narrowing problem down.

Edit: removed text about jumbled roms; V4 is jumbled

Edit2: I use 'jumbled' (not scrambled) since that is what QEP III uses.