Search found 13 matches

by derek
Fri May 31, 2019 9:13 pm
Forum: SALES
Topic: For Sale: ZX81 Learning Lab
Replies: 0
Views: 2372

For Sale: ZX81 Learning Lab

ZX81 Learning manual and tapes for sale.

Untested on ZX81, but I would the tapes to load OK.

Price: £10.00

Postage extra, based on location
by derek
Sat Aug 11, 2018 10:01 am
Forum: Spectrum BASIC
Topic: Spectrum Basic Variables
Replies: 3
Views: 9626

Spectrum Basic Variables

Hi, I have been reading some Spectrum Basic programming books, I was wondering if a variable can have the same name as an array, i.e. LET score=0 and DIM score(50) Both seem to be allowed by the Spectrum Basic interpreter, but clearly bad programming practise to have an array the same name as a vari...
by derek
Mon Feb 08, 2016 7:42 pm
Forum: Hardware
Topic: Spectrum+3 Composite Video
Replies: 1
Views: 1918

Spectrum+3 Composite Video

Hi,

Would the Composite Video mod for the 48K Spectrum, work on a Spectrum+3. I am hoping the modulators in the +3 is similar to 48K machine.

I will have a go and report back

Regards,
Derek
by derek
Tue Jan 19, 2016 8:52 pm
Forum: Hardware
Topic: Spectrum +3 Disk Drive
Replies: 1
Views: 1723

Spectrum +3 Disk Drive

Hi,

Seen a Plus 3 on ebay, with a 3.5" disk drive fitted.

I always thought this would a good idea. But this make the computer incompatible with 3" disks.

Another thought would fit an ST Card reader in place of the disk drive, which is the best.

Regards,
Derek
by derek
Mon Aug 24, 2015 9:43 pm
Forum: Hardware
Topic: Interface 1 Rom Upgrade
Replies: 8
Views: 5612

Re: Interface 1 Rom Upgrade

Hi Mark,

I put the IF1 rom in my All03a programmer and set the software to TMS2564 and rom was read into memory.

I have got 2 x TMS2564 eproms coming from Germany only £6 each.

Pity a static ram chip could not installed so custom rom images could loaded.
by derek
Sun Aug 23, 2015 11:16 am
Forum: Hardware
Topic: Interface 1 Rom Upgrade
Replies: 8
Views: 5612

Re: Interface 1 Rom Upgrade

Hi Mark, Thank you for the information with regards to the M2764 eprom. According to the Texas Instruments TMS2564 datasheet (attached) is pin compatiable with the TMS 4764 ROM, with the exception of: Pin 1: Vpp Pin 2: CS1 Pin 27: CS2 Pin 28: Vcc I was going burn Rom v2 into a TMS2564, with my HILO ...
by derek
Sat Aug 22, 2015 10:34 am
Forum: Hardware
Topic: Interface 1 Rom Upgrade
Replies: 8
Views: 5612

Re: Interface 1 Rom Upgrade

Hi Mark, Thank you for the web links and information, solves most of the issues. Looks like Interface 1 v3 Rom was not released. I just need to find a suitable Eprom to update the v1 Rom code. The Interface 1 service manual suggest the ROM is: Motorola SCH9288 OP or Teaxs TMS4764NLZA Whether these c...
by derek
Fri Aug 21, 2015 4:44 pm
Forum: Hardware
Topic: Interface 1 Rom Upgrade
Replies: 8
Views: 5612

Interface 1 Rom Upgrade

Hi,

I have an Interface 1 with a version 1 Shadow Rom, I would like to update it to Version 2.

Does anyone know where I could get a rom image of Interface 1 Version 2.

I read on Dataserve Retro site that there maybe a version 3 rom, was that ever released.
by derek
Wed Jun 10, 2015 11:00 pm
Forum: Hardware
Topic: Forth ROM
Replies: 1
Views: 1026

Forth ROM

Hi,

Can I replace the ZX81 ROM with a Forth ROM.

Regards,

Derek
by derek
Mon May 11, 2015 10:15 am
Forum: Hardware
Topic: ZX81 Laptop
Replies: 3
Views: 1991

Re: ZX81 Laptop

Hi,

This looks like the Spectrum laptop using a similar 7" LCD screen, there is also a 9" variation.

I did track down the author's website and download a hardware manual for Spectrum projects, which some could be applied to the ZX81, maybe...

Regards,

Derek