Search found 69 matches

by S_U_C
Sun Jun 06, 2021 7:44 pm
Forum: Other
Topic: Machine Code program
Replies: 2
Views: 2257

Re: Machine Code program

I believe this to be someone’s attempt at converting KNIGHT'S M/C VSN 3.1 and it contains bugs the obvious one is the paper out error which prints paper out but then is coded to print out part of the “no printer” error message half way though a word. Also the first 9 bytes have been corrupted with F...
by S_U_C
Wed Feb 17, 2021 11:26 pm
Forum: Hardware
Topic: MZ-80B project (Floppy Disk I/O Card cloning!)
Replies: 23
Views: 20578

Re: MZ-80B project (Floppy Disk I/O Card cloning!)

Hi I found a large A3 scan of the MZ-80A floppy disk card, this will work in the B if you dissable the CS/CE to the EPROM IC 3 PIN 8 to IC 5 PIN 1. add pull-up resister to IC 5 PIN 1
by S_U_C
Wed Feb 17, 2021 11:17 pm
Forum: Buy/sell
Topic: WTB: MZ80B FDD controller card
Replies: 5
Views: 5679

Re: WTB: MZ80B FDD controller card

I was correct there is one track that has to be cut to convert the A card to a B card the EPROM's CS/CE signal IC 3 PIN 8 to IC 5 PIN 1
IC 5 PIN 1 will need a pull-up resistor adding. see images
by S_U_C
Wed Feb 17, 2021 11:07 pm
Forum: Other
Topic: Original software from SUC for MZ 800
Replies: 4
Views: 3925

Re: Original software from SUC for MZ 800

Hi the Sharp Users Club had died 1980-2020 due to lack of members, Last SUC magazine 2020 vol2 November issue is still at the printers (lockdown problems) I have a large selection of tape and disks for various Sharp machines. I have an 800 basic disk marked PIXEL (EPSON) but can not access it, as al...
by S_U_C
Wed Feb 10, 2021 5:53 pm
Forum: Buy/sell
Topic: WTB: MZ80B FDD controller card
Replies: 5
Views: 5679

Re: WTB: MZ80B FDD controller card

Do you want to run CP\M or do you want to extract data from the disks? I have a KroFlux and can read the disks except the boot sector, but I know what it is anyway. And I have my own software that can mount the KroFlux file and display directories and extract files. The Mz-80A FD card will work in t...
by S_U_C
Thu Sep 10, 2020 9:20 am
Forum: Hardware
Topic: Mz80-A no cursor
Replies: 8
Views: 6934

Re: Mz80-A no cursor

I had a similar fault on a MZ80K. I was the flash timer is not working. The K used a 555 timer and the MZ80A uses a 556 (IC51)+ caps C39,C40 On the A the start up order is the setup clear screen print ** MONITOR SA-1510 ** test for he USER ROM/RAM at $E800 (IC43 next to the Monitor ROM) print Newlin...
by S_U_C
Wed Jul 15, 2020 2:45 pm
Forum: Demoscene
Topic: MZ-700 demos
Replies: 88
Views: 97631

Re: MZ-700 demos

Note: just to make things more interesting The MZ-80K and MZ80A ROM and RAM opcode timings are the same. But the MZ700 runs opcodes faster in RAM than ROM as the LSI chip controls the /WAIT ine of the CPU and it adds 1 extra T-cycle to the opcodes in ROM. This speeds up the tape read/write routines ...
by S_U_C
Mon Jun 15, 2020 10:06 am
Forum: Hardware
Topic: MZ 80K repair project
Replies: 24
Views: 21789

Re: MZ 80K repair project

Sounds like the horizontal synch has failed.
Check test points 13 to 21 on the video board with an oscilloscope, ( see page 40 of the MZ80K Service Manual) and compare with traces on pages 19/20.
by S_U_C
Wed Jun 10, 2020 2:20 pm
Forum: Hardware
Topic: MZ 80K repair project
Replies: 24
Views: 21789

Re: MZ 80K repair project

Check that capacitors C407 c406 c503 or c504 are OK. I can remember repairing a K power supply (that kept blowing fuses ) for MH in Weymouth many years ago by replacing the blue capacitors which are part of the voltage setting circuit. I think one was short circuited but we replaced all 4. ESR is sh...
by S_U_C
Mon Apr 06, 2020 11:26 am
Forum: Hardware
Topic: MZ700 video problem
Replies: 25
Views: 19732

Re: MZ700 video problem

Hi I have a MZ80K with the same problem. A static random screen, the pattern is always the same on power or reset. I reproduced the fault on another MZ80K by testing a RAM checker eprom that it did not work in the faulty machine. The both MZ80K could not see the eprom,the eprom was too slow 350ns. a...