MZ-80b FI/O to HxC Cable

psmart
Posts: 131
Joined: Thu Nov 21, 2019 10:12 am
Location: Leeds
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by psmart »

Good to know, keep us updated should anything else arise. Always a concern with a new board/components, it worked well for the +hour I tested it in both the MZ-800/MZ-2000 but that is no guarantee especially as the buffer chips around the Z80 degrade over time and the timing goes a little awry (which I found out on my RFS board when it worked perfectly in my machine but in another guys it didn't, software drivers had to be adjusted to compensate).

I normally like to get machines pristine and strip them down and clean all the circuits/replace caps, clean up the plastic etc, but the MZ-80B isn't plastic, rather painted/coated metal, so not sure what the procedure would be to get a machine back to the condition like yours is in, perfect condition.

I have to recap an MZ-2000 monitor this week, the vertical driver circuit has failed so got a new vertical driver IC and all the caps and if successful will do the same to my MZ-80A as it has a bit of a vertical size restriction, capacitors again! You may need to do the same.
Sharp MZ/X Series Projects and FPGA Emulator
engineers@work : https://eaw.app/sharpmz-series/
arnuphis
Posts: 43
Joined: Fri Jul 31, 2020 4:18 pm

Re: MZ-80b FI/O to HxC Cable

Post by arnuphis »

I recapped my power supply a while back. I will probably look at the Monitor board next once the component supplies pick up. I have been waiting 6 months for parts for my spare mac SE/30 power/flyback board. Thank you covid.

I have a spare MZ-80 while is one I use for supplies as its in a rough cosmetic condition. I will check the tube on that one as well just in case its the tube itself that is getting old in my main machine as opposed to it being a cap/convergence issue.

Now I need to get my hand on some of the games. I saw there was a pac man clone and a space invaders clone but I have yet to see them in any .dsk format. Maybe they were tape only?

Now the system seems stable I can actually start working on some programs for it.
psmart
Posts: 131
Joined: Thu Nov 21, 2019 10:12 am
Location: Leeds
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by psmart »

One of the things which is needed is a disk to tape copy utility, that way it is easy to regenerate the cassettes. I tried to get the PC program on original.sharpmz.org running on a T30 to generate 80B/2000 cassettes but wasted a day with no success, guess you need an AT or 386 for it!
Sharp MZ/X Series Projects and FPGA Emulator
engineers@work : https://eaw.app/sharpmz-series/
arnuphis
Posts: 43
Joined: Fri Jul 31, 2020 4:18 pm

Re: MZ-80b FI/O to HxC Cable

Post by arnuphis »

Figures. I cleared out my PC Stuff so all I have is modern machines. I guess a trip to the thrift store may be in order. Ebay prices are nuts for 386s.
psmart
Posts: 131
Joined: Thu Nov 21, 2019 10:12 am
Location: Leeds
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by psmart »

If you can lock the PC to a fixed speed then the assembler source code (provided) can be modified - it is supposed to use the 8254 timer but on the scope the marks/spaces were quite a bit out, ie 390uS instead of 366uS and the scope was dancing, even on the lead in, it couldn't get a fixed sync (had to manual trigger) so Im guessing the speed step was interfering. I tried to adjust the tracking speed of the tape drive to compensate for the timing difference and got it to read the header but the main program always had a CRC error. I also found the tape quality was important, old 'computer cassettes' didn't cut it, had to be a new TDK or the original sharp tapes (used the blank B side of the MZ-2000 application tape).

I plan to modify my RFS board software on the MZ-80A to write at 1800 baud, the source for the read is in the MZ-80B IPL but not the source for write albeit looks very similar, apart from timing delays and header pulse count, to the MZ-700 code. Another task!!!
Sharp MZ/X Series Projects and FPGA Emulator
engineers@work : https://eaw.app/sharpmz-series/
User avatar
dat-alex
Posts: 34
Joined: Tue Dec 04, 2018 7:18 am
Location: Greece
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by dat-alex »

arnuphis wrote: Sun Jul 04, 2021 7:03 pm I actually ended up cleaning all the contacts on the edge connectors in the I/O bay and the pins on the MB and everything seems to be working now. I also switched over to the Gotek which works fine too.
@arnuphis. Hi,myfriend: I have connected Gotek with psmart SFD800 pcb on my 80B but I cannot make it work ,(in order to make some tests before proccess with my FPGA redesign stage ;) )

Could you please inform me of your Gotek FW and cfg settings? . I have also convert .dsk to .hfe on my usb . (Seeking led turns on with no loading)
all.jpg
member of retroclub.gr (Thessaloniki , Greece)
psmart
Posts: 131
Joined: Thu Nov 21, 2019 10:12 am
Location: Leeds
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by psmart »

Hi,

If the card was working you should see the FD Loading error and a menu with C: CMT, F: Floppy Disk being presented. The screen you show seems to me to indicate only the CMT could be found. When you turn on the floppy disk should automatically activate and (on my HxC) stepping activity can be seen. If there is a configuration or data error, after a few retries you will get the Floppy error message + menu. If you dont have the disk (Gotek) connected and power on you should immediately get the Floppy/CMT menu.

Check the SFD800 card and the expansion box. Also, the 34pin connector on the SFD800 is in reverse so you have to reverse the cable (ignore the index plastic, force it in), I never understood why this was but duplicated the card as per the original.

Hope this helps.
Sharp MZ/X Series Projects and FPGA Emulator
engineers@work : https://eaw.app/sharpmz-series/
User avatar
dat-alex
Posts: 34
Joined: Tue Dec 04, 2018 7:18 am
Location: Greece
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by dat-alex »

@psmart : Thank you for your infos.
psmart wrote: Sat Sep 25, 2021 5:47 pm .....Check the SFD800 card and the expansion box. Also, the 34pin connector on the SFD800 is in reverse so you have to reverse the cable (ignore the index plastic, force it in), I never understood why this was but duplicated the card as per the original.
...
I've already find out this and have cable reversed

I checked if clock is alive (pin 18 on 1773) with my RIGOL and guess>>>>....no pulse. I changed to another 16Mhz crystal with no live pulse again.
This time I used other crystal 12Mhz & 10 Mhz and I got 6Mhz and 5Mhz output pulse (as expected!).

Weird! maybe both my 16Mhz crystal is faulty or fake (!)

I left 10Mhz on pcb to make some test. Per your instruction I get the C: CMT, F: Floppy Disk being presented message stepping activity present on Gotek led and I get an error-message+menu. With Gotek disconnected I immediately get the Floppy/CMT menu as you stated.

I think I am in the write path. Maybe there is image problem on SD or bad cfg file. (May arnuphise would be helpful here ;) )

Thank you for all your help....
Image3.jpg
Image3.jpg (61.23 KiB) Viewed 153 times
member of retroclub.gr (Thessaloniki , Greece)
psmart
Posts: 131
Joined: Thu Nov 21, 2019 10:12 am
Location: Leeds
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by psmart »

Hi, the crystal impedance matching and capacitance is very important, i’ve come unstuck on my MZ80A video board with this issue, check the capacitors (on original one of them was removed as I guess the crystals specs of the manufacturing units were different to the design. On my first run of this board i had the same issue and had to reduce the bias resistors to 560R to get reliable oscillation.
Sharp MZ/X Series Projects and FPGA Emulator
engineers@work : https://eaw.app/sharpmz-series/
User avatar
dat-alex
Posts: 34
Joined: Tue Dec 04, 2018 7:18 am
Location: Greece
Contact:

Re: MZ-80b FI/O to HxC Cable

Post by dat-alex »

Well I changed one cap from 3.3n to 15p (I had in box) and now I get a clean 8Mhz clock output

osc3.jpg
osc3.jpg (59.9 KiB) Viewed 125 times

Now it seems that something is going on!

I can get IPL loading message but stuck there... at boot

osc1.jpg
osc1.jpg (50.44 KiB) Viewed 125 times

At least I know my WD1773 (and psmart pcb ;) ) is working maybe there is something wrong with Gotek .cfg or disk images
member of retroclub.gr (Thessaloniki , Greece)
Post Reply