Search found 48 matches

by Muttley Black
Thu Jan 21, 2021 10:38 am
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

bola_dor wrote: Thu Dec 17, 2020 4:39 pm Some times I have to make it SAVE in the blid at start to guet it to sync...
If your tv refused to sync, try that if you want:


Image
by Muttley Black
Tue Jan 19, 2021 11:54 am
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

Thank you so much Mark. I will study all the above. By the way I was ready to post some changes. I decided to make the composite video to work on my mini crt and only. The following changes I made don’t work with lcd tv: I did make again the following circuit but, i didn’t change R30 with 470ohm res...
by Muttley Black
Tue Jan 19, 2021 5:05 am
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

Some news. I made that circuit again: https://i.postimg.cc/PPpsz20H/457-C5014-E5-CF-49-D4-9-C64-E580697586-B4.jpg But with the difference that i didn’t use the 100ohm resistor at all. Also i replace R32 resistor on the motherboard with diode 1N4148 with cathode looking at sync ic19 way. The results:...
by Muttley Black
Sun Jan 17, 2021 10:25 am
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

Yesterday I tried to put a modulator from a zx spectrum. This make my zx80 post a great picture. https://i.postimg.cc/v1vSNWvQ/1-B6-E4736-79-B1-4-A8-A-A0-CF-287341012-C3-F.jpg https://i.postimg.cc/JD6Y1Mgv/BA80753-B-B487-434-D-8-BD8-F60-AEEEB7-B2-C.jpg The problem was that the rca was at the other w...
by Muttley Black
Mon Dec 21, 2020 8:33 pm
Forum: Hardware
Topic: Arduino 4116 tester FINAL! Free Gerbers.
Replies: 4
Views: 2443

Re: Arduino 4116 tester FINAL! Free Gerbers.

Link on first post is dead.

Here is the new one: http://www.mediafire.com/file/884tyy88p ... r.rar/file
by Muttley Black
Sun Dec 20, 2020 6:24 pm
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

After hit "RUN" tv loss signal and get back with "0/20" and big vertical black line, as before.
by Muttley Black
Sun Dec 20, 2020 5:08 pm
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

(replace R1 with a fixed 2.2kΩ resistor in series with a 4.7kΩ preset). Mark I did that. Not exactly with the same values, but close. This let you play with back porch length, if I understand well. Here is some outputs by play with the resistance: https://i.postimg.cc/9rs9myjP/FC1-FB924-4-B97-4-AE8...
by Muttley Black
Sun Dec 20, 2020 3:15 pm
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

bola_dor wrote: Sun Dec 20, 2020 3:02 pmme point. Then I could never make it work on the ZX80. (Mine is a 60Hz USA version BTW)
Me too, but in my case D11 is missing.


Next step:

Image


And we will see! :)
by Muttley Black
Sun Dec 20, 2020 2:01 pm
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

I really don't know. I am confused... looking at the following video, after 9:40, the guy use the same zigg circuit on a zx81. If you see the first test was on a mini tv. he got very nice picture but with missing texts, like me. At the and he test it on a big tv and all was great. https://www.youtub...
by Muttley Black
Sun Dec 20, 2020 1:35 pm
Forum: Hardware
Topic: My first ZX80.
Replies: 78
Views: 20754

Re: My first ZX80.

The modulator is out from the motherboard, but this doesn’t matter. So, here is the output of R32: https://i.postimg.cc/kV9cGY4x/60142938-EBD4-43-A4-8705-0800-A4990335.jpg Here is what I get from IC19 pin 5: https://i.postimg.cc/mP4Myzs4/F335-E19-B-2-B63-421-F-A60-C-02-D082-E1919-C.jpg And here is I...