ZX80 ZX81 Video options.

Discussions about Sinclair ZX80 and ZX81 Hardware
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KnightLore
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Joined: Thu May 17, 2018 3:33 pm

ZX80 ZX81 Video options.

Post by KnightLore » Thu May 17, 2018 4:45 pm

Hi all,

I have a ZX80 and a ZX81(my first computer in the 80's) I need help to connect them both to a CRT. The problem is the CRT screen is a production monitor. Its inputs are RGB/BNC, composite and svideo.

I would really like to not have to get them composite modded so i can keep them in their original state. I know they both work because i can get them working on an lcd. I however dont like the look. I use the monitor for my Commodores, my Harlequin board, my zx spectrum that does have composite mod and also for retro mame gaming with an arcade vga. It works really well for these and i would really like to try convert the signal without the modification. The ZX80 is already slightly cracked around the plastic rivets so i dont want to open it up.

Can it be done? If not, what are my other options?

Cheers.

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1024MAK
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Re: ZX80 ZX81 Video options.

Post by 1024MAK » Thu May 17, 2018 8:16 pm

There are only two routes.
  1. Add a composite video output
  2. Use a demodulator to get a composite video signal from the VHF/UHF TV output
If you use one of Pokemon's ZX8-CCB modules (currently out of stock) you can retain the existing VHF/UHF TV output. You can then have a composite video output on a lead with a phono/RCA line socket, so no need to modify the case.

Trying to find a separate demodulator these days may be tricky. See if you can find an old VCR. These often have demodulators. But you would have to work out how to use it. This may be a fairly complex project.

Mark

Moggy
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Re: ZX80 ZX81 Video options.

Post by Moggy » Thu May 17, 2018 10:52 pm

I have my ZX80 comp' modded with a ccb module and whilst it's ok on my colour CRT TV I get some bottom line distortion on my LCD TV which no amount of adjustment will get rid of.

KnightLore
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Re: ZX80 ZX81 Video options.

Post by KnightLore » Fri May 18, 2018 9:08 am

I remember using VHS video recorders as a signal passthrough quite a long time ago. It does work so maybe i might buy one off ebay and give it a go.

The ZX8-CCB module looks like a good option, but i would still need to open up the case and solder onto the mainboard. For the ZX80 this would be tricky and i would then need to find some more plastic rivets to put it back together.

I do own one of these, but i cannot get it to tune in. https://www.radiomuseum.org/r/sony_tv_511e_tv511.html

I would like to find an old retro TV that works.

Maybe i should just get them composite modded. Once its done i would then be able to use them on my production monitors which always give out such a good picture.

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mrtinb
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Re: ZX80 ZX81 Video options.

Post by mrtinb » Fri May 18, 2018 9:41 am

The Chroma Interface is your friend, if you will not open up your Sinclair. It's an external interface with a scart-connnection for your tv.

The ZX81 version:
http://www.fruitcake.plus.com/Sinclair/ ... erface.htm

The ZX80 version comes later this year:
http://www.fruitcake.plus.com/Sinclair/ ... erface.htm
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

KnightLore
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Re: ZX80 ZX81 Video options.

Post by KnightLore » Fri May 18, 2018 10:19 am

A few very good options here.

The Chroma would work if i found a scart to bnc cable. I use a vga to 5 bnc cable for my mame setup and combine the sync cables. So it is RGB and then 2 sync. I wonder how it would work in this scenario?

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