Hi
I've just bought my first ZX80, and at some point in the past it has had a rough and ready composite mod done to it (the same type as you can do the the spectrum). my question is can you improve this with a capacitor, like on the spectrum, or is it better to do the transistor composite mod
Thanks
Andy
ZX80 Composite Mod
- 1024MAK
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Re: ZX80 Composite Mod
Hello Andy
Because the video is mixed with the sync signal via resistors (for both the video and the sync), an active amplification stage is recommended, hence I suggest the transistor version. You can see my transistors version for the ZX81 via the link in my signature (below).
Mark
Because the video is mixed with the sync signal via resistors (for both the video and the sync), an active amplification stage is recommended, hence I suggest the transistor version. You can see my transistors version for the ZX81 via the link in my signature (below).
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: ZX80 Composite Mod
For a ZX80, that never had a backporch, I recommend adding a backporch generating device. I use Pokemon's version.
Kind regards Paul
Kind regards Paul
In theory, there is no difference between theory and practice. But, in practice, there is.
- 1024MAK
- Posts: 5118
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: ZX80 Composite Mod
Yes, his ZX8-CCB is what I would normally recommend, but his shop is currently closed due the the COVID19 Corona virus outbreak. His Sell My Retro shop is here.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: ZX80 Composite Mod
Thanks for the advice guys, I'll have a look at both your circuit Mark and Pokemon's as well
Thanks
Andy
Thanks
Andy
Re: ZX80 Composite Mod
I have my ZX80 connected with non backporch mod but the TV takes it well. I was lucky I guess. Some times I have to force it making it SAVE and when back the video is OK.
But if you are not lucky with the TV with the simple transistor mod you can go with the 555 based mod that builds the missing backporch
http://zx.zigg.net/misc-projects/
But if you are not lucky with the TV with the simple transistor mod you can go with the 555 based mod that builds the missing backporch
http://zx.zigg.net/misc-projects/
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come