Replacing ZX81 power input

Discussions about Sinclair ZX80 and ZX81 Hardware
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Shaun_B
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Joined: Wed Apr 22, 2009 9:22 am

Replacing ZX81 power input

Post by Shaun_B » Thu Oct 26, 2017 11:11 am

Is it possible & relatively easy to change the power input on the ZX81 to use a Spectrum PSU?

Thanks,

Shaun

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Paul
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Re: Replacing ZX81 power input

Post by Paul » Thu Oct 26, 2017 11:23 am

The ZX81 pcb isn't ready to take a different input.
So an adapter cable is the best way to get a spectrum psu to work with the ZX81.
Be aware the spectrum plug is quite common and in 99% it's polarity is inverted. So there is possible danger of destroying your ZX81.
A simple diode that is capable of 2A load should prevent this. Or a full rectifier. Then you can use spectrum and other 7-14V power sources without any harm for your Zeddy.
Kind regards Paul
In theory, there is no difference between theory and practice. But, in practice, there is.

Shaun_B
Posts: 337
Joined: Wed Apr 22, 2009 9:22 am

Re: Replacing ZX81 power input

Post by Shaun_B » Fri Oct 27, 2017 6:02 am

Thanks Paul.

Is there a suitable replacement for a ZX81 power supply that I may purchase?

Regards,

Shaun

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Paul
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Location: Germanys west end

Re: Replacing ZX81 power input

Post by Paul » Fri Oct 27, 2017 7:13 am

There are plenty.
E. G. https://www.amazon.de/gp/aw/d/B002TQ220 ... th=1&psc=1
Put it on 7,5V and plug in the 3.5mm Jack (TIP Is plus)
Kind regards Paul
In theory, there is no difference between theory and practice. But, in practice, there is.

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Replacing ZX81 power input

Post by 1024MAK » Fri Oct 27, 2017 1:40 pm

I give advice on replacement power supply units here.

Mark

ts_mike
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Re: Replacing ZX81 power input

Post by ts_mike » Mon Oct 30, 2017 12:35 am

A power supply from an old Atari 2600 VCS game console has always worked well for my TS1000 (the US version of the ZX81). Careful if you buy a 3rd party supply. You'll want to have at least 700 mAmps and not all of the 3rd party ones supply that amount.

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