My first ZX80.

Discussions about Sinclair ZX80 and ZX81 Hardware
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Muttley Black
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Joined: Thu Apr 18, 2019 7:54 am

My first ZX80.

Post by Muttley Black »

Hello all! :)

I just buy my first ZX80 and I am more than happy.
Motherboard is issue 3. I get this as untested and I am looking forward to make this beauty healthy again.

There are a special schematic for issue 3?

My zx80 have marked as USA but this is UK keyboard am i right?

Thank you.
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Moggy
Posts: 2089
Joined: Wed Jun 18, 2008 2:00 pm

Re: My first ZX80.

Post by Moggy »

I notice the diode marked D11 has been removed so I assume this will work as is on UK TV, or does the modulator make a difference?(question aimed mainly at Mark when he sees this)

This thread may be useful to you...

https://www.sinclairzxworld.com/viewtop ... f=7&t=3266
Last edited by Moggy on Fri May 22, 2020 3:03 pm, edited 1 time in total.
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: My first ZX80.

Post by 1024MAK »

Moggy got there first :lol:

[Besides, viewing detail in photos on a small screen is not easy...]

Mark
Moggy
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Joined: Wed Jun 18, 2008 2:00 pm

Re: My first ZX80.

Post by Moggy »

Sorry Mark I've added a question about the modulator does it make a difference or is it just the diode?
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Muttley Black
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Re: My first ZX80.

Post by Muttley Black »

Thank you both.

Mark I add better photos when I got it in my hands.
The beauty still traveling!

What about the schematic for issue 3?

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

Re: My first ZX80.

Post by 1024MAK »

We only have one schematic for all ZX80s as far as I know. This is the schematic (or a redrawn version) of that which Sinclair provided with the kit ZX80s. My ZX80 has an issue 2 board.

The different modulators (normally VHF for the USA and UHF for Europe) only affect the allocated frequency for a (nominal) ‘TV channel’ (in Europe its channel 36). This does not affect the 625 line / 50Hz or 525 line / 60Hz video format. But obviously for the VHF modulator, if a using RF/aerial connection, your TV must be able to receive VHF channels.

On the keyboard, as far as I know, there was only ever one layout.

Mark
Lardo Boffin
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Joined: Sat Nov 26, 2016 2:42 am

Re: My first ZX80.

Post by Lardo Boffin »

This is a link to a scan from assembly instructions:

https://www.sinclairzxworld.com/viewtop ... 894#p36894
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Spectrum +2a
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Muttley Black
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Joined: Thu Apr 18, 2019 7:54 am

Re: My first ZX80.

Post by Muttley Black »

Great. Thank you for the info
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Muttley Black
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Joined: Thu Apr 18, 2019 7:54 am

Re: My first ZX80.

Post by Muttley Black »

Yesterday i got it in my hand's. I buy it as Untested.

here are some photos :)

Image

Image

Image

Image

Image

And some from inside

Image

Image

Image

Image

And this is what i get in my screen.

Image


This beauty need a repair ;)
Moggy
Posts: 2089
Joined: Wed Jun 18, 2008 2:00 pm

Re: My first ZX80.

Post by Moggy »

Congratulations Muttley Black on your splendid looking 80. :D

I'm sure Mark will be along with some sage advice on how to proceed( he saved my 80 from the scrap pile).

A few observations.

The ceramic caps and resistor around the EAR?/MIC sockets seem to have been added as a rudimentary hi pass filter to improve LOAD/SAVE which I have always found unnecessary as the 80's output is much louder than say the 81, and I never had a problem with tape LOAD/SAVE although now I use the ZXpand with my 80.
The cap on the power socket I would suggest is just for removing any spikes on the supply line.

I notice also you have plugged it into a modern LG LCD TV. I would be surprised if you got a picture of any sort as without modification the humble 80 really is really more used to being used with a CRT TV.
With a Modern LCD set I could never get a picture through the modulator so in the end modified it for composite output.

I look forward to seeing this little gem being fully restored please keep us informed of progress.

Regards.

Moggy.
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