My first ZX80.

[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.

[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

[1024MAK]

Moggy got there first

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

Mark

[Moggy]

Sorry Mark I've added a question about the modulator does it make a difference or is it just the diode?

[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

[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]

This is a link to a scan from assembly instructions:

https://www.sinclairzxworld.com/viewtop ... 894#p36894

[Muttley Black]

Great. Thank you for the info

[Muttley Black]

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

here are some photos











And some from inside









And this is what i get in my screen.




This beauty need a repair

[Moggy]

Congratulations Muttley Black on your splendid looking 80.

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.