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Sinclair ZX81 computer – Refurbished and Upgraded to 32K RAM and HRG Ready with new VLA81

1 customer review

£139.99

Thanks for looking at our Sinclair ZX81 computer – Refurbished and Upgraded to 32K RAM and HRG (Hi Res Graphics) Ready!  Issue 1 Board with a new VLA81.

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Description

Thanks for looking at our Sinclair ZX81 computer – Refurbished and Upgraded to 32K RAM and HRG (Hi Res Graphics) Ready!

ZX81 ACED-RDR-017-IMG_3265Issue 1 Board with a new VLA81 (the ZX81 ULA replacement)

We’ve performed the following work on this little beast:

  • Replaced the old ULA with a new VLA81 fitted with a heatsink
  • Replaced the paltry 1K memory with a 32K SRAM chip using a custom PCB – now the ZX-81 has 32K RAM internally! No more RAM pack wobble – and you get to use hires graphics (HRG) as the custom PCB also enables that. You can also disable the HRG8 function with the new revision of our PCB by removing the jumper.
  • All electrolytic capacitors have been tested to make sure that the ZX-81 has a stable power supply.
  • The insides of the RF modulator have been swapped out for another custom PCB that gives the ZX-81 excellent composite video output and produces the needed back porch to allow the ZX81 to give a crystal clear picture on modern TV’s – and it uses the same socket as the RF modulator used to so that we don’t have to modify the case at all.
  • New keyboard membrane and all keys on keyboard tested to ensure fully working.
  • Comes with its original Sinclair ZX-81 power supply. The power supply has also had its electrolytic capacitors tested.

All in all, this is a well upgraded, refurbished Sinclair ZX-81 computer with a case which is very tidy. ZX81 ACED-RDR-017-IMG_3266ZX81 ACED-RDR-017-IMG_3267

The little man even has new rubber feet to replace the old stinky shoes he used to have!

If you have any questions about this Sinclair ZX81 computer or any of the other computers or modifications on our site then please do not hesitate to contact us.

To learn more about the VLA81 check out vdrivezx.com!

Additional information

Weight 2 kg
Dimensions 45 × 35 × 16 cm

1 review for Sinclair ZX81 computer – Refurbished and Upgraded to 32K RAM and HRG Ready with new VLA81

  1. AK (verified owner)

    Fantastic service from RDR, the ZX81 was packed very well. Switched the ZX81 on and it fired up right away … memories of the 80s start flooding in. I had a Wagon Wheel moment as I thought some how the ZX81 was bigger. Super machine, great for the collection. Thank you Mark for all your help.

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