Make this my favourite vLA81 : A Sinclair ZX81 ULA replacement + External Configuration Switch

Retro Computers >> Sinclair >> Sinclair ZX81 >> Components
Listing type:
Fixed Price Multiple Items
Item Condition:
Seller location:
Katikati, New Zealand
Ending in:
This listing is closed (18/02/2020)

Notify When Back in Stock
Quantity Available
Latest buyer:
c***s (2)
Fixed price:
Shipping Costs:
From only £2.00
Payment methods:
Number Sold:
2 (View history)
Buyer Value Date and hour Quantity bought
c***s (2) £22.95 13/02/2020 18:25:05 1
k***l (1) £22.95 07/02/2020 00:09:03 1

Item Number : 40602

Meet the seller

Bloodnok (153) User Offline

Contact the Seller
Add Seller To Favourites
See Other Items

View webstore vRetro Design


This offer is for a vLA81 + External Configuration Switch

The vLA81 is a modern plugin replacement for the ZX81 ULA. It is one of several ULA replacements I have made for members of the Sinclair computer family including the vLA82 for the Spectrum 48K, the vLA128 for the Spectrum 128K (Toastrack) and +2 (Grey case) and the vLA1 for the Sinclair ZX Interface 1.

As they simply don't make ZX81 ULAs anymore, then unfortunately if the ULA has failed (and there's not much else on a ZX81 to fail), then options for repair are rapidly diminishing. The vLA81 provides a simple way to keep these icons of 80's computing going.

Apart from providing the functionality of both the earlier 2C158E/184 ULA (without back porch) and the 2C210E (with back porch), the vLA81 also has a few extras added.

vLA81 features:

  • Fits within the same 40 pin DIL socket outline as the original ULA.
  • Narrow IC pins for easy plugin ULA replacement. In most cases the existing socket will be OK (unless, of course, the existing ULA is soldered in).
  • Provides the same functionality as the 2C210E Sinclair ULA by default.
  • Video level selectable between standard video (suitable for direct connection to a 75 ohm monitor input) and high sync level (suitable for the modulator input or some video mod boards).
  • Back porch on/off select.
  • Internal 32K memory support (High or Low for the different hires schemes). Note that the M1NOT mod is not needed with the 32K internal memory. Existing M1NOT enabled internal memory will work fine with the default ZX81 memory mapping selected.
  • Programmable user configuration gives access to:
    • Inverse or normal video and choice of black or white border.
    • 50/60 Hz video standard.
    • Ability to map ram to the ROM space (write protect enable/disable – 32K internal ram required).
    • Includes configuration port socket on PCB base and external config switch.
  • Tested with an extensive suite of ZX81 software.
  • Ideal for preserving the original ZX81 ULA.
  • Low power consumption.


Note: If you require the external configuration switch assembly then please let me know.

Whether you want to just get a faulty ZX81 back up and running, or want to extend the ZX81 with expanded memory and HIRES, the vLA81 can provide what you need.


Picture gallery

  • vLA81 : A Sinclair ZX81 ULA replacement + External Configuration Switch
  • vLA81 : A Sinclair ZX81 ULA replacement + External Configuration Switch
  • vLA81 : A Sinclair ZX81 ULA replacement + External Configuration Switch
  • vLA81 : A Sinclair ZX81 ULA replacement + External Configuration Switch

Questions and Answers

Shipping and Payment

Item Location:
Katikati, New Zealand
Shipping conditions:
Buyer pays shipping expenses
Shipment fee:
  • To New Zealand :
  • First Class Post : £2.00
  • Courier : £4.00
  • To EU :
  • Airmail Post : £7.50
  • To Europe (Non EU) :
  • Airmail Post : £7.50
  • To Americas :
  • Airmail Post : £7.50
  • To Rest of World :
  • Airmail Post : £7.50
Shipment terms:
Not specified
Payment methods:

The seller accepts all responsibility for this listing

Page view: 168