The ZX81

Well, the ZX first.   It's a 1980, issue 1 ZX81.  So it's only about a year younger than I am.  I also think it's the first time I've ever seen one of these machines in the flesh and it's ridiculously tiny.  The Membrane keypad is horrible.  And the resemblance to it's younger brother is more than just skin deep.  It's really obvious that this is the machine that Sinclair designed just before the Spectrum.



Anyway, A visit to Maplin and one overpriced PSU purchase later, and... nothing.

Turns out this is was my fault.  For some reason, Sinclair decided to change the PSU polarity between the ZX81 and the Spectrum, but I didn't realise this until later.  The 7805 Voltage Regulator got pretty hot, but fortunately it wasn't on too long and it doesn't seem to have done any long-term damage.  Not that a 7805 is a difficult component to replace.

So, a 9VDC Power supply was all this old soldier needed, and it's ready to roll.

Every Color of the Rainbow, so long as it's Magenta or Cyan

So, I've branched out a little.  A schoolteacher friend of mine found a couple of classic Sinclair computers buried in the cupboards at his school:  A ZX81, and a 48k ZX Spectrum+.  The ZX81 was missing a power supply, and the Spectrum was missing nothing, but the keyboard wasn't working:  A common complaint in old Speccies.

Here's the thing.  I have a not insubstantial collection of old Speccies in various states of "not working", including a Plus and a Sinclair 128, both of which use the same keyboard, so I figured we'd be able to get both going in maybe an hour or so.

No.  Ha.