I know, mate. But the missing logic is just a pair of TTL chips and a ROM.
My friend, most of +2A Spectrum's actually have the FDD part cut completely away =(
The Spectrum +2A/B and +3 are part of the +5v/+12v /-12 switching power family (as opposed to the classic 9volt internally regulated family)
here is a +2A/B motherboard
I have two +2a's here (one of them is my friend Beaker71's) and they are like the above, also my friend Yorkie4's is the same.
Here is a +3 motherboard
As you can see the entire portion where the Zilog FDC and a smidge of supporting logic has been completely cut away.
Now, some of the later +2A/B Spectrum motherboards were in fact complete +3 motherboards, however they had the Zilog FDC and some supporting logic not installed on the motherboard (probably to save costs) .
Image missing in action
The irony is I was reviewing an image of these boards not so long ago - I shall keep looking for an image.
For the most part the +2A/B motherboards wont have the FDD option available to them, and those that do will require the hard to find Zilog FDC - although I seen replacement FDC's made from a WD1772/3 - apparently Atari ST's are a good source for these chips (*hehehe*)
However the upside of the +2A/B is that it uses the same ROM as the +3, which means you can easily add an 8bit IDE interface by a small very cheap to make adapter (only a 74LS10, BC327, a 100K resistor, a 40 pin IDE header and a 56 way Edge connector) oh an the +3e ROM =)
So to complete the ZX (9 Volt) family (and the post) -
Heres the classic 48K/48K+ Motherboard
Heres the 128k (Toast Rack) Motherboard
Here is the 128K +2 (gray model)
I hope that helps, the +2A/B Spectrum's are very exciting machines to be honest and I am sure that this will make its future owner very very happy.
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