“Issue 1.5” is an unofficial name used to describe an early issue 2 Spectrum incorporating leftover issue 1 parts. Basically, a fancy name for an issue 2 Spectrum that is a bit more special and a bit less common than any normal (later) issue 2.
Apart from using an Issue 1 ULA (5C102E) with the mandatory cockroach modification, early examples also encompass case parts specific to issue 1 Spectrums. Owing to little interest or demand they aren’t as collectable so don’t tend to fetch the high prices actual issue 1 machines command. Hence it could also be called “Poor Man’s Issue 1”.
Another name for such machine I’ve come across is Prototype Issue 2 but that name doesn’t sit well with me so I’ll stick to calling it “Issue 1.5”.
Externally it can be difficult telling it apart from an issue 1 Spectrum, especially when featuring a grey keymat normally associated with issue 1 machines. (Interesting little-known fact: Not all issue 1 Spectrums have grey keymats, and equally a grey keymat isn’t always a token of issue 1 machine.)
Even the serial numbers stamped on the bottom of the case aren’t always conclusive with first issue 2 issue 1.5 machines appearing as early as 15,000 and issue 1’s being spread out all over the place and appearing randomly where you wouldn’t normally expect them to.
It may be a coincidence but none of my issue 1.5’s feature an adjustment hole present on issue 1 cases – it could be a distinguishing element.
Look out for various types of moulds when met with a case embodying an adjustment hole – note the position of the logo:
When in top right corner the case belongs to an early Spectrum
When in the centre bottom it’s a much later production case and you won’t find issue 1 or 1.5 in there (unless re-housed)
The only certain way to be sure what issue is your Spectrum without opening the case is looking through the hole in the expansion port at the rear of the case.
Issue 1: Look for a solitary orange capacitor
16K Issue 1 Rear View
Issue 1 with 32K daughterboard expansion: Lots of orange capacitors inside
48K Issue 1 Rear View
Issue 2: Like a normal issue 2 (the colour of the capacitors may vary)
Issue 2 Rear View
Issue 1.5: Like issue 2 but with visible wires (connecting to the cockroach)
Issue 1.5 Rear View
And here are some hi-res photos of topless Issue 1.5 Spectrums for your viewing pleasure:
What a great Speccy this is (to me, at least). When I discovered this serial number a few weeks ago I was completely lost for words. After so many Spectrums I’ve been through how can there still be anything left out there to surprise?
Found this one in Poland but there might be more in other Eastern European countries too.
Number format apparently same as in certain Sinclair QLs (although I have no evidence for that)
Very dark keys, little signs of use
Issue 2, 48K
This issue 2 board predates the case. The motherboard was made in mid 1983 and would originally belong in a case with a number 001-394xxx or thereabouts. The colour of the serial number (blue) suggests year 1985 so that’s when the board would have been rehoused.
Although the case is featuring the adjustment hole present on Issue 1 Spectrums, the mould is slightly different to the original issue 1 case – the Sinclair Spectrum branding logo is at the bottom of the case (not in the top right corner) and the recess next to MIC/EAR and Power sockets is in rectangular shape (not rounded).
Spectrums intended for American market were required to comply to FCC regulations.
One of the requirements was a shielding used to to eliminate radio interference. Even though insides of some cases were sprayed with conductive paint, the Spectrums were never granted an FCC approval.
This Spectrum was bought new in mid 1980s in Germany – it was made using spare leftover parts (such as the shielded cover), hence why it houses an issue 2 motherboard even though the serial number is one of the latest.