In October 1984, Sinclair released the Spectrum+ 48K which was exactly the same machine, but with a better keyboard (with proper moving keys) and a reset switch on the left side.
So identical were the inners that upgrade kits were offered allowing the owner to remove the main board from their current spectrum and transplant it directly into the new Spectrum+ case.
However, not everyone liked the new style case (directly inspired by the Sinclair QL) - the key legends were in plain black and white making it difficult to remember the various key combinations which had to be pressed for the BASIC keywords.
The colour coding on the rubber keyboard model made this very easy once you had got the hang of it.
The case also had two adjustable feet at the rear so the Spectrum could be tilted upwards to a more convenient angle for typing.
However, the old Sinclair cost-cutting was still there (though hidden). It wasn't a true professional keyboard as it used the same technology as the rubber key version before it - with keys (this type injection moulded plastic) resting on top of a membrane.
Problems and Issues
The main boards in the Spectrum+ are the same as those in the rubber key version from Issue 3B onwards, so all of the issues affecting the earlier spectrum are still present in the Spectrum+.
Even the early problems of the Issue 1 and 2 boards may still appear as kits were sold to allow owners to upgrade their rubber key Spectrums themselves, so the original boards were transplanted.
See the Technical Information page for the Sinclair ZX Spectrum 16K & 48K for further details.
Loose Cassette Connector Sockets
Another very common problem with all Spectrums using cassette leads are loose clamps inside the connector sockets.
This causes the leads to slip out of the socket, or move around affecting program loading or saving performance.
I usually have spare sockets in the Sinclair Sales pages of this Sinclair section of the website, but if your soldering skills aren't up to removing the old and fitting the new then a gentle push with a small flat blade screwdriver is often successful in re-tensioning the spring contact.
The keys on the new "professional" keyboard suffered the usual Sinclair quality problems and tended to fall off very easily. I usually have spares if you need them.
There is a high membrane failure rate on early models too - as high as 35% in the first 6 months as compared to 5% on the rubber ley model, so don't be surprised if you pick one up on eBay to find a non-working keyboard or groups of keys.
Keyboard membrane problems are probably the most common of the Spectrum+ faults and fortunately one of the easiest to put right. Unfortunately though, new membranes are expensive as they are larger and much more complex than the previous model's equivalent. Getting them manufactured these days in sensible numbers is not easy. There are a few people selling them, but quality is very variable - mine are very good (of course), but others, (especially those from Poland) are poor and I have had a lot of Spectrum+'s with new membranes sent to me for replacement.
Splits in the keyboard bubble mat can also cause similar problems, but the most common issues from worn out bubble mats are "spongy" feeling keys, or keys which do not spring back to where they should be (usually a fault caused by too many games of Daley Thompson's Supertest!).
New keyboard membranes and occasionally , bubble mats and keyboard assemblies themselves are usually available in the Sinclair Sales pages of the Sinclair section of the website and fairly easy to fit provided you have patience.
Detailed instructions on how to replace the membrane and/or bubble mat can be found in the Repairs & Servicing pages of the Sinclair section of the website here.
Be very careful when taking the cases apart for whatever reason - the case assemblies were made in various locations around the world with different quality plastics. Many are very soft and stripping the thread of the mounting posts when re-assembling is very easy indeed.