This particular computer was produced during a manufacturing change between the earlier BBC Micro computers and the later Issue 4 and Issue 7 machines. As such, the BBC Micro is housed in the older design case which has several differences compared to the later design.
The case texture itself is rougher on the older design and these machines can appear much dirtier than their later counterparts over time due to the deeper crevices that can hold the dirt. The branding too was changed for later models to avoid trademark infringement in the United States as the term "BBC" was trademarked by an American company in the US as opposed to the British Broadcasting Corporation here in the UK.
This BBC Micro is relatively unexpanded. It contains the following upgrades.
This BBC Micro was bought through eBay in November 2010. The machine was in a poor state of repair with several sub systems being faulty. It had apparently been stored unprotected in a loft for many, many years and the poor storage conditions had taken their toll. The machine was internally covered in a thin layer of mould and externally was very grubby indeed.
The machine was stripped down and thoroughly cleaned with the case being soaked for several hours before being treated to a deep clean with a toothbrush and fairy liquid. The case was then dried and cleaned again with an antiseptic solution to kill off any remaining mould spores. The motherboard was cleaned with Isopropyl Alcohol, gently removing all traces of mould.
Once cleaned, the machine was rebuilt and switched on for testing and although it powered on and worked, there were many areas of the BBC Micro that had failed resulting in an extensive test programme being carried out to fully diagnose the issues found with subsequent parts being repaired or replaced.
The photo shows the faulty coil (L1) which was stripped and re-wound (double winding) with 980mm of 24SWG Enamelled Copper Wire. The resin needed to be removed a piece at a time using fine wire cutters and pliers to cut off and break up the resin.
The BBC Micro case was designed by Allen Boothroyd
Here are some links to further information and resources for the BBC Micro that may be of interest.