Brief History


About the founder - David Purdie FInstCT


The founder of InvisiTech (formerly PRS) was born in Glasgow and has always had a very strong Scottish identity, despite living in the south and having no accent at all. His education was in Essex, Sussex, and Newcastle-upon-Tyne.

David was apprenticed as Mechanical Engineer (Toolmaker) with Lintott Engineering Ltd in Horsham, manufacturing amongst many other things, the high-power magnets that drive the cyclotron at CERN in Switzerland (now known for its Fast Hadron Collider).

At the other end of the spectrum, the company also made silicon implanters (to make wafers for the IC manufacturing industry) – now that part of the company is Applied Technology.

This was where a large variety of specialist skills and techniques were learned. These have been retained and now are being utilised as part of the mechanical obsolescence solutions.


At the end of the 3-day week there were very few jobs available and David’s desire was to move into design, PCB Design was all he could get, which turned out to be a real advantage later. This was in the days of hand taped artworks designed at 4 to 1 where thinking ahead and advanced planning saved a lot of wasted time. Currently InvisiTech is re-engineering PCBs where this sort of fragile artwork has not survived the tests of time.

With this mix of engineering experience, Singer Link-Miles (the flight simulator manufacturer) made him a production engineer in the PCB and Cable departments. This was a very interesting insight into the workings of a military supply corporation, which has been invaluable in dealing with customer processes.

From the above and a desire to be his own boss - David started Precision Repair Services to repair catastrophic failures on PCBs like burns, warps and damaged copper.   This led into  PCB upgrades and InvisiMod was born.  When electronic obsolescence started hitting the Mil/Aero business, converters were born.

When repair was not the significant part of the business, InvisiTech Ltd was a more appropriate company name. 

Shortly after growing the company, Shirley joined the team and eventually became a director - she stayed playing a vital role, until she retired in November of 2017. She has moved to the mountains of Portugal and started a guest house .

Story of providing Solutions

Owing to his unique background, David was asked by The Component Obsolescence Group & BSI to be the UK representative on the team to write a standard on component/assembly re-use (at the end of the designed life) IEC62309. This work involved travelling around the world meeting with other representatives, each holding their countries view, and with the task of making sure their methods were in the standard. This meant using negotiating and diplomacy skills, which were successful in record time (these things normally take many years), and as a result David was given a certificate for outstanding service to show their thanks. A small story – during the process one country totally objected to the thought of second hand parts being sold as new, they objected to any reference to as good as new (coming from their position in the bathtub curve of working life). Therefore, there was a need to remove the wording that was causing the problem. David thought up a new word for this condition QAGAN. The country in question refused to accept any Acronym or word that had another misinterpretation possibility – so their legal team went away and researched this and came back with no objections as the only use of this was in Inuit. What they didn’t know was he made the word from Qualified As Good As New! However, as he says it’s just politics and the end justifies the means.


To entertain himself in his spare time David has started painting (which he was taught on the QM2 on a Trans-Atlantic crossing). This has built upon a previous history of making stained glass pictures using traditional medieval techniques. He also writes small books that are business and personal development oriented. He feels very strongly that life is what you make it and we are all responsible for our own happiness. He took his into his hands and resides in Florida with his American wife. Together David and Dianne manage InvisiTech from there and visit customers, suppliers and subcontractors in the UK several times a year. 

DO you have a problem of obsolescence or PCB upgrade to resolve?

Ask David to put you on his next visit trip! Call or email and you will receive a reply within 24 hours.

How to contact

David can be reached by calling 01202 233 400 (please keep calls between 12.30pm and 11.30pm) 

or by emailing

Alternatively you can use the contact section on the home page

Looking forward to hearing from you soon.