Scalextric Digital Pro GT set - partially working, needs some trouble-shooting

Description

PLEASE NOTE, this set will only be suitable for a Scalextric Digital enthusiast who knows who to troubleshoot and fix things!  The set is boxed, complete and in reasonably good condition overall but is only partially working. Please read the detailed description below before getting in touch - thank you...

Cars - Aston Martin DBR 9, Porsche 911 GT3R, Maserati MC12, Ford GT-R
All four cars work, including their headlights and tail lights. All cars have been well used and crashed often. All four spoilers have broken off, but are included in case they can be reattached. The car bodies are solid, but paintwork is scratched, with some minor parts such as wing mirrors and wipers missing. There are a few minor sticky tape repairs on some cars. The braids/brushes are adequate but could be replaced. 

Hand Controllers and Digital Power Base
There is a problem with the Hand Controllers and/or the Digital Power Base. The blue controller is working normally and works in each of the four connectors (1-2-3-4) of the Digital Power Base. It can be used to operate each of the four cars (one at a time!).
The red, yellow and white controllers do not seem to work. They may need to be taken apart and cleaned or they may need replacing. Or perhaps the Digital Power Base is faulty.

Track
The track seems to be in reasonably good condition - I've tightened the metal connections and cleaned it up a bit.  The metal of the track has tarnished from silver to dark grey and may benefit from a proper clean (it's not rusty). Some of the joints are a bit clunky as the cars pass over.

Lap Counter
This seems to work normally, but please bear in mind I was testing it with one car at a time only.

Supports and Barriers
One of the grey flyover supports is partly broken but seems to hold up the track well enough. All the barriers are fine.

Packaging and Instructions
The box and packaging are in good, clean condition and the box has a plastic carry handle - the box measures 100 x 46 x 14 cm. The instruction and safety information leaflets are all included. The main instruction leaflet was stored separately for no good reason and is yellowed and mottled with age.

Background information, testing and faults
The set is around 13 or 14 years old - it was in use on and off for about two years and has been stored in a cupboard since then. I've taken it out recently to clean, test and photograph it for sale. When I assembled it, it wasn't really working properly so I did some work on the track connections and now the cars run quite nicely. It was frustrating to only get one handle working but I decided I didn't have the time or knowledge to resolve the problem with the controllers and power base. It may be an easy fix for someone with the right know-how and some spare time, or it may be that some replacement parts are needed.

FOR COLLECTION ONLY from SE19, between Crystal Palace and Dulwich.

Ad ID: 1502127104