Thanks for the welcome. All work was done by professionals in the audio business, from what I can remember. Very obviously power supply total rebuild, this is the 3rd version which included the externalisation of the transformer. A very good transform has been used cannot remember which, but fairly costly. Also better modern equivalent can capacitor. Capacitors change to Jensen’s copper PIO the output value increased to 1uf, they also needed earthing as there was some RF interference with such big metal caps. Resistors matched were appropriate. Any that the tolerance was out replaced. There have been other things added as you can see from underside, but not sure what is what and what they do. Silver wire throughout. A cryo treated power cord and plug from Missing Link. Better earthling trough out tuner. Pre amp volume/mono circuit removed. The PEC module has been update. Good gold RCA jacks. De-emphasis has been changed to UK spec. Has been totally realigned. The 12AX7 - one is a Mullard 1955 Long Plate square getter and the other an Amperex Bugle Boys 1950's 12AX7 D getter long plate, select red tip. Rectifier tube on power supply is a Telefunken EZ80. The two 6AU6 changed to 1950’s Telefunken. A Telefunken E80CF rectifier tube on decoder board. The EF93’s are Telefunken. The 68Q8 is a Philips/Volvo. The tubes on the IF board on the right hand side have also been changed, but without opening up I cannot remember to what. All these tubes are NOS and pretty much the best in their type.
Performance wise over stock, they are 2 very different tuners although it souls is still the FM-3. To my ears and my set up this tuner out performs every tuner I have ever owned. This includes a Sansui TU-X1, Linn Kremlin, Naim NAT01 and Leak Through line with various decoders. Others have agreed. It has better dynamics, slam and tonal quality then any stock tuner could hope to have, and is by far the most musical tuner I have heard. Sound stage is a smaller then with modern tuner. This loses a bit of the ambient cues that give you the being there sound the some good tuner can achieve. There is still a slight bit of noise, but only when ear is put right next to speaker. Not as quite as a modern tuner with all its filtering. Where it really counts though, this tuner is the dogs.