Hi "kach22i"
Yes, I renewed the tuner, a friend, on forum provided me with the service manual, which facilitated the upgrade.
About the upgrade, I intend only FM. So I deleted the AM tuning block. The three power supplies (+ 12V; + 5V and + 27V) have been changed: The muting circuit has been eliminated, because it impairs the sound quality).
The (front-end) was modified, the first stage amplifier Jfet (2SK168), is now a double gate mosfet, BF981, I have the advantage of having better gain and a very low noise. All electrolytic capacitors have been replaced. The ceramic capacitors were replaced by the MKP 1837 from vishay and some from Wima.
In the path of the audio signal, the electrolytic ones were replaced by the conrad jonhson, with the help of a new PCB. In the MPX equalization the capacitors were replaced by mica of cornell dublier.
All resistors were replaced by metal film... Vishay, Welwin and Philips (NOS)
The RCA connectors have been replaced by XLR, as well as the feet.
The antenna terminal with the help of a new pcb, now has an F 75 ohm connector, but I decided to keep the terminals balanced 300ohm
After calibrating, I used some tuners as a comparison, including the classic and rare NAIM nat 01. I confess that it surpassed all my expectations, especially when it is with classical music in my favorite station...
jon
ps: as soon as possible I put photos here.