'Convertible' 405-line sets
Further to the recent discussion about the Philips Twinline 'convertible' 405/625-line receiver in the suppliers section (no longer available) I found this snippet in the article "Converting the Convertibles" in the February 1964 edition of Practical Television:
The rest of the article can be found here: http://www.americanradiohistory.com/Arc ... 964-02.pdf
The sentence about the contacts lining up when the 625 strip is screwed down gave me thoughts of intermittent faults in its future use.
Great pictures, thanks Till
I wonder if substituting frame-grid valves would have cured the low-gain problem?
The IF amplifier valves are EF183 and EF184. A three stage amplifier would have been better. The Thorn add on 625 unit was the same, just two frame grid valves. A transistor IF pre amplifier was available from the service department, this little unit really improved matters.