The chassis is almost based around tubes exception for signal parts which are even using first time a TBA750 12V 34mA 5.5MHz limiter/amplifier (PHILIPS).
TBA75OC
TBA75OCQ
LIMITER/AMPLIFIER
The TBA750C is a limiter/amplifier with f.m. detector, d.c. volume control and a.f. preamplifier. It is
intended for 4,5 MHz, 5,5 MHz or 10,7 MHZ. The limiter/amplifier is a four-stage differential amplifier
that gives very good noise and interference suppression. The detector is of the balanced type. The d.c.
volume control stage has excellent control characteristics with a control range of more than 80 dB.
The a.f. preamplifier can drive a triode-pentode output stage or a class-A push-pull transistor output stage.
QUICK REFERENCE DATA
Supply voltage V2_5 typ 12 V
Total current drain Ito‘ typ 34 mA
Frequency to 5,5 MHz
input voltage at start of limiting Vi Hm typ 130 1.4V _
A.M. rejection at Vi = 1 mV 01 typ 45 dB
A.F. output voltage at At = i 15 kHz
at pin 16 V0(rms) typ 2,7 V
D.C. volume control range > 80 dB.
TBA75OC
TBA75OCQLIMITER/AMPLIFIER
The TBA750C is a limiter/amplifier with f.m. detector, d.c. volume control and a.f. preamplifier. It is
intended for 4,5 MHz, 5,5 MHz or 10,7 MHZ. The limiter/amplifier is a four-stage differential amplifier
that gives very good noise and interference suppression. The detector is of the balanced type. The d.c.
volume control stage has excellent control characteristics with a control range of more than 80 dB.
The a.f. preamplifier can drive a triode-pentode output stage or a class-A push-pull transistor output stage.
QUICK REFERENCE DATA
Supply voltage V2_5 typ 12 V
Total current drain Ito‘ typ 34 mA
Frequency to 5,5 MHz
input voltage at start of limiting Vi Hm typ 130 1.4V _
A.M. rejection at Vi = 1 mV 01 typ 45 dB
A.F. output voltage at At = i 15 kHz
at pin 16 V0(rms) typ 2,7 V
D.C. volume control range > 80 dB.
Note the EHT selenium rectifier which is a Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue. With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.
Amazing that this TV set is still using valves in 1976 and incorporating integrated circuits too. Very fascinating! :-)
ReplyDelete