Philips Philitina B1D43A

1964

Condition and performance:

	Cabinet:	90%
	Reception AM:	80%
	Reception FM:	70%
	Sound Quality AM:	75%
	Sound Quality FM:	75%

Features:

	P.U. Entrance:	No
	Tape Recorder Entrance:	No
	Extra Loudspeaker Output:	No
	Loudness:	Yes, bass and treble
	Treble Control:	Yes, continue
	Bass Control:	No
	Tone Register Switches:	No
	AM Bandwidth Switch or Control:	No
	Tuning Indicator:	No
	Build-in Antenna:	No
	Build in Ferrite or Window Antenna:	Yes, MW
	Separate AM/FM tuning:	Yes

Technical Specifications (Partially measured):

	Tubes:	ECC85, ECH81, EBF89, ECL86, EZ80.
	Wave Bands:	MW, FM from 87.5 - 104 MHz
	Intermediate Frequencies (IF):	460 kHz, 10.7 MHz
	Loudspeaker:	AD 2460/06
	Resonance Frequency Fs:	115 Hz
	Frequency Range Power Amplifier:	?
	RMS Output Power at 4 Ohms:	2 Watts
	Cabinet:	Plastic, grey
	Dimensions:	30.5 x 18 x 17.5 cm
	Mains Power Voltages:	220 Volts~
	Mains Power Consumption	35 Watts
	Retail Price	DM 265,00

Description:

The Philips B1D43A is a small radio with a surprising good performance. It has no features and is just only a radio for use as an extra radio in the kitchen, office or bedroom. IT is a full tuba radio, but the metal chassis is now a Printed Circuit Board (PCB).
The FM detection is a ratio detector, done by 2x AA119 Germanium diodes.
The power suplly is directly taken from the mains power. Only for the 6.3V~ heater supply, a small power transformer is applied. This reduces the heat of a dropper resistor and the power consumption is also much lower.

Repairs:

Mains switch is defective and is replaced by a switch from a worn out Philips potentiometer.
Decoupling capacitor of 125 µF of the ECL86 is removed.
Reason: Reduction in amplification gain due to the today's stronger audio modulation on the FM and AM bands.
Cathode capacitor of the ECL86 of 150R is replaced by 180R 3W.
Reason: Less current of the ECL86, longer lifetime of the ECL86 as well as a more stable operation. It reduces also the 50 Hz audio hum.
It prevents also positive grid voltage of the ECL86 in the future.
Loudness capacitor 100 pF of the treble loudness function is removed.
Reason: too much lost of the high audio frequencies when playing loud.
Capacitor 4700 pF of the output transformer is replaced by a series network of 10K 2W and 1000 pF 1000V.
Reason: Compensate the lost of the highest audio frequencies. The load impedance on the pentode of the ECL86 becomes also more flat.
IF circuits of 10.7 MHz are aligned.
Reason: Improved sensitivity of the FM broadcast stations.

Later I found out the silver layer of 2 FM trimmer capacitors has vanished. This must be fixed in the future. Now the optimal sensitivity is at 95 MHz.

Performance:

After repairing and making some small modifications, the sound quality of this small radio is well and the reception of FM and AM broadcast station is good.

Disclaimer:

The build in power transformer is only meant for the heater voltage of 6.3V~. The high voltage supply is directly taken from the mains power, which means the radio chassis carries the 220 Volt~ mains voltage, which is very dangerous. Before making any repairs on the radio or playing the radio without the back plate, use a safety transformer with separate windings. The insulation of the windings must withstand at least 4000 Volts AC as well as a low leakage current of 0.5 mA~ or less.

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