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AF/RF Oscillator SBC 521

AF/RF Oscillator SBC 521; Philips Belgium (ID = 1728046) Equipment AF/RF Oscillator SBC 521; Philips Belgium (ID = 1728081) Equipment
AF/RF Oscillator SBC 521; Philips Belgium (ID = 1728082) Equipment
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AF/RF Oscillator SBC 521; Philips Belgium (ID = 1728046) Equipment
Philips Belgium: AF/RF Oscillator SBC 521 [Equipment] ID = 1728046 800x541
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For model AF/RF Oscillator SBC 521, Philips Belgium (Belgien):
View showing good quality aluminium case and three-position handle.
Country:  Belgium
Manufacturer / Brand:  Philips Belgium (Belgien)
Year: 1980 ?? Category: Service- or Lab Equipment
Semiconductors (the count is only for transistors) 15: MC1468 BB212
schematic requested
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 110; 127; 220; 240 Volt
Power out
from Model: AF/RF Oscillator SBC 521 - Philips Belgium Belgien
Material Metal case
Dimensions (WHD) 275 x 190 x 260 mm / 10.8 x 7.5 x 10.2 inch

9 frequency ranges 0.1 - 120 MHz. AM/FM modulation with 1 kHz. 

Output: Impedance 75 Ohms; max 30 mVrms: Attenuation 0 - 80 dB continuous.

Employs 16 IC's. 

Net weight (2.2 lb = 1 kg) 3 kg / 6 lb 9.7 oz (6.608 lb)
Source of data - - Manufacturers Literature
Documents about this model
  SBC 521 Service Manual courtesy of member Richard Toy 1518 KB

Model page created by Antonio Barros-Regada. See "Data change" for further contributors.

All listed radios etc. from Philips Belgium (Belgien)
Here you find 320 models, 298 with images and 159 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.


Forum contributions about this model
Philips Belgium: AF/RF Oscillator SBC 521
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philips: SBC 521; AF/RF Oscillator
John Sykes

Recently fixed one of these; unable to find any support documentation or schematic. 

Internally there are two single-sided pcb's: the top one is mainly the analogue circuitry+ PSU regulators, the lower digital + reference crystal + back-up memory battery.

The VCO is based around a Motorola chip type MC1648P, tuned using a BB212 varactor diode. The frequency ranges (9) are selected by a bank of inductors, individually switched by reed-relays. Note that one end of every reed relay and each inductor, ( including the inductor metal screening can) is permanently connected to a reference bias voltage pin on the MC1648, (circa +1.6V).

I found one electrolytic capacitor (1u5 @ 63V)  inserted with the wrong polarity (manufacturing error). One reed had leaked air and was not switching correctly.  

Main regulated DC power-supplies are +/-15V and +5V. The mains transformer is permanently powered, the front panel ON/OFF is a four-way toggle which switches the low-voltage ac secondaries of the transformer.  


Philips Belgium: AF/RF Oscillator SBC 521
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