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Receivers
  
ICF-SW1
Miniature short-wave receiver - under construction

ICF-SW1 is a miniature LW, MW, SW and FM receiver, also known as a travel receiver or a world receiver, made around 1988 by Sony in Tokyo (Japan). Although these receivers were available on the civil market, they were also used by spies and agents for reception of Numbers Stations.

The receiver measures just 11 x 7 x 2 cm, and weights no more than 225 gr, batteries included, making it one of the smallest in its class. The radio is powered by two internal 1.5V AA-size dry batteries, but can also be powered by an external 3V DC source. By using an (optional) cable, it can also be powered by a car battery.

The image on the right shows a typical SW1 ready for use. It is suitable for the reception of narrowband and wideband AM and FM signals, but not for Single Side Band (SSB) signals, which is regarded by many as a serious shortcoming.
  
Sony ICF-SW1 receiver

Nevertheless, the radio is most suitable for travellers, for example for the reception of the (BBC) world service on the short wave radio bands. Likewise, the sensitive receiver was loved during the Cold War by spies and agents, who used the short waves for the reception of coded messages, broadcast by the mysterious Numbers Stations. The SW1 was succeeded in 1994 by the SW100.

Hard plastic storage box Sony ICF-SW1 in storage box ICF-SW1 in soft carrying case Sony ICF-SW1 receiver Rear side ICF-SW1 with carrying strap and telescopic antenna partly out Holding the ICF-SW1 in the hand Wide range antenna AN-101
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Hard plastic storage box
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Sony ICF-SW1 in storage box
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ICF-SW1 in soft carrying case
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Sony ICF-SW1 receiver
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Rear side
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ICF-SW1 with carrying strap and telescopic antenna partly out
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Holding the ICF-SW1 in the hand
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Wide range antenna AN-101

Controls
The diagram below gives a good overview of the various controls and connections of the SW1. As the radio has controls at all sides, we are showing it here upside down. Most of the front panel is taken by the keypad and the liquid crystal display (LCD). At the left is a high-quality speaker.

Overview of controls and connections on the ICF-SW1

The (green) slide switch at the top is the main power control. Once enabled, the ON/OFF button has to be pressed to activate the receiver. Note that the volume control is at the rear, but can be operated from the right. If necessary, an earphone can be connected to a 3.5 mm jack socket at the right side. Additionally, a (tape) recorder can be connected to a similar socket at the left side.

Controls Front view Right side Top side Volume control
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Controls
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Front view
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Right side
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Top side
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Volume control

Versions
Due to legal restrictions in some countries, Sony produced different versions of the ICF-SW1. The version can be determined by examining the text printed above the LCD display. It shows the FM and AM frequency range supported by this version. The following versions are currently known:

Type AM FM Remark
1 150 - 29,995 kHz 76 - 108 MHz Export version
2 150 - 26,100 kHz 87.5 - 108 MHz German version
3 150 - 29,995 kHz 87.5 - 108 MHz European version
4 150 - 285 kHz + 531 - 26,100 kHz 87.5 - 108 MHz Saudi Arabia


Accessories
Storage box
Box
Soft carrying case Carrying belt Power supply unit (3V)
PSU
Wide range active antenna AN-101 Antenna controller (for AN-101) Earphones Operating instructions
Storage box
The Sony ICF-SW1 was delivered in a hard plastic storage cassette, of which the bottom half contained the radio and all accessories, whilst the operator's manual was held in the top lid.

The image on the right shows the bottom half of the storage case. At the front left is the wide range active antenna, with its telescope antenna stowed along the front edge. At the rear is the mains adapter. An adapter plug is available to allow it to be connected to US wall sockets as well. The radio itself is at the front right.
  
ICF-SW1 in storage box

Carrying case
To protect the radio from dirt and dust, it was usually carried in the soft wallet shown in the image on the right. It also protected the display against scratches.

Note that the wrist strap is attached to the radio, rather than to the wallet. The plastic clip at the end of the wrist strap can be inserted at the back of the radio, to allow its control panel to be tilted when placed on a flat surface (e.g. a table top).
  
ICF-SW1 in soft carrying case

Carrying belt
A larger carrying belt was supplied to allow the large plastic storage box to be carried on the shoulder. It can be attacked to the metal brackets at each side of the box.

The carrying belt is identical to the one that was supplied with the ICF-PRO70 and ICF-PRO80.
  

Power supply unit
The radio is powered by just 3V DC, which can be delivered either by the internal batteries (two 1.5V AA-size penlight cells) or by the external power supply unit (PSU) shown in the image on the right.

When using an alternative PSU, please note that – like most other Sony products – the centre pin of the connector carries the (-) rather than the (+) terminal.  view connection
  
Mains adapter (3V DC output)

Wide range antenna   AN-101
In order to receive much of the short wave radio band activity without the need for a cumbersome outdoor long wire antenna, the ICF-SW1 came with an active antenna, consisting of a wideband amplifier and a telescope antenna.

When using the active antenna, place it as far away from interfering domestic appliences as possible. When in a quiet place, an active antenna should provide a similar signal strength to an outdoor long wire antenna.
  
Wide range antenna AN-101

Antenna controller
When using the wide range active antenna described above, the small control box shown in the image on the right has te be connected between the AN-101 antenna unit and the radio.

The controller is not only used to turn the AN-101 on and off, but also controls the -20dB attenuator. Furthermore it is used to select the desired band (SW or LW/MW).
  
Antenna controller

Earphones
In normal use, the ICF-SW1 delivers its audio to the high-quality built-in speaker, at the left side of the front panel. For descrete operation, a pair of earphones can be connected to the 3 mm stereo jack at the right side.

The earphones shown in the image on the right were supplied with the ICF-SW1, but any other type or brand of (similar) earphones can be used as an alternative.
  
Earphones

Manual
The radio was supplied with an extensive user manual, commonly in multiple languages (depending on the area in which the radio was sold). It contains full operating instructions and suggestions on how to make best use of the radio under varying circumstances.

The manual was usually stowed in the 'pocket' of the lid of the hard plastic storage box, as shown in the image on the right.
  
Manual stored inside top lid of storage box

Hard plastic storage box Sony ICF-SW1 in storage box ICF-SW1 in storage box Mains adapter (3V DC output) Mains adapter plug (for US wall sockets) Antenna controller Wide range antenna AN-101 Telescope antenna with knee-joint
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Sony ICF-SW1 in storage box
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ICF-SW1 in storage box
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Mains adapter (3V DC output)
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Mains adapter plug (for US wall sockets)
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Antenna controller
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Wide range antenna AN-101
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Telescope antenna with knee-joint




ICF-SW1 interior (plastic frame with three PCBs)

Interior
Getting access to the interior of the ICF-SW1 is not difficult, but requires patience and accuracy, as the entire construction is rather small. The rear case shell can be taken off by removing three screws from the rear: two long ones that are clearly visible, and a third that is hidden under the silver volume knob. Pull-off the knob and remove the plastic self-adhesive foil and the screw.

Now use your fingernail to slide through the rig between the two case halves. Eventually the rear case shell should come off. Inside the radio is a black plastic frame that holds three the PCBs.

The frame is held in place by four screws: two in the battery compartment and two that also hold the telescopic antenna. Remove these 4 screws. Also remove the L-shaped black plastic isolation to the right of the centre and desolder the black and grey wires underneath it. The grey wires are connected to ground, whilst the two black wires go to the speaker. They have to be refitted later.
  
Frame removed from the front case shell

The largest PCB (i.e. the one that is visible when the rear cover is taken off) is the main board. It holds the actual receiver that consists of various RF, IF and AF sections, and has components at both sides. The two other boards are smaller and hold the keyboard and the control board. Turn the plastic frame over to take a look at the keyboard. It is held in place by three small screws: two at the lower edge and one at the right. Remove these screws and fold down the keyboard PCB.

Be careful as a small 90° PCB is soldered to the top of the keyboard. It holds the push-button of the light switch. After lifting the keyboard PCB, the control board is exposed. It is held in place by three small screws: two at the right (at either side of the flex wiring) and one at the lower edge (to the left of the flex wiring at the bottom).

After removing these three screws, the control board can be folded away and the upper side of the main board is revealed. The control board is connected to the main board by means of flex wiring that ends in a socket on the main board.
  
Main board (inner side)

If necessary, the control board can be disconnected from the main board. This allows repair of the main board, which — after 30+ years — is most likely to be necessary, as the board contains bad quality electrolytic capacitors that will be leaking by now. Detailed repair instructions below.

Frame removed from the front case shell Frame with main board up Rear side Front side Three PCBs Keyboard PCB folded out Control board folded out Main board (inner side)
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Frame removed from the front case shell
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Frame with main board up
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Rear side
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Front side
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Three PCBs
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Keyboard PCB folded out
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Control board folded out
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Main board (inner side)

Restoration
Bringing an old ICF-SW1 back to life can be difficult. Like many other Sony devices, the SW1 seems to have a built-in lifetime, causing the device to stop working after a number of years. In this case, the limited lifetime is caused by a large number of bad quality electrolytic capacitors.

The problem is typical for electronic equipment that is built in the 1980s and 1990s and is also encountered with other brands of the era. Due to a problem with the chemical substance (the so-called electrolyte), they have a tendency to start leaking after a number of years. The electrolyte then disappears into the radio and the capacitors lose their capacity and, hence, their function.

With the ICF-SW1, all electrolytic capacitors are affected by this problem. The result will be the absence of an audio signal or, in some cases, a very soft or unstable or cracking audio signal.
  
Capacitors replaced by ceramic alternatives

The problem can be fixed by replacing all electolytic capacitors, both on the RF board and on the audio board. Even if your radio appears work fine, it is recommend to replace these capacitors as they will eventually leak chemicals into the radio, which might cause (irreparable) damage. The image above shows part of the RF board on which the electrolytic capacitors have been swapped. Note that we have replaced all of them by modern high-quality long-life ceramic alternatives.

Main board (inner side) Close-up of the bad capacitors Capacitors replaced by ceramic alternatives
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Main board (inner side)
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Close-up of the bad capacitors
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Capacitors replaced by ceramic alternatives

Connections
Power socket
The receiver can be powered by internal batteries (installed at the rear), but also by an external 3V DC power source that can be connected to the power socket at the right side. Note that the (+) terminal is connected to the sleeve, which is different from most other domestic equipment.



Technical specifications
  • System
    FM: Superheterodyne, AM: dual conversion superheterodyne
  • Frequency
     See versions
  • Antenna
    Built-in ferrite antenna, built-in telescopic antenna, active antenna
  • Output
    250 mW (8Ω)
  • Recording
    0.775 mV (-60dB), 1000Ω (mini-jack)
  • Headphones
    18 Ω stereo (mini-jack)
  • Power
    3V DC from batteries or external source
  • Batteries
    2 x 1.5V AA-size penlight (12 hours)
  • Dimensions
    118.2 x 71.4 x 23.7 mm (including parts and controls)
  • Weight
    230 grams (with batteries)
Supplied accessories
  1. Not with Australian model.
  2. Not with UK model.

Documentation
  1. ICF-SW1, Service Manual
    Sony Corporation. 9-953-088-11. February 1988.

  2. ICF-SW1, Service Manual (revised)
    Sony Corporation. 9-953-088-12. December 1988.
References
  1. Martin Bösch, Sony ICF-SW1
    Retrieved October 2017.
Further information
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Crypto Museum. Created: Thursday 05 October 2017. Last changed: Wednesday, 01 November 2017 - 23:06 CET.
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