Page 4
Transistor Radios 1970's and On
Japanese Brands accelerated importing parts, assemblies and finally made entire radios in other countries. Like many American companies they often saved their top of the line products to be made in their country. For a while Hong Kong was a strong competitor to take business from Japanese. However most of these HK companies were garage operations or import/export companies. The mid to late 1970's saw the rise of Taiwan, Indonesia and Malaysian production of brand names in a large scale. In the 1990's Made in China started to become a common phrase.
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1970s and 1980s Radios
1970s and 1980s Radios
Panasonic RF-503: FM/AM Radio. One of the first handheld Panasonic radios using an integrated circuit. Made in Taiwan. Taiwan Made Radios (Mid 1970's) Left to Right
Panasonic R-1042 High Sensitivity AM Lunchbox Portable (1973?). Matsushita Electric Co LTD, Osaka Japan. This model made in Taiwan. Seven transistors, audio tranformerless and AC / Battery (4 AA cells). An uncommon AM only lunchbox style. By this time AM/FM sets were popular in this configuration.
Very orderly layout. Uses 3 inch speaker. Panasonic made most of their own parts. Power transformer shown at lower right.
Emerson P3766A "Swingmate" AM / FM Portable Radio (mid 1980s). 11 Transistors and LED signal strength tuning. Made in Hong Kong. One of the few name brand radios still using discrete parts during the 1980s. Very clean front panel layout.
Sony TFM-7350W Super Sensitive AM-FM-WB Portable (1972?)Sony Corp, Tokyo Japan. This model made in Hong Kong. AC / Battery. Has unique LED Tuning Light attached to dial pointer. Variable tune WB on back.
Panasonic R1019: 6 transistor AM Radio. Made in Taiwan.
Panasonic RF-1050: FM/AM/TV handheld radio. Made in Taiwan.
Has two stages of IF Amplification. I don't see this design very often in transistor portables that are high sensitivity. Generally they have a tuned RF stage with amplification like the Sony TFM-8000W above. IF stages with extra amplification offer better selectivity and greater noise rejection. This radio has very clear sound with weaker station making it a pleasant to listen. Interesting that the first IF amp is a germanium transistor. All the other transistors are silicon.
LEFT: Cost cutting measures. Emerson eliminated an IF transformer from both AM and FM sections. Noticeable loss in selectivity. Slightly tuned the existing IF stages as well as the RF sections. Got an improvement in both selectivity and sensitivity but definitely inferior to a complete IF section design.
ABOVE: Printed Circuit Board, a common failure of this receiver is cracked solder connections at the on-off switch (at the upper right corner edge). In addition the glue used to prevent the switch mounts from excessive movement need to be redone.
ABOVE: Basically the radio is mounted onto the printed circuit board. BELOW: Weather band tuning control (Left side).
PORTABLES
Panasonic "The Cranford" R-1052 (early 1970's) Matsushita Electric Co LTD, Osaka Japan. These radios were assembled in Malaysia and Taiwan.
A 6 Transistor radio. Panasonic eliminated the input and output transformers. The speaker is a 32 ohm driven by a complementary-symmetry class B amplifier (NPN-PNP configuration) Some of the IF stages are pretuned. Also notice the small white dot on the upper left corner. That is the 2SD902 RF transistor in a surface mount (SOT) configuration. The height of the TO-92 version can interfere with the tuning knob shown. Notice that there is only one IF tuning slug. Panasonic used ceramic IF filters in the model. This set has very good tuning and selectivity.
SONY TFM-8000W (Sony Corp, Tokyo, Japan) Multiband mid 1970s Portable Radio (Made in Japan)
Sony had a long running series of "Supersentive " portables that date back to the early 1960s. This model is all transistor (FET + 16 transistors), FM, AM, PSB and 3 SW bands. Has many upscale features for its time such as large tuning meter, fine tuning, FET RF front end, dial illumination, fly wheel tuning and auto battery/AC switch over.
ABOVE: Lighted Dial
ABOVE: Back of radio has provision for external antenna and time conversion wheel. This radio has a momentary dial light switch.
During this time Sony began to phase out the TFM multibanders in favor of higher end communication receivers and the TFM and TR series would phase into the ICF series as the integrated circuit designs rolled in. Soon Sony and other Japanese manufacturers would start having products made in SE Asia and Taiwan.
During this time Sony began to phase out the TFM multibanders in favor of higher end communication receivers and the TFM and TR series would phase into the ICF series as the integrated circuit designs rolled in. Soon Sony and other Japanese manufacturers would start having products made in SE Asia and Taiwan.
Radios in 1990s
Radios in 1990s
Panasonic RF-1052: FM/AM Radio with LED tuning light and uses FM-AM radio IC. Made in Malaysia.
Mid 2000's Panasonic Asian portable and last US market small radio with tuning light
RFP-150 (BELOW) and RFP-50 (RIGHT). Both made in China.
Compare the tuning frequencies of the AM and FM bands I bought the RFP-150 in Hong Kong because I needed a radio
RFP-150 (BELOW) and RFP-50 (RIGHT). Both made in China.
Compare the tuning frequencies of the AM and FM bands I bought the RFP-150 in Hong Kong because I needed a radio
Panasonic R-1329: AM High Sensitivity. With LED tuning light and uses AM radio IC. Made in China.
PERSONAL PORTABLES
When SONY introduced the WALKMAN series back in the late 1970's the concept of a personal portable was a new fad. A personal portable has no speaker, the user has a set of earphones. This is not new but SONY was able to time the demand for the concept very closely. From there every electronic manufacturer came out with their version. Some were radio and cassette only units, but most were radio cassette player combos.Panasonic RF-10 AM/FM/FM Stereo (1983)
Panasonic
A Japanese multinational electronics company, headquartered in Kadoma, Osaka, Japan. It was founded in 1918 as Matsushita Electric Housewares Manufacturing Works[b] in Fukushima, Osaka by Kōnosuke Matsushita. In 1935, it was incorporated and renamed Matsushita Electric Industrial Co., Ltd. In 2008, it changed its name to Panasonic Corporation. Panasonic offers a wide range of products and services, including rechargeable batteries, automotive and avionic systems, industrial systems, as well as home renovation and construction. (from Wikipedia)
Above: ComponentsBelow: With Carrying Case
Table Radios with IC's
Table Radios with IC's
Panasonic RE-6266 (mid 1980s), FM/AM Compact Table Radio. Made in Taiwan by Matsushita Electric, Japan. Uses integrated circuit for RF and IF stages and another IC for audio circuits. Pretty much a bare bones table set. It wouldn't be too long as table radios would fade from popularity.
Basic but still built with quality! Unlike other sets that skimp on power supply and audio circuits, Panasonic has always made an effort to keep the price reasonable yet be quality performers. Here as always a power transformer is still employed that is large enough to handle circuit. Others makers will eliminate power transformers or use one that is not designed for continuous operation.
Lunchbox Portables
Lunchbox Portables
Still Going Strong!
SONY ICF-36 FM/AM and TV VHF 1990's.(Made in China) AC-Battery (4 AA) The basic style has changed little since the 1980s. In fact the changes over the years are mainly simplification of tuning, switch from C cells to AA cells due to more efficient electronics such as improvements in microchip electronics. These sets have center tuning LED indicator which makes tuning easy.
1980s: TYPICAL SETS
LIGHT EMITTING DIODE TYPE
Panasonic RC-6050 (mid 1980s), FM/AM Clock Radio with green LED display. Made in Singapore by Matsushita Electric, Japan. Uses separate integrated circuits for clock, radio circuits.
This is a great example of the traditional layout of clock radios since the 1940s. Clock on one side and radio on the other. This was one of the last models with that style. Soon after microchips allowed clock radios to be totally integrated and more compact.
ABOVE and BELOW: Very typical layout of controls that dates back to the late 1960s.
VACUUM FLUORESCENT DISPLAY TYPE
Panasonic RC-6115 (mid 1980s), FM/AM Clock Radio with Futaba vacuum fluorescent display (VFD). Made in Singapore by Matsushita Electric, Japan. Uses separate integrated circuits for clock, radio circuits. Has high/low display selection.
ABOVE: LM8368-2H (Sanyo) Clock Chip in the Panasonic clock radio.
ABOVE: BIAS MODIFICATION by adding resistors. Changing the Grid bias improves the display brightness.
Digital Clock Radios
Digital Clock Radios
Always Popular
The first digital clock radios were numichron style, a conventional clock motor with revolving digits. LED's made these radios completely electronic. Clock radios from the beginning always treated the clock separately from the radio, as electronics advanced the clocks started to become integrated with the radio. By the 1990s they became totally integrated and more compact.
1960s-70s ELECTRO MECHANICAL
Admiral CRF-281(Late 1960s-early 1970s) FM/AM Clock Radio. A nice example of an early digital clock transistor radio. Used rotating numbered drums geared for hours, minutes and seconds like the early "numichron" clocks. Very basic clock radio, with only alarm set. Very compact model for this time period (only 4 1/4 inches deep). Made in Hong Kong for Admiral Corp, Chicago.
ABOVE: Night glow operation. BELOW: Inside the clock radio.
1990s: COMPACT and TRAVEL TYPES
Westclox 80199 (late 1990s) General Time Corp, Norcross GA. Compact prison style see through FM / AM LED Clock Radio. Midget (5" W X 3" D X 4" H) size full function clock radio. Has wake up to radio and alarm, snooze button and 59 minute timer for radio. Has battery backup for power failure to keep time.
ABOVE: Two IC's used. One for radio and the other as LED driver and clock. Skimpped on extra IF stages for AM and FM sections, making it difficult to receive weaker stations.
LIQUID CRYSTAL DISPLAY TRAVEL SET
Westclox 47529- Travel FM / AM Clockradio. I got one because it had the look of the typical clock radios of the 1970s and 80's. Measures without stand 1 in high, 2.5 in deep and 6 in wide. This one fits on the palm of your hand. Runs on 2 AA cells.
ABOVE: Cute little light to illuminate the LCD display in low light. Does little to improve viewing.
ABOVE and BELOW: Radio is built around a fm am radio chip shown above. Only two external transistors are used as shown below.
Harmon Kardon 330B Receiver 1970-71
Harmon Kardon 330B Receiver 1970-71
Not really a transistor radio but one of the last all transistor receivers. Harman Kardon (HK) 330 series stereo receivers. Harman Kardon began during the late 1950's at the beginning of high fidelity tube am/fm equipment. Harman Kardon first implemented simulcast stereo by having separate am and fm tuning sections so you can hear the am on one channel and fm on the other channel. From the latre 1950's until the end of the 1960's many station would be am and fm for simulcast stereo. In Los Angeles there was a classical music station was KFAC and they were in am and fm broadcasting the same material for this simulcast stereo. In early 1960's Fisher Radio would incorporate true multiplex stereo which we have today. The model you see below was a high school dream when I got interested in electronics. The HK 330 series was an entry level receiver (20 watts/channel) and Harman Kardon was always you get what you paid for company so extras were few in number yet quality was maintained. The 330 and 330A were all transistor, but in the mid 1970's 330B incorporated one integrated circuit, a Motorola IF amplifier unit. The series ended with the 330C. Today HK is still making high end equipment and computer / auto audio components.
Nice clean layout. On the lower right corner is the only integrated circuit made by Motorola.
BELOW: APR 2024- The audio amplifier section has a lot of electrolytic capacitors. A common problem in the receiver are leaky electrolytics that have to be replaced as shown below. Other areas I replaced are on the AM RF-IF section and FM RF-IF section.
BELOW: APR 2024- The audio amplifier section has a lot of electrolytic capacitors. A common problem in the receiver are leaky electrolytics that have to be replaced as shown below. Other areas I replaced are on the AM RF-IF section and FM RF-IF section.
ABOVE: APR 2024- Evening appearance: Freshened look of receiver
RIGHT: Back Panel ------------------->
RIGHT: Back Panel ------------------->
The late 1960s to 1970s look. Green display when on and completely blacked out when off.
ABOVE: APR 2024: Freshened Look. All incandescent lamps and arrays replaced with LED units.
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