You can read about my findings while briefly checking out an ICFD of the newer variant with narrower IF filter on my receiver review page. Maybe later models were improved in this regard? A partly complete scan of the ICFDS service manual containing 16 of 30 pages can be found in the 'GR' group's files section ; local mirror.
You can also find a complete ICFD service manual online these days. If you need a service manual in paper form, there are various sources that sell 'em. I have mentioned a local one in the misc links section. Opening a D has proven to be not entirely trivial. Here's the trick, as posted on group:. To open my ICFD I loose and remove the two black screws on the L and R top and the two brass screws one in each battery compartment. Then, because of a lip on the right lower side, I open the backside turning it like a page from left to right.
No problem. Furthermore, like with laptops a strong thumbnail is an indispensable asset for loosening latches. I have recently obtained an original of the ICF service manual , and a photocopy of supplement No.
This supplement was issued to cover two updates: additional color variation, and circuit variations to reduce drift of the second oscillator. I believe that this supplement covered the infamous warranty changes which Sony made to the ICF starting late in or early in If anybody has further information, please let me know. The original model was issued in a silver case. A black case was introduced. The following parts were added silver part no. To quote the Sony supplement: "The circuit has been changed to reduce the drift of the 2nd local oscillator and location of some parts on printed circuit board has been changed.
The ICF circuit diagram was re-issued in the supplement. In the original the horizontal position was indicated letter, and the vertical position by number as in an Excel spreadsheet. Five of the ten components which were changed were on the antenna board. The easiest way to tell if one has an original or updated ICF- is to look at R It is on the antenna board just to the left of the top left hand corner of the external antenna socket. It should be possible to tell if it is 33 ohms orange-orange-black-xxx or ohms red-red-brown-xxx.
There appear to be some discrepancies in the manual and supplement which I have for the ICF The original circuit diagram shows R66 connected between the source of Q11 and ground. This is the way in which appears in the cct diagram in the supplement. I checked my non-early ICF- D and it is wired as per the supplement. Looking at the PCB layout, it is not clear to me why this component exists, as it connects between two points on the same PCB track. Having documentation with apparent discrepancies makes tracking the history of the models 'challenging'.
The component changes shown in section 2 appear to have been carried over to the ICFDS along with a small number of additional component changes I shall write a separate note at a later date describing these. In off mode there is working a 3 V linear regulator.
So you can change one of these batteries without loss of memory. He measured If a short circuit to ground occurs at the earphone jack, I guess an overload condition at the switching transistor.
Switch off the radio tone switch to music and hold your ear directly at the loud speker. Can you hear some low noise? If yes, change the damaged Q32 2SB In case of a damaged Q32 there will be no pop-up noise. Via PM, Bernhard told me that he had, among other things, changed the frequency response of the audio amp because originally it was too muffled. A circuit simulation via LTspice had shown the following -6dB points:. You can now download the result here.
All the rest is entirely discrete, with 13 transistors, 1 FET and a bunch of diodes. While having two ceramic FM IF filters and thus good FM selectivity for its day and class, for AM IF there is no more than a CFT class filter 1 ceramic element with two IFTs plus another tuned IFT to be found, making it the equivalent of a 6-circuit receiver in classic radio nomenclature middle of the road level basically and comparable to the later Grundig Yacht Boys or Philips D, but certainly quite good for its size back then.
For a complete restauration, I would suggest a workshop not afraid of working on old radios, or a vintage radio enthusiast if you aren't one yourself. Working with dial mechanics and the like in a very compact set isn't everyone's cup of tea and the speaker may be glued to the front in this one as well. What I would suggest to have done is:. Whether a basic set like this is worth all the effort is quite another matter, of course.
If you want something to actually use on shortwave, I would rather invest some efforts into, say, a well-kept ICF-SW with the usual issues instead. Gain distribution is an important topic in receivers, as it affects both obtainable sensitivity and dynamic range. The ICF proved to be very successful, and soon after the competition brought out a number of similar radios. Sony ICF [7]. This was a peculiar set which allowed using just the radio part, minus the loudspeaker, with headphones — an idea which resurfaced a few years later in the SRF W radio Walkman.
Both are collectibles today. It now used a dual conversion concept on shortwave albeit an unconventional one that isn't as resistant to overload as "normal" ones and received a total of seven shortwave bands with increased band coverage. Selectivity and sensitivity on mediumwave and shortwave also were very good, along with decent overload rejection.
The effective tone control and nice audio section and speaker were taken over from the previous model, and power consumption remained low. All in all, this was a winner for Sony and became very popular around the world, with tourists, journalists and SWLs alike. It was soon challenged by "me too" models from other companies with usually better feature sets and sometimes better, sometimes worse performance the Panasonic RF-B50 and Toshiba RP-F11 a.
Kenwood R come to mind, see The competition , but the 'A remained the most popular choice. Actually it still isn't half bad even today, although it does have its limits in terms of dynamic range and band coverage. Sony ICFA the international model. But Sony wasn't done yet. ICFD [5]. While being pretty much the same size as prior models, this was a full-blown PLL synthesized dual conversion set using a high first IF and FET-based balanced first mixer, with a continuous reception range from longwave kHz right up to kHz shortwave models sold in Germany had to make do without the frequencies above kHz and more importantly without the antenna input, a case for a mod plus FM, and all the goodies like a whopping ten station memories, direct frequency input, and a clock with timer function.
Shortwave could be tuned in 5 kHz with analog fine tuning being available, and as a first, even SSB reception was possible. Back then, this was absolutely unheard of anywhere near this kind of size. At the same time, reception performance also was quite respectable. Nonetheless, these things sold like hotcakes ultimately about half a million and got rave reviews. Since the A remained in production until , Sony now had two real winners.
This radio, being ahead of its time, was built for quite a few years; it saw an internal update by to rectify a few issues, and in the model ICFDS NA: ICF was presented, which was pretty much the same as an updated ICFD with different colors. ICFDS [6]. This was an entirely different radio with digital tuning and a tuning knob using an imitation of an analog tuning dial. However, the performance of this radio was quite poor it did, however, receive a number of bugfixes until early The type number similar to the ICFDS caused quite a bit of confusion, and the similar pricing didn't help matters.
ICF from [1]. With the matching active antenna, it did not need to hide from its larger cousins in terms of reception performance. In , the ICFA was retired in favor of the ICF , a slightly cheaper model that noneless had a larger reception range — it covered the shortwave bands from 60m up to 13m dual conversion , m to 75m or longwave in the L version , MW and FM. A flip-out stand was now featured, if only a small one.
Soon after, in , the small dual conversion analogs were shrunk further — the micro version of the ICF was the ICF-SW20, now measuring only This receiver still tuned in 5 kHz steps on shortwave and had a total of 10 presets, but now allowed selecting two different BFO insertion frequencies for preferred upper or lower sideband reception in SSB, did away with the separate clock and backup batteries and had a flip-out stand on the back.
Thus it still sold in fairly high quantities more than samples in 4 years , if not in the same ones as its predecessors given that there was some stiff competition around now think Panasonic RF-B65, RF-B45 or Sangean ATS ICF-SW from [1].
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