Circuit changes 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. In the original the horizontal position was indicated letter, and the vertical position by number as in an Excel spreadsheet. The component changes were: C3 0. The easiest way to tell if one has an original or updated ICF- is to look at R
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Pros Low noise, good sensitivity comparable to SWG, even a bit better on the low bands Good selectivity Unlike the predecessor, it features a stand on the back, a rather sturdy one at that. This was taken over into all the newer models.
Good frequency stability no LO pulling even on the high bands This receiver has always been a bit underrated, so you can often get one fairly cheap some price range as the predecessor Cons The receiver is not infrequently affected by electrolytic capacitor related failures, which require very good to excellent soldering skills to fix. Antenna tends to getting loose screw — otherwise it seems to be holding up well though 5 kHz steps are a bit coarse, especially for tuning in SSB stations While SSB operation is improved vs.
Back in those days, saving a web page with images still was a non-trivial task that required some editing to get the URLs right, as no browser had a function to do that automagically yet. A review by yours truly has audio noise spectra illustrating filtering action, check it out! This one is more useful if you want to determine electrolytic capacitor placement and polarity on the board, plus it has all the electrolytics marked in the parts list. I have mentioned a local one in the misc links section.
Capacitor related troubles Like several other approx. If these fail, reception, audio and other problems may result. Leakage may even damage the PCBs. The expected result is drying out or leakage. And indeed, bad solder joints seem to be pretty much a non-issue on these Sony sets except for those that see mechanical stress, typically on headphone or DC power jacks.
If you have the skills and feel like it, do a complete recapping, at least as far as the surface mount electrolytics are concerned. If there are any signs of leakage, clean the board as well. The set would certainly thank you with many more years of trouble-free operation. Vogel for a free recapping job. The 1 trouble spot in this receiver are the surface mount electrolytic capactors used.
If some are affected, the others usually are not far behind. All surface mount! With the service docs and the notes provided on this page, they should have no trouble repairing the set provided the main board has not been damaged by leaked electrolyte. Have C replaced by a suitable tantalum or ceramic capacitor; if there only is an electrolytic at hand must be pretty tiny!
This does not appear to be a very common failure. Disassembly guide The service manual is not too detailed and only shows basic disassembly. This kind of repair requires a fine-tipped soldering iron preferably a temperature controlled soldering station , a steady hand and good sight. Experience with surface mount parts is recommended. A scope may be useful in problem diagnosis. Unfortunately for the poor cap, there is no bypass capacitor for it that would work better at high frequencies the converter itself works at 1.
Instead, C, which has pretty high losses at that kind of frequency, has to endure all the ripple by itself, thus getting heated up and ultimately drying out prematurely. C69 is situated near the CX This must not be too large or it will interfere with the battery compartment to PCB contacts. C68 on the ripple filter input may also be worth changing. My attempts with parts more recently qualify as modern art at most - and that was with a suitable microscope.
Incidentally, when the left output channel ultimately decided to stop working a few years later, the set had the remaining surface mount electrolytics replaced in early Audio amplifier cap notes If power-on pop noise occurs, the primary suspect is C, which connects to an amplifier pin for pop noise suppression. Some pop noise under reduced voltages is normal though.
In case of low audio levels, I would turn my attention to C and C Resistances of only several kOhm has been found when probe tips were about a millimeter apart on the PCB. This caused wrong voltages on the varicaps in series with kOhm! At first, not knowing what the real cause was, I replaced the varicaps of the FM-section Sony was so kind to supply me two for free , which helped for some months because I cleaned the PCB as well. Then I only cleaned the area around the varicaps, which also helped.
Finally, when I realized the leakage, I replaced all 23 electrolytic capacitors except the one in the 14V DC-DC converter in the shielded box. This seems to work! No bad FM-reception and unstable tuning anymore. This repair may easily damage your PCB. Do not try to unsolder the electrolytic capacitors, just crunch the capacitors so that you can unsolder the leads individually. Varicap tuning voltage was high 14V due to no VCO output. I replaced the electrolytic capacitor on pin 23 of CX Initial tests were encouraging, showing the varicap tuning voltage was about 8VDC I had played with T10 tuning inductor.
I think this is the fix! And indeed, changing C69 turned out to be the solution to the "no FM" problem. However, you must not choose a capacitor that is physically too large, since then the battery-to-circuitboard contacts may no longer make proper contact. You need to take out the speaker easy , unclip the computer PCB and loosen the interconnecting ribbon cable fussy before you even have a chance to get the main PCB off the chassis.
Beware of the rod antenna wires, you may want to unsolder them their positions can be seen in the service manual. It has served me well for many years, until when I suffered two failures. I thought your readers would be interested in the two failures and the solutions. AC Power Intermittent Symptom: The radio works with batteries, but is intermittently on and off when using the "wall wart" power supply AC power adapter.
Cure: The problem is that the coaxial power plug has gone in and out many times over the years and loosened the jack. Also, it is impossible to go up or down band-by-band skipping the frequencies in-between standard shortwave broadcast allocations. Cure: Open up the radio and soak the Tact switch with contact cleaner or almost pure isopropyl alcohol while pushing on switch repeatedly.
Watch the switch get "better" by using an ohmmeter across the contacts. Ignore the "open" measurement, which could be Megohms a function of the circuitry behind the switch. Keep cleaning and pressing until the "closed" measurement goes down to less than one ohm which means you are now measuring the resistance of the VOM probe wires, not the resistance of the switch. The problem is that the most common buttons have worn out the contacts in the Tact switches.
Perhaps there is a layer of oxide that has developed with repeated use. I used I have not, but I think it is part 0. AGC distribution is, however, a little different from later models. The classic way of solving such a problem is providing a synthesized 2nd LO with finer tuning steps, as it was done in the ICF for example 1st IF It is clear that this requires alignment and may not give the ultimate precision - in fact, on my sample, AM carrier hets vary a little in frequency between "0" and "5" positions maybe The 1st IF filter also needs to be wide enough for a 5 kHz shift to not matter much, but on This can be taken even further, by the way.
Hmm, and all of these are known to exhibit some warbling on SSB
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