Hello everybody, I just received a Kenwood CP-D3. I bought it because of its similarity with my beloved AIWA HS-P303 and also because it is in very good condition. Once again, the seller told me: "yes it is fully working with no sound problem". And once again, when I received it, it didn't work. Same problem as I had with my Aiwa HS-P303: no sound even at max volume. But when I plug it to an amplifier, then I can hear the music. It is very low but I can hear it. However there is a difference with the AIWA: when I switch the Dolby on, there is a "buzz" sound even at low volume in the headphones. I wonder if changing the capacitors will be sufficient this time or if there is an additional problem with this device. What do you think ? [GALLERY=media, 1810]AIWA HS-P303 vs Kenwood CP-D3 by Mighty Mightor posted Sep 3, 2021 at 7:33 PM[/GALLERY]
Given how similar the 2 walkmans look on the outside, I believe the two are, in fact, identical in terms of the mechanism and electronics and only the outer case is different (re-designed for Kenwood). Probably AIWA made the walkman for Kenwood: it's something that was practiced back in the day and is still practiced nowadays; and it's not even limited to audio equipment, it's practiced in smartphones, computers, cars, you name it. When a market is large enough, a lot of new companies appear that buy the device "off-the-shelf" and just personalize it with their logo and other details and sell it. Other times, even if the company is already in that business (like in the case of Kenwood), the R&D cost of developing a product from scratch might not justify itself. I came across this video that explains why everybody is making true wireless earbuds nowadays: Why everybody is making earbuds - YouTube The difference that you mention with the Dolby on buzz can be explained by the following: the AIWA had bad capacitors in the Dolby circuit as well, while the Kenwood might have only the output decoupling capacitors leaky. There is a possibility that the capacitors leak after voltage has been applied to them (unit has been used), so there is a possibility (although small) that the unit was working when the seller tested it and it's not working now. This is one of the reasons a seller must be aware of problems like these and test a unit for longer than a few minutes before drawing conclusions. If you put a picture with the PCB (component side), I can tell you if the leak is recent or has been like that for years. The answer to your question is no, unlikely to be other problems. ICs only go bad from reverse polarity or higher voltage than the spec, which on a unit powered only by batteries almost never happens. And it's usually the motor governor IC that burns first from a situation like that, not the audio pre-amp/power amp or Dolby chip.
The last couple of models of Sony DVD reorders were made by Pioneer. Due to a bigger dealer network the Sony ones are far more common than the Pioneer ones here. If you go into the service menu there is actually a P / S setting to set the on screen menus to Pioneer or Sony !
Thank you for the video. Very interesting. It's incredible how cheap some bluetooth earbuds can be compared to their public selling price. No doubt that AIWA made the CP-D3 for Kenwood. Now about this unit, I'm pretty sure the seller was honest and did a short sound test. But after so many years unused, something might happen during this test (capacitors leak after voltage has been applied, as you mentioned). He refunded me partially. Here are some pictures of the PCB (and more)...
Upon close inspection, the leakeage is similar to what it was on your AIWA. Not quite as bad, but pretty bad. There is so much corrosion that the leakeage cannot be something recent, so the seller either tested it a long time ago and assumed it to be working (since it probably was working sometimes in the past) or just lied. All the capacitors need replacement and there is a possibility that some of the traces are damaged and will need repair. The volume potentiometer will need a thorough cleaning and probably the 3 trimmer pots (Dolby levels and motor speed) as well. After that, tape speed and Dolby levels will need readjustment. For reference, the Dolby levels on this unit must be 100mV RMS @ 200nWb/m ANSI.
Well, another complete and detailed diagnosis. Thank you @Valentin. It's time I stopped buying so-called functional Walkmans.
I totally agree with you on "so-called functional walkmans". The problem is this happens on walkmans that are much more expensive (like a D6C or TCD-D7 DAT). In my view, old walkmans should be treated similarly to an old car: if a 30 years old car is to be sold (let's say it's a rare model and it's meant to be drived only occasionaly), the seller can't just say it's working and ask a fortune on it. Everything that's rubber will have degraded, starting from tires and ending with belts and gaskets. Each fluid needs to be changed, even if the specific system does work (like power steering fluid, transmission fluid, coolant, brake fluid). If one buys such a car, it shouldn't be a surprise if the brake pedal goes all the way to the floor when you need it most or the power steering is not working anymore after a few days. Or if the timing belt breaks and the engine stops in the middle of the road with bent valves. It's not really that different when it comes to tape machines. Some have more problems than others, but most will need some kind of service. Some of the late 90s/2000s ones might need just a new belt and a good cleaning, while others like SONY DD series, D6C, D3, etc. will require a complete service.
