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  • Author Author: shabaz
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Repairing a CQ-VX5500 CD/MD Car Stereo

shabaz

Introduction

I was recently given a car stereo to fix, and it's possibly the most good-looking piece of equipment I've seen in a long while!

I figured I would document the repair project a bit, since there's not a lot of information on the Internet about it, and it's sometimes nice to see device internals.

The video shows the stereo.. the owner clearly has good music taste, the Django Unchained music CD was already inside:

This model was released around 2001 in Japan, and cost about $760 USD when new. There is a D-suffix and a K-suffix version (the D-suffix version is silver).

The MiniDisc Wiki has a bit of information on it.

Connections

The diagram here shows the pinout.

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The connectors and cables were dirty/greasy as expected, and had bad connections. I replaced with Molex Mini-Fit Jr (reviewed here) since I had the crimp tool for that, and they are nice connectors for this application.

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The vehicle uses an ISO 10487 connector and so I attached the mating Mini-Fit Jr connectors to that too. I also made up some test cables so that I could attach a power supply and a speaker or speaker simulator.

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The new connectors did the trick, and the system pretty much worked apart from the MiniDisc player.

MiniDisc Player

The MiniDisc player doesn't function but it may be a fault with the disc I was using. If you've never seen a MiniDisc before, they are really tiny, in my opinion near-ideal storage medium for music before Flash memory became cheaper.

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Although the mechanism works, I reckon the optical components of the MiniDisc player may have dust on them, since the stereo had some dirt inside. I blasted with some canned air, but didn't take this mechanism further apart. Hardly anyone uses MiniDisc anymore so I don't think it's worth the repair effort.

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Japanese FM Band

A more severe issue is that the unit is a grey import, and doesn't support UK FM operation. The tuner is set to the Japanese frequencies. Taking a peek at the circuit board shows the FM synthesiser (Sanyo LC72135), main microcontroller (the NEC chip visible in the photo below), and the FM tuner module (the long metal can partially visible on the right side edge of the photo). 

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There are a bunch of resistor positions that perhaps may select the region, and you can see a bit of flux on the photo where I attempted to solder resistors. Unfortunately I didn't figure it out; with all resistor combinations that I tried, the frequency band did not change. There is a pinhole reset button on the front panel of the car stereo, and I pressed that each time I made a resistor change, but it only seems to reset the device without wiping its configuration.

I suspected that the resistors to change were those that were 0805-sized rather than 0603-sized.

I don't have a schematic, but the ElectroTanya website offered a service manual for the CQ-TX5500, so I looked at that instead. I experimented with the resistors highlighted here:

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A bit more of the schematic from that CQ-TX5500 model (click to zoom):

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The configuration is likely stored in the FRAM chip visible to the right of the NEC microcontroller chip. I could desolder it and extract the contents, but there's only finite time to try to repair this car stereo, and I didn't do this. Even if I succeeded in changing the band in this manner, it still may not work if the VCO connected to the synthesizer chip needs adjustment/component changes. For now, if the owner wishes to use the FM band in the UK, there is the possibility to purchase a cheap band converter device that connects to the antenna socket (the wrong frequency will be displayed however). It's an ugly solution, but it is a solution.

Summary

With a bit of clean-up the car stereo functions adequately. It's a 20-year old car stereo but there's plenty of life in it, it is well made. I just wish Panasonic had published some information to help change the FM band, but it is pretty normal for manufacturers not to do that, since it affects their sales arrangements in different regions. I still need to give it a proper listen, but it sounds great, and looks awesome. This will be returned to the owner soon.

Thanks for reading!

Parents

  • That indeed looks like a very nice piece of stereo equipment.  I have always had a fondness for the Panasonic brand, but lately even high-end manufactures have taken design shortcuts and relaxed standards such that is more difficult to find high-end components with almost reasonable pricing.

  • in reply to genebren

    , I have a different opinion Slight smile.
    I'm a big fan of vintage gear (you should see my living room). But never has there been better consumer audio around then now. 
    Good quality for a price that's in reach for many people.

    In the 70s and 80s, everyone had bad equipment except a minority. Nowadays, good quality gear is available for a mediocre budget. It doesn't look as cool anymore though Slight smile.

    If digital audio has achieved one thing: good audio quality for all. A cheap basic CD player sounded very good. A cheap cassette deck or record player sounded crap.

  • in reply to Jan Cumps

    (you should see my living room)

    correction: you will see my living room
    image

  • in reply to Jan Cumps

    The trends are definitely interesting, I don't have any high-end equipment (I consider your equipment in your photo high-end) it's certainly good that modern digital techniques like (say) DSP can (partially) compensate for lower-cost speakers/enclosures and make them have a higher-end sound quality, whereas in the past you'd need the large wooden (expensive) enclosures and so on. I suppose homes/apartments are smaller too, where would people stick large speaker systems. 

    I get annoyed at the skimping like (say) DAB sound quality which isn't technical but due to very low channel bandwidth, because people think consumers don't want higher quality. Also with FM radio (admittedly analog), where modern FM receivers are low-quality because the digital techniques are used to save on costs, and the older FM receivers sounded better (although they cost a lot more). But the root cause is they are low-quality because manufacturers think or know the demand isn't there, so why make the high-quality product. The balance between cost and performance feels wrong there for me (but I'm sure not for others) but I think otherwise you're right, you can even plug in a phone and get good sound, since digital and other techniques have advanced so much.

  • in reply to Jan Cumps

    I do agree with you.  I may have poorly expressed my opinion.  I too have been a vintage audio fan.  My last turntable was a very nice Bang & Olufsen, teamed up with some nice Kenwood components and JBL studio speakers.  I broke into audio through building a high school radio station studio and through touring many professional studios (also hanging around with some serious audiophiles).  I dreamed of a tube based amplifier (McIntosh) but could afford the Kenwood.

    When I moved in with my wife (many years later), a wall full of stereo was too much, so I sold it Frowning2

    My recent search for a car stereo was an exercise in futility.  The brands that I used to consider as great were now so so (Alpine for example).  The process was so frustrating that I just gave up and am suffering with a messed up stock Toyota Prius stereo that routinely looses its mind leaving most of the controls useless.  I am sure my frustrations are caused by a lack of current knowledge of stereos and stereo manufactures

Comment
  • in reply to Jan Cumps

    I do agree with you.  I may have poorly expressed my opinion.  I too have been a vintage audio fan.  My last turntable was a very nice Bang & Olufsen, teamed up with some nice Kenwood components and JBL studio speakers.  I broke into audio through building a high school radio station studio and through touring many professional studios (also hanging around with some serious audiophiles).  I dreamed of a tube based amplifier (McIntosh) but could afford the Kenwood.

    When I moved in with my wife (many years later), a wall full of stereo was too much, so I sold it Frowning2

    My recent search for a car stereo was an exercise in futility.  The brands that I used to consider as great were now so so (Alpine for example).  The process was so frustrating that I just gave up and am suffering with a messed up stock Toyota Prius stereo that routinely looses its mind leaving most of the controls useless.  I am sure my frustrations are caused by a lack of current knowledge of stereos and stereo manufactures

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