Panasonic RX-DT505 tape mechanism problem

Discussion in 'Chat Area' started by mrn, Dec 19, 2016.

  1. mrn

    mrn Member

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    Hello everybody,
    I got the above dual-cassette boombox with built-in CD-player.
    It arrived in a state when it could not read CDs at all,
    and the tape mechanism (fully electronic) was also doing strange things.

    After taking apart and thorough cleaning the CD part seems to be ok,
    however both sides of the cassette mechanism does the same strange thing:
    - playing in any direction: head engages, tape starts to turn, but immediately stops, releasing the head back.
    - fast-forwarding and fast rewind: sometimes works, sometimes however, normal playback speed is used and the tape head goes into the tape, as if it were asked to play. no sound, though. both sides can reproduce this.
    - recording: does the same as playback, ie head stays not inside the cassette.

    I have checked the belt: all seem to be ok.
    Also, there was not too much dust visible in the tape mechanis.

    the question is: what could cause this strange behaviour?
    thanks in advance!
    Marian
     
  2. Radio Raheem

    Radio Raheem Well-Known Member

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    Hi marian try cleaning all the micro switches with service spray mate, this is normally the culprit, the switches have caps on them that need to be removed first, good luck
     
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  3. mrn

    mrn Member

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    thanks a lot for the hint! i will give it a try and report soon...
     
  4. Radio Raheem

    Radio Raheem Well-Known Member

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    no worries, good luck:)
     
  5. randall977

    randall977 Member

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    Did you sort this out?

    I've just bought one of these very nice stereos, looks unused but cassettes didn't play or FF/RW. I took the whole thing apart, replaced the belts (which looked and felt like new) with inferior quality new ones...but are new rubber! Still it immeiately stopped / very slow FF/RW.

    It now works perfectly, I did two things but I'm not sure which one sorted it.

    1. The cassette transport must be removed to clean the exposed contacts whch engage when you press play (they cannot be reached in situ as they are behind the case plastic). If these have oxidisation then the head will disengage again. They looked good but the contact faces were dark - I used light abrasive on both decks.

    2. The transports have to be removed for this as well. The very small central pulley cog which engages when you press play / FF / RW seemed stiff - I lubricated it. I can't be 100% sure it was stiff but it would make sense why the FF / RW were very slow and it might also cause the cassette to auto stop immediately. This particular component is a very common issue on many later Aiwa and Technics decks.

    Number 2 seems likely as it explains why nothing worked. Item 1 could occur if not used for a long time - damp conditions etc.

    I would thoroughly recommend this stereo - well made, good features and nice sound. No input except for mic is annoying in the ipod era.
     
    Last edited: Dec 24, 2019
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  6. randall977

    randall977 Member

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    A few photos of the twin cassette mechanism used in many Matsushita devices of the 1990's - very nice quality by todays standards - Cro2, metal, HX-pro, headroom extension.

    The new belt kits are useless - stay away from them unless the smaller belts are round - otherwise they come off. I found the original belts on all four of my decks to be in excellent condition in everyway - two decks virtually unused, two well used - belts all very good.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
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  7. kanamaster

    kanamaster Member

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    Hello. I know this thread is already old, but I don't seem to find any better place where to post my request for help.
    I need to open my RX-DT505. I follow the instructions in the service manual and I remove the six indicated screws from the back side. Nothing else is said to be done in order to remove the front cabinet. But I can't. Something is still preventing me from removing it. Can you help me with possible causes? Thanks in advance. Regards.
    (I forgot to say that I have previously removed the handle. Just in case......)
     
  8. Longman

    Longman Well-Known Member S2G Supporter

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    I have never worked on a DT505 but common disassembly problems on other equipment have been
    • Needing to open cassette doors
    • Needing to open CD trays and remove the front trim from the tray.
    P.s Six screws sounds like a low number for such a large box.
     
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  9. kanamaster

    kanamaster Member

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    --------------------------------------------------

    .- I had already tried by opening the cassette doors. Didn't work.
    .- Not tried the second suggestion. I will try it. But because of the design of the whole thing, I don't think this could be the cause.
    I post here a copy of the page of the service manual, where you can see the instructions for removing the front cabinet. Only six screws.
    Thanks a lot for your ideas. Maybe some more come.
     

    Attached Files:

  10. kanamaster

    kanamaster Member

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    By the way, if those two claws appearing on the instructions page are the cause of me not being able to remove the front cabinet, I can't even see them.
     
  11. kanamaster

    kanamaster Member

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    @Longman -- Definitely nothing to do with the trim or the whole CD unit in order to open the fron cabinet.
    Thanks for your suggestions.
    Really hoping that others who might have opened this kind of unit also bring ideas.
     
  12. Radio Raheem

    Radio Raheem Well-Known Member

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    you need to pull very firmly these do not just fall apart with the screws out...

    also verify there are no more screws....forget the manual for the moment

    have done loads of these but not this one

    do you have any experience working on these my friend....if not i suggest you leave well alone bud
     
    Last edited: Dec 17, 2023
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  13. kanamaster

    kanamaster Member

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    I'm certainly not a certified technician. But it is neither my first boombox (or walkman), nor the first I would open for some minor repairs or maintenace.
    I finally found a video (maybe the only one on the whole internet) that shows the opening of the front cabinet of a RX-DT505. It has japanese subtitles. I could understand the subtitles using the translator of my smartphone. I post the link of the video here so yo (and maybe others) can see that there are only six screws to remove on the back side.

    Code:
    https://www.youtube.com/watch?v=Le6FiqQhNek
    Going back to the manual (which you suggest me to forget about for the moment)...... If you take a look at the page I posted before they mention two "claws". I also mentioned them before. The problem is that I cannot find where those two claws are, although they show them in the diagram. But it is not clear to me at all. Maybe with your experience you can guide me to find where those two claws are. In the japanese video I can't see them either.
    Thanks a lot and kind regards.
     
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  14. Mister X

    Mister X Moderator Staff Member

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    Those "claws" can be really strong, sometimes they break. I'm wondering if there's a hole somewhere to get a long tiny screwdriver in to push them down. Otherwise you'll have to force it somewhere, maybe using something like the plastic tools they use on car trim so you don't scratch up the case.
     
  15. Radio Raheem

    Radio Raheem Well-Known Member

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    they are not claws most eggs have them........if you cant get it apart i would seriously forget about it....i have a personal way of dealing with eggs..........if they don't come apart or more importantly go back together i smash them up with a sledge hammer lol
     
    Last edited: Jan 9, 2024
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  16. kanamaster

    kanamaster Member

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    Hello! After some time, back here again.......I need to replace the belts of a second unit I bought (also a RX-DT505). I already have the cassettes mechanism out. Now I need to remove a circuit board which is on the bottom part of the whole mechanism. For this, one of the steps (following the service manual instructions) is releasing some connectors, from which I have already released two. But the others two, which I show in the following pictures, are being a little pain in the neck. I try doing it by the edge that I think is the one they suggest in the picture of the manual. But after trying several times and even with the use of some strength, I'm afraid of being doing something wrong and damage the connectors. Besides, I have also tried on the other edge of the cable, but also with no success. Does anybody know the correct edge I should pull out? The one connected to the geen board, or the one connected to the white board? Thanks in advance.

    [​IMG]

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  17. Longman

    Longman Well-Known Member S2G Supporter

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    Have a fiddle around on the marked connector to see which bits move. To me it looks as if the bare wires at the end of the cable might be gripped into the connector with a latch. A have seen that on quite a few bits of consumer electronics.
     
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  18. kanamaster

    kanamaster Member

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    Maybe you are refereing to something like the ones I show in the picture below? If it is the case, I removed them before trying to release the cables, but as I said before, with no success. And I'm affraid of damaging the solders of the connectors on the board. Thanks for your idea.

    [​IMG]


     
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  19. Radio Raheem

    Radio Raheem Well-Known Member

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    Try pushing down on the clip facing the motor, at the same time gently pull the wires.....I have done these before but dementia is setting in, so be careful
     
    Last edited by a moderator: May 20, 2024
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  20. kanamaster

    kanamaster Member

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    Hello again. Finally I managed to do what I wanted (replacing the belts) without releasing those connectors. Thanks anyway. Your help, ideas, suggestions, are always much appreciated!
     
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