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Friday, 14 October 2016

NAD 5425 CD player - no display

Just a quick one. This delightful NAD 5425 CD player.



Arrived skipping / not reading discs and no display.


Skipping and intermittently not reading discs was an easy fix, a quick clean up of the optics with an airduster, and very careful cleaning of the lens (DON'T USE IPA HERE! - it can damage the optical coating on the lens. It's easy just to breathe on it, and give it a gentle wipe with something lint-free). That had it playing even the most mangy looking disc!




No display?



Let investigate...

The main board is removed ....









.. and the display cowl removed (there's a couple of screws underneath, and a plastic clip.)












... and an open-circuit incandescent lamp is the culprit...










To improve reliability, and LED and 1K limiting resistor is fixed in place. Note the capton tape to insulate it electrically from the links on the board below. Anode (+ve) is to the right in this picture.

The LED I chose was a wide-angle, warm white LED, which I hope will match the original incandescent lamp closely.







... which is does nicely!














I've not tried these wide-angle LEDs before. They're quite good. These are both warm white examples, although they differ in colour slightly! You can clearly see the focussed "beam" coming from the right hand LED, and the much more diffuse spread of light from the left hand "wide-angle" LED.





Job done. Another saved from landfill!


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27 comments:

  1. Unknown31 March 2017 at 16:52

    Great post, so nice and clear and concise. Just bought one of these players off of eBAY because it is 'dead'. I'm hoping its just the display bulb!

    ReplyDelete
    Replies
    1. Doz31 March 2017 at 16:56

      Hi John. Another thing that causes these to appear "dead", is dry joints around the voltage regulators... Hope it goes OK! Be safe. Andy

      Delete
    2. Unknown31 March 2017 at 17:02

      Thanks Andy, I will let you know what I find!

      Delete
  2. Unknown19 April 2017 at 12:46

    Well it was dead because both internal fuses were blown! Bulb also gone but before I sort that I need to work out why it does not read the disc! May have bought a bad one!

    ReplyDelete
    Replies
    1. Doz19 April 2017 at 15:40

      How's the soldering round the voltage regulators? Does the mech click-click-click when a disc is first inserted?

      Delete
  3. Unknown21 April 2017 at 10:34

    Definitely at least one bad joint. I have ordered a new laser for £5 so that I know it's OK. Will solder poor joints, fir LED and resistor and new laser and see what happens - awaiting parts as I type!

    ReplyDelete
    Replies
    1. Doz21 April 2017 at 11:48

      ... if that's an eBay laser, best of luck with it. Got sick and tired of sending them back....

      Delete
  4. Unknown21 April 2017 at 14:31

    Actually I went for one from CPC manufactured in Japan rather than China!

    ReplyDelete
  5. Unknown24 April 2017 at 20:57

    Well in an ironic twist I have everything working now except the backlight! Im only getting 0.5v across D505. I have recheck joints around voltage regulators and cant see anything wrong. Sound output is lovely. Play mechanism is spot on!
    Any ideas?

    ReplyDelete
  6. Unknown24 April 2017 at 21:00

    By the way, the reason it didnt read discs was that the prevoius have a go hero had plugged the blue and red connectors back into the main pcb the wrong way round!

    ReplyDelete
  7. Unknown2 November 2018 at 15:00

    Hi my led display is not working. But my bulb connection are different from the one in the picture.

    ReplyDelete
    Replies
    1. Doz5 November 2018 at 10:38

      It's an LCD display. I've only even seen the one type of connection. Either way, replacing it with a wide angle LED should follow the same procedure. Just check polarity first.

      Delete
  8. Somsak6 December 2018 at 11:54

    ใช้รุ่นเดียวกัน อาการเดียวกันจะเปลี่ยนหลอดขนาดกี่โวลล์กี่วัตต์ครับ

    ReplyDelete
  9. Grzegorz31 May 2019 at 13:58

    Working!! super!! Typu my herro

    ReplyDelete
  10. Neo29 March 2020 at 03:01

    I know this post is many years old, but I still got a question for Doz. So, I manage to fix the LED with 1k resistor by reading this post. And the display is ok again. But when I put the board back in its original position. The CD stopped spinning. And it does not count the tracks anymore. It can still eject and mount CDs, but it does not spin anymore.
    I am not sure exactly what made it that way. So any ideas I would really appreciate.

    ReplyDelete
    Replies
    1. Doz29 March 2020 at 14:08

      Close the drawer with no disc in , look at the laser (from an angle, never directly from above) ... can you see the lens move up and down as it attempts to focus?

      Delete
    2. Neo30 March 2020 at 03:37

      Thanks so much for your reply. Yes, the Lens moved up 3 times to look for the disc. If I can entice you to look at some videos from my onedrive, just 5-10 seconds ( https://1drv.ms/u/s!AtTIZDqN4-7KjZ4uRapMyVNq1h_7WQ?e=O3WyZr )

      Delete
  11. Doz3 April 2020 at 18:25

    I do like to be enticed ! OK, that's the laser attempting to focus. Once it achieves focus, it will spin up the disc. That isn't happening. The lens looks a tad foggy. I'd give it a clean first. Just breathe on it, and give it a gentle wipe with the end of a cotton bud, don't use any chemicals on it. Try again. These players also suffer with dry joints around the power supply regulators. Check these too...

    ReplyDelete
    Replies
    1. Neo13 May 2020 at 14:22

      Hi Doz, I have tried all the things you have mentioned. It did not work. I have sent it to the shop I bought it from (2nd hand shop). So they also could not figure it out. I took the Philips CD650 from them. Sounds ok but I have a feeling I might have liked the NAD sound.

      Delete
  12. MB23 February 2021 at 15:10

    Hello

    The bulb in my NAD 5425 CD player has blown. The service manual states the bulb is 15v 60mA. I cannot find one of these bulbs. I have a few questions that I hope you can help with.
    a) Do you know where the original specification bulb can be sourced? b) Can I replace it with a 15v 50mA bulb?
    c) Can I replace it with a 10v-15v x 0.110A (1.3W) bulb

    Regards

    ReplyDelete
    Replies
    1. Doz26 February 2021 at 09:26

      a) No, hence the LED.
      b) I can't see any reason not
      c) I wouldn't. Whilst the supply may be up to it, I'd be concerned about the heat

      Delete
    2. DRMB26 February 2021 at 10:11

      Hello Doz

      Firstly, thank you for the prompt reply.

      I'll give it a try with the 15v 50mA bulb. If that fails at a later date I will try your LED approach. Do you have a link to where the
      wide angle LED bulb and 1K limiting resistor that you used can be purchased and the full specification of these items?

      Regards

      Delete
    3. Doz26 February 2021 at 14:00

      Any 1K 0.25W resistor will do. The warm white wide angle LED came from eBay. Almost anything with that description should work, even from eBay!

      Delete
  13. MB26 February 2021 at 18:41

    Does LED have a specific voltage, current and power rating?

    I think I might need to brush up on my knowledge of electrical circuits. Why is the resistor needed?

    ReplyDelete
    Replies
    1. Doz27 February 2021 at 16:32

      It's not important. The resistor is limiting the current to a sensible level, and the voltage of the LED is fixed anyway.

      Delete
  14. Unknown10 March 2021 at 14:49


    HI, Thanks for the info, my display illumination was out when I tried the machine recently, your hints resulted in me picking these up https://www.ebay.co.uk/itm/2x-NAD-701-705-712-5420-5425-Display-Backlight-LED-Bulb-Upgrade-15V-4-5x15mm-/183371981756 , soldered 2 in place and the display is perfect. I had one mounted high and the other low, nice even light, and a cheap fix Thanks again. Tim

    ReplyDelete