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Faulty Arcam Alpha 5 CDP (help needed)

Discussion in 'd.i.y.' started by Mike P, Mar 29, 2013.

  1. Mike P

    Mike P pfm Member

    Today I collected a totally standard Arcam Alpha 5 CD player which I intended to keep as a spare for my other Alpha 5 which has received a number of modifications (see my thread in DIY section).

    The player powers up fine but won't read any discs. The turntable motor spins but it won't recognise the disc and after a little while an ERR message comes up on the display.

    Since I have another Alpha 5 I swapped the DAC boards over and the DAC board from the faulty player works perfectly in my other one so I can be sure that the fault is somewhere with the main board or laser/transport assembly.

    Any suggestions? I have a copy of the service manual if anyone needs to see it.

    Many thanks, Mike
     
  2. russel

    russel ./_dazed_and_confused

    Assuming you have cleaned the lens assembly, very carefully! then it could well be the laser, sometimes there is a adjustment for the current and the very early ones had lots of pots for adjusting the servos. If you can increase the current it may start to work but a new laser assembly may be needed they are very static sensitive so be careful playing with it.
     
  3. Mike P

    Mike P pfm Member

    Hi Russel,

    I've just finished performing a laser assembly swap between the two players (observing anti-static precautions).

    The laser assembly from the 'faulty' player doesn't work when transplanted into the 'known good' player so I think it's fairly safe to say that the laser is dead.

    This is the worst case scenario for me as the whole point of the exercise was to source a spare laser for my modified player :(

    The seller (ebay) listed the player as 'working and fully tested'. I guess that's what you get with ebay.
     
  4. RustyB

    RustyB Registered Ginga

    You need to check that the disk actually spins once it's loaded.
     
  5. Mike P

    Mike P pfm Member

    Yes the disc spins freely.

    I know that sometimes the 'platter' can be pushed to far down on the spindle which then jams the motor but that isn't the problem here.

    The CDM9 is a swing arm type laser and the laser is free to swing.

    When you load a disc it spins it a few times then gives an ERR message. Very occasionally it spins the disc for a little while before stopping and then spinning the disc in the opposite direction at a much faster rpm.
     
  6. zener

    zener fluff

    If the laser assembly wasnt held still during transport then it was free to flap about wrecking it. there should have been a clamp inplace to hold it still , failing that a bit of foam.
     
  7. russel

    russel ./_dazed_and_confused

    From http://vasiltech.nm.ru/CD-Player-DAC-Transport.htm


    ARCAM ALPHA 5TDA1541A – SAA7220P/B CDM-9/44

    Find a cheap player that uses the same transport from the website and cannibalise it would be my plan.
     
  8. Mike P

    Mike P pfm Member

    That's an excellent link!

    The ebay seller turned out to be a PFM user. He was a real gentleman and gave me a generous partial refund on the player (thanks Kevin).

    I'm now going to try to find a laser for it. I think a CDM9/44 or CDM9/65 will fit.

    If anyone on here has one for sale please PM me.

    Thanks, Mike
     
  9. 337alant

    337alant Negatively Biased

  10. Mike P

    Mike P pfm Member

    Here's an update for anyone interested.

    Further investigation showed that whilst the optical pick-up wasn't able to read discs any more the laser diode itself was not actually dead.

    After a bit more head scratching I realised that the other lens inside the pick-up was actually dirty. There are two lenses inside the pick up which work a little like a telescope. A small solenoid moves the two lenses further apart or closer together to alter the focus and it whilst the top (external) lens was clean the bottom (internal) lens was dirty.

    This is easy to check on the CDM9 pick-up, simply hold the pick-up up to the light and look through the lens. There is a small reflector at 45 deg below the lenses and you can see through this to the outside world.

    On my good/working pick-up this image appears crystal clear whereas on the faulty pick-up this image was very hazy and blurred.

    Since the pick-up was already not working I decided to have a go at dismantling it to try to gain access to clean the lower lens.

    So armed with the only data sheet I could find (in Chinese I think)

    http://www.partmate.com/download/OPU/CDM9.pdf

    I gave it a try....

    Dismantling the pick is just as desperately delicate as you might imagine. Inside the lower lens was indeed absolutely filthy dirty and the small solenoid was covered in magnetic dust.

    I cleaned the lens and tried to put it back together. I'd love to be able to tell you that I managed it but I'm afraid that I managed to put a small tear the flexible ribbon lead.

    However, the moral of the story is that if you have a CDM9 pick-up which no longer works check for dirt inside the pick-up by looking through the lens assembly. I didn't manage a successful repair this time but having learnt from my mistake I'm reasonably confident I could pull it off successfully next time.

    If you have a old non-working CDM9 pick-up which appears to still have a functioning diode DON'T throw it out. It's well worth having a go at cleaning it! What do you have to loose?

    If anyone has an old pick-up they'd like to send my way (I'll pay the postage) I'd love to give it another try. Who knows with a bit of practice I might be able to help a few other people too.
     
  11. Nigel

    Nigel pfm Member

    Can the inner lens be cleaned without having to remove the CDM9 pick up from the player?
     
  12. Mike P

    Mike P pfm Member

    Hi Nigel,

    No I'm afraid not and it's a nightmare of a job to be honest but worth trying before you go to the hassle of attempting to source a replacement laser.

    You need to remove the pick-up from the transport and then disassemble the pick-up itself which requires you to de-solder a few tiny (and very fiddly) solder joints.

    With CDM9 lasers no longer in production we need preserve the units that are left. Don't throw one out before checking if the inside lens needs cleaning. I can't guarantee it'll work but if you'd seen the amount of dirt inside mine you'd appreciate it's certainly worth a try.

    You can easily clean the outer lens though with the pick-up in-situ. Just remove the case/lid of the player and very very gently wipe the lens with a cotton bud tip dipped in isopropyl alcohol or window cleaning fluid.
     
  13. 337alant

    337alant Negatively Biased

  14. Nigel

    Nigel pfm Member

    Cheers Mike. Glad to say, mine is working fine. Reading your comments, I'll leave well alone.
     
  15. Mike P

    Mike P pfm Member

    Hi Alan,

    I've already ordered a refurbished pick-up from China via ebay (different seller though). Fingers crossed it's OK! I probably won't know for a few weeks as I expect it to take a while to arrive. I checked the sellers feedback profile and he has positive feedback from other buyers of these pick-ups.

    As I understand it some cheap soldering irons can leak some DC/static. To me it reads like he is suggesting that you turn off the iron just prior to performing the soldering operations. Is that how you interpret it?

    I always use an antistatic grounded wrist loop when handling lasers and on the CDM9 pick up I follow the service manual advice of putting a paper-clip across the terminals of the flexble pcb/ribbon connector.
     
  16. 337alant

    337alant Negatively Biased

    Mike yes thats what I thought he was trying to say as well, intrested to know if it works ok when you get it :)

    Alan
     
  17. Mike P

    Mike P pfm Member

    In the end I took a gamble and purchased one of the 'reconditioned' CDM9 laser heads available on ebay. These tend to be advertised by sellers based in China and Hong Kong so I was a bit sceptical about the quality.

    Anyway it arrived yesterday and I just finished fitting it about an hour ago......

    AND IT WORKS!!

    I'm a very happy bunny indeed. For anyone else in a similar position the ebay seller I used is zhzy5500.
     
  18. jonnoshore

    jonnoshore physicist, engineer and healer

    Is this what stops Naim CD3's from working?

    I have a CD3 which stopped working and I have my AAA5 in it's place.

    John
     
  19. MJS

    MJS Technical Tinkerer

    It's the same fault with CD3's, yes. And as often as not just the disc turntable getting pushed down the motor shaft.
     

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