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Philips CD160 not working

Discussion in 'd.i.y.' started by a.palfreyman, Jul 31, 2017.

  1. Mike P

    Mike P pfm Member

    Hmm...the first thing I would do is to replace any electrolytic caps in the servo section. Where are you up to with the recap?
     
  2. a.palfreyman

    a.palfreyman pfm Member

    Mike,
    Replaced all caps on servo board except the main pair of 220uf and it has probably had 20-30 hours use since replacing these prior to this problem arising. Also replaced all axials on mother board but not replaced any others yet. Maybe I should just do it as I really like the sound!
    Ta,
    AP
     
  3. Dowser

    Dowser Learning to bodge again..

    Assuming you are going to keep it, I would replace all the electrolytics - they are very old now, and best to simply replace them once and then know any future problems are not related to them. I assume it is either a cap or a dry joint/bad connection somewhere, and that it fixes itself as the player warms up (you can test by leaving it powered on overnight).

    But given it is causing skipping, maybe start with the 2x 220uFs if you want to get all scientific with it :)

    Richard
     
  4. Mike P

    Mike P pfm Member

    I completely agree with Richard (as usual). Replace the electrolytics and then you can at least rule them out as the cause. They should be changed anyway due to their age so you won't be wasting your efforts.

    While you have it apart inspect it carefully for dry solder joints. You'll tend to find them around anything that gets mechanical stress e.g. connectors and anything that gets hot, such as voltage regs and rectifiers.

    Double check that all connectors are fully home too.
     
  5. a.palfreyman

    a.palfreyman pfm Member

    Good points again thanks chaps. I have already done all of the sockets where they are soldered to the boards as well as the regs so it is likely to be electros going over. I'll get this sorted and go from there. Any good sources for the 6800uf 25V main electro (which uses the outer can a -ve) as this is quite small for the capacity?
    AP
     
  6. Mike P

    Mike P pfm Member

    I get most of my parts from Farnell, the parametric search tool is incredibly useful. The downside to ordering from Farnell is a high(ish) min carriage paid order size of £25.

    RS Online can work out cheaper for small orders (hint: find what you want on Farnell first then search for it on RS using the part number to see if they have it).

    If Farnell don't have anything then Mouser or Digikey will probably have what you need.
     
  7. Dowser

    Dowser Learning to bodge again..

    Me also Farnell or Mouser for caps, with Farnell having better prices if order value is CHF 50 plus so you get free shipping - RS too expensive here in CH.
     
  8. a.palfreyman

    a.palfreyman pfm Member

    Don't use Farnell because of the reason you both state i.e. order size.
    Replaced the 220uf servo board caps with 470uf ones I had to hand and that has improved things somewhat but I am now going to replace the remainder. Is there a preference for the two 100uf caps in the signal path? Rest I will just replace with generic (nothing special) caps. So long as I don't use ultra-low ESR ones on the regs, all should be OK methinks. Can't find anything of 6800uf with an earthed can though.
    TIA,
    AP
     
  9. Dowser

    Dowser Learning to bodge again..

    You mean the 100uF output caps? They're bipolars in their from memory. Argh - I should have thought - I have 100uF wet tants here and I could have popped a couple on the bag with the display when I sent it...sorry!

    I have also used 10uF Wima's here, as well as 2.2uF boutiquey audio grade caps. I preferred the wet tants to both.

    For the 6k8uF - as long as you can fit it with a positive and a negative, any thing should work fine, no?
     
  10. a.palfreyman

    a.palfreyman pfm Member

    No probs. Have bought some Nichicon fine gold caps to try. Wasn't sure if they used a canister type for the 6800uf for shielding, but as I couldn't find anything (except for NOS in large quantities from USA), just bought a standard electro for the job. Hopefully get these and the new display in at the w/end.
    Ta,
    AP
     
  11. Mike P

    Mike P pfm Member

    To replace the 100uF output coupling/DC blocking caps film caps are the usual recomended choice. Some boxed radial Wima Mks with 5mm pitch will drop straight in without any messing about and will be an upgrade over an electrolytic. Anything over a few uF will usuall be fine. I use a pair of 4.7uF Wima caps in one of my CD players and they sound just fine.

    Richard really likes wet Tants which are something I've not tried myself. I'll have to give them a try sometime.

    Big boutique caps on long flying leads are not a good idea as they can just act like a big antenna for picking up noise.

    My personal favourites are some compact Panasonic MKP caps or some new old stock vintage RS branded radial MKC (polycarbonate).

    If you want to use electrolytics then I really like Elna Silmic for signal path coupling duties.
     
  12. a.palfreyman

    a.palfreyman pfm Member

    Mike,
    Thanks for that. I decided to go for the fine gold as they have a good rep and was a bit concerned that something much smaller (poly film) would sound rolled-off with 4k7 loading on the output side of these caps. To be honest the old ones in there don't actually sound too bad.
    Richard,
    Received and fitted the display last night. :) Does the trick nicely thanks. :cool:
    Got some caps ordered for fitting at the w/end.
    Thanks guys,
    AP
     
  13. Dowser

    Dowser Learning to bodge again..

    Cool, thanks for the update - you had more success than me yesterday then :)
     
  14. a.palfreyman

    a.palfreyman pfm Member

    Finished recap (except for 1.5uf bipolar on servo board) and during the first run it occasionally skipped forwards for about 10 mins and then settled. Two further sessions of a few hours and all seems to have settled down. The 1.5uf bipolar appears to be a coupling capacitor from the laser so not sure what it does or how critical it is. What are the benefits of using a dedicated +5V supply to the SAA7220? I have a couple of ALWSR's somewhere that are configured for +5V so I could lift the feed resistor to the SAA7220 and use an ALWSR fed by the raw 11V supply line. Thoughts anyone?
    AP
     
  15. Mike P

    Mike P pfm Member

    The SAA7220 is a very noisy and power hungry chip and giving it a dedicated power supply can bring enormous rewards.

    In my old Arcam Alpha 5 project I gave the SAA7220 its own dedicated PSU using a 7VA toroid transformer followed by rectifier diodes, a 3300uF smoothing cap and an LM317 reg. It was probably the single most rewarding mod I did to that player.
     
  16. Mike P

    Mike P pfm Member

    This is the little kit I used. They are dirt cheap and great for this sort of thing:

    http://www.ebay.co.uk/itm/LM317-lin...823704?hash=item4ad4fb5f98:g:62kAAMXQYwFRiL59

    I tweaked it by replacing the diodes with Schottky 11DQ10 types, beefed up the smoothing cap to a 3300uF quality Rubycon ZLH and then used a pair of red LED's to set the voltage in place of a resistor. I also removed the small 0.1uF film cap on the output as I think it could cause ringing from the reg.

    The other aspect you should look at carefully is the power supply decoupling cap at the SAA7220. An Oscon does very well here (I used 47uF).
     
  17. a.palfreyman

    a.palfreyman pfm Member

    Mike,
    I see what you mean about the SAA7220 being noisy. I (unfortunately) didn't measure it before removing the resistor and powering with an ALWSR but 'scoped after fitting and it certainly generates a lot of crap (30mV p-p at about 20Mhz). I know it's not the ALWSR oscillating (despite having the original 22nF cap but with the original 47uF replaced with a 220uF across the supply rails) as the noise is worst at the chip and of a lower amplitude at the ALWSR output, and I have about 125-150mm of wire between ALWSR and circuit board. This seems to have increased clarity (I found I could tweek the treble up slightly). I have also just put gyrators in to power the opamps as I noted a lot of voltage swing (circa 120mV p-p) across the 100R resistors feeding the opamp supplies. Had to trouble-shoot after fitting a transistor back to front, which then blew but got that sorted so will get the chance to listen tonite.
    Thanks,
    Andy P
     
  18. a.palfreyman

    a.palfreyman pfm Member

    Well, after sorting the gyrators to the opamps (4 off - one for each neg and pos supply) I wondered where all the bass had gone! However, this seemed to settle down over a few hours (I had two three-hour sessions); there is an increase in clarity and the bass has now settled (yes, I do believe in burn-in, especially on capacitors). I wonder if the large supply ripple was causing problems with modulation to the opamps (LM833)? The increase in clarity also perversely came with a perceived loss in the upper mids, so I have also adjusted the roll-off on the mids (moving it upwards) as I had had to split the crossover frequencies to get rid of some unnatural "whistle" on human voices. Looks like I will also have to troubleshoot a second CD160 I just bought (so I can compare modded to unmodded) as I suspect this second player was damaged during delivery - it was working when sent but now won't read a disc and there is a broken mounting lug on the front panel. The disc spins and you can hear the laser "clicking" as it moves up / down but all you get is "Err". Will re-read Richards CDI thread for inspiration. Is there and English version of the service manual? I have the German one unfortunately.
    AP
     
  19. a.palfreyman

    a.palfreyman pfm Member

    Got the service manual for the CDM2 and checked the laser on CD160#2 and that is working OK so replaced the 'lytics on the servo board and all is working:) Will recap the whole machine at the weekend.
    AP
     
  20. Big John

    Big John pfm Member

    I wondered if my
     

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