micromega stage cdm 12.4 spare?

compact disc, dacs, mp3 players and streaming audio
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marelindo
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micromega stage cdm 12.4 spare?

Post by marelindo » 26 Oct 2019 19:04

Hi everybody and thanks in advance for any help.
I have the above cdp and I really like its sound. A couple of years ago replaced the transport which was skipping a bit to much by one I got from ebay and it sort of worked; the skipping was gone but sometimes it wouldn't recognize a cd (no disc) up to now when it rarely recognizes a disc.
Reading around the issue it looks like these transports from ebay or elsewhere around £15 mark are bad quality.

My question: does anyone knows where to source a good quality cdm 12.4?

Thanks
Marco

GuidoK
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Re: micromega stage cdm 12.4 spare?

Post by GuidoK » 26 Oct 2019 20:17

Isn't it just a matter of replacing the laser module?
(Maybe you can get away with turning up the gain for a few years)

marelindo
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Re: micromega stage cdm 12.4 spare?

Post by marelindo » 27 Oct 2019 10:25

Turning up the gain; how do I do that?
Replacing the laser module; does this means I can find a quality one? Replacing the transport was something fairly easy to do, not so sure about the laser.
Thanks

GuidoK
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Re: micromega stage cdm 12.4 spare?

Post by GuidoK » 28 Oct 2019 01:00

marelindo wrote:
27 Oct 2019 10:25
Turning up the gain; how do I do that?
Normally one of the trimmer pots inside is the gain for the laser diode. I don't know which one as I dont have a micromega stage nor the service manual.
Usually a cd player starts acting up as the output of the laser diode gets less and less. Turning up the gain of the diode gives it a little bit more output
Replacing the laser module; does this means I can find a quality one? Replacing the transport was something fairly easy to do, not so sure about the laser.
Thanks
I don't know about the quality, but ebay is littered with them.
You can get just the laser module, but it's probably easier to get the complete pickup/motor plate:
https://www.ebay.com/itm/Philips-CDM12- ... 3598931475
https://www.ebay.com/itm/Philips-CDM12- ... 3366894851

Or are these the ones that are proven bad quality?


I dont know how long ago you replaced your module, or how many hours it has run since, but I wouldnt rule out that the trimpots on your pcb need recalibration. But for that you need the service manual (and electronics knowledge, some equipment etc)

ravelax
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Re: micromega stage cdm 12.4 spare?

Post by ravelax » 28 Oct 2019 19:28

From what I've read, adjusting the laser power will only hasten the demise of the laser and is therefore not advisable, unless you know what you're doing and have the proper test equipment. Skipping can be due to all sorts of problems, more probably due to a dirty lens or a worn spindle motor. A very in-depth guide can be found here: https://www.repairfaq.org/sam/cdfaq.htm

marelindo
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Re: micromega stage cdm 12.4 spare?

Post by marelindo » 28 Oct 2019 23:12

Bingo! Turned the pot a tiny bit, no change. Turned it another bit, it reads every cd I tried so far and jumps from first to last track and back again with no issue at all. I have not had time to do some extensive listening but it looks sorted. Excellent! Is there any issue with this gain increase?
Thank you very much for your help. Cheers

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