Mission PCM7000 with poorly laser

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#21
Re: Mission PCM7000 Cd player

poynton said:

As can be seen, this is a standard Philips player modified by Mission with the addition of the extra audio board.
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guido said:
Yep,

Looks like it's based on the philips cd650. Instead of the additional filter board, it's the mission pcb. With connection to front, so i guess it has volume control (?).

Main pcb looks similar, even the i/v opamps are still there.
Click to expand...


As far as I remember, the main PCB was used in many versions of Philips/Marantz cd players of this time.

Certainly, it is almost identical to Philips CD160 and Marantz CD273 (both small format players).

The boards actually had provision for the extra boards and remote option but this was not always implemented.

I think the CD850 is different but may be wrong.

Andy
 
#27
Hi, Andy. Are you back in the UK yet?

I am interested in buying one of your laser assemblies from you as discussed a few weeks ago. Can you confirm if they are second hand and that they are tested as working before you post them out.

Also, I am not sure if I need the PCB on it or not as this may be Mission specific rather than generic to the assembly.

Looking forward to your reply so I can bring my player back to life very soon ;0)


Pete
 
#32
Hi Andy,
Got your CDM 2 replacement this morning - thank you. the black housing is completely different to mine, so I swapped the laser assembly, which is identical. Put it back together and loaded a disc and had no joy. The disc span up, but as before there was no servo noise indicating the disc was not being read and I then got "Disc Error" on the display. I took the drive out and started to fiddle with the pot on the back of the main PCB. If you consider the POT can be set between 10mins and 50mins (assuming a clock face), then the POT was set at about 25 mins originally. I messed around with this and eventually got the disc to read if the POT was set to about 12 mins (just a notch up from the counter clockwise home position). It takes a while for discs to read, and still sometimes I get a "Disc Error" warning, but discs are now playing fine. 🙂

Player still has a great warm sound, and an excellent depth of sound field, so it was a good £20 investment - thanks again.

Now I have got the laser sorted out, do you think I have another issue with the lack of sensitivity when reading discs surrounding the setting of this POT? If so, what would you suggest I look for? In an earlier post on this thread, another contributor (Quido?) said about a capacitor may be at fault.

"In many cases it's not the laser, but just a cheap cap that needs to be replaced (33uF cap). Suggest to try that and try to calibrate the transport. Worth an attempt."

What do you think? Do you think this is something I can make an improvement on, or should I just be grateful for getting my player to play discs again?

Pete
 
#34
Andy,
Put CD player on again today. From cold, player would not play tracks 1-5 on 5 different discs, but would play tracks 6 onwards. After a while (10-15 mins) and the player had 'warmed up', it would then play tracks 1-5. When trying to access one of the first tracks, you can hear the servo trying to locate the starting point, but it takes a lot longer than when accessing tracks 6 onwards. Is there a way of increasing the laser sensitivity? I reckon if the laser was more sensitive, then this should avoid the excessive delays trying to locate the start point of a track. What do you think?
 
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