Hi Folks. I have a Mission PCM 7000 that I bought new in the 80s. It's been used very infrequently as I've ripped most of my CDs or buy digital downloads and stream the files to a DAC. But when I did try to use it recently, first the disc went in awkwardly and jammed the tray (maybe the CD wasn't in the tray properly), but the tray did open (pressing eject) and all that seems OK now. BUT every disc I try spins for a few seconds then stops, with the Disc and Error lights on in the panel. I took the lid off, and everything looks OK (mechanicals seem to work properly, no bulging capacitors on the boards). I also darkened the room to see if I could see any laser light when I loaded the disc, and saw nothing - but don't know exactly where to look or whether I should be able to see anything. Any advice to get this baby diagnosed or working would be much appreciated.
Busted laser?
See supply. Repair or replace, good luck with laser.
Find out OEM and model, most used Japanese or Philips mechanisms.
There was a member here, 'Electricboyo', I think, who knew most CD units very well. Last seen January, when I checked.
Search for him.
See supply. Repair or replace, good luck with laser.
Find out OEM and model, most used Japanese or Philips mechanisms.
There was a member here, 'Electricboyo', I think, who knew most CD units very well. Last seen January, when I checked.
Search for him.
Thank you. I'll search for Electricboyo. In the meantime, I'm trying to figure out how I can ascertain whether the laser is working. It looks like I may not be able to see it because its beam is apparently in the 740nm near infrared range. Since I have a newer iPhone that uses LIDAR (also infrared), I'm trying to figure out whether said laser would show up (if working) in a low light iPhone photo.
Lift the disc clamp up without a disc inserted before it tries to read TOC, look at laser slightly off axis and you should see it bob up and down, and see a red emission from laser (at same disc motor should kick a couple of times). Any of these things not happening is a clue where to start - good luck!
Thank you! I had to remove the clamp with spring to see it, and there is a bob, and I could see the tiny orange light. The mechanism that swings in the curved slot that holds the laser stays put at the inner end of the slot, and didn't try to traverse the slot at all, which may be correct (I don't know). Although I've had no luck finding a Philips CD650 service manual with the diagnostic steps in English, I did notice some things in other Philips service manuals discussing a service mode where you'd hold down some of the front panel buttons as you plug in the power cord. In that mode you can apparently test some things, including whether the laser holding mechanism will traverse back and forth in the slot when the forward and reverse front panel buttons are pressed. I might give that a try, but don't know whether it's even applicable to the PCM 7000, or whether it would even be useful given my issue. I also saw some posts about a 33uF capacitor on the servo board that had a history of going bad, but because that appears to relate to an earlier version of the board (mine is CDM 2-03011) I don't believe that such a capacitor resides on the servo board in my player. If you have any further advice, I'd sure appreciate it!!
I think a good working clock signal is required for the motor to start spinning (from memory..., to be confirmed).
You are right about the service menu steps... enter the service menu and then move the sled front <-> back (from the front panel buttons) to confirm all is good.
I have a great CD650 service manual copy... 20MB. Send me PM.
EDIT: holy cr*p... the service manual also contains a full, comprehensive CDM1 mechanism service manual... sweet!
You are right about the service menu steps... enter the service menu and then move the sled front <-> back (from the front panel buttons) to confirm all is good.
I have a great CD650 service manual copy... 20MB. Send me PM.
EDIT: holy cr*p... the service manual also contains a full, comprehensive CDM1 mechanism service manual... sweet!
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I've split the manual into 2... here's the CDM 1 part
(Unfortunately, the CDM960 part is still 17MB... can upload it here - too large a file...)
(Unfortunately, the CDM960 part is still 17MB... can upload it here - too large a file...)
Thank you! The CDM part looks great! I will PM you re the remainder. Buy the way, my motor does spin, but when I put in a disc it spins for 2-3 seconds and then stops while the display then lights up the Disc and Error elements.
Too add to the Google Drive suggestion, I can't seem to do a PM. Possibly because I'm relatively new and still on probation so to speak. Of course it could be because I don't know what I'm doing (I went to Conversations and there's nothing - including no button to start one).
I'd be looking at the RF test point to see if, when the disk spins, I can see the eye pattern...
Thanks, Extreme_Boky -- this will be great!
Sounds a little more like Focus Failure to my wine-addled mind. 😉
Not in the direct logical flow of the thread, but 'sudden death' of a solid state Laser this old and only slightly used, would be unusual. They're much more likely to very slowly fade emissions.
Cheers
Sounds a little more like Focus Failure to my wine-addled mind. 😉
Not in the direct logical flow of the thread, but 'sudden death' of a solid state Laser this old and only slightly used, would be unusual. They're much more likely to very slowly fade emissions.
Cheers
Extreme_Boky: Thank you for the manuals! Since the player manual is for the CD960 (instead of CD650), I assume it is still applicable.
Rick PA Stadel: Focus failure would make sense, given that the laser is working. I'll try to figure out where the test points are (I do have a scope, but am a scope novice). I also wondered whether an adjustment of the potentiometer that controls power to the laser might do something useful.
Rick PA Stadel: Focus failure would make sense, given that the laser is working. I'll try to figure out where the test points are (I do have a scope, but am a scope novice). I also wondered whether an adjustment of the potentiometer that controls power to the laser might do something useful.
Use a marker pen to mark the pot positions, take a photo as well.
Clean the lens, adjust pots till you get improvement.
Check the service manual and actual figures for laser voltage and current.
Might be useful.
Clean the lens, adjust pots till you get improvement.
Check the service manual and actual figures for laser voltage and current.
Might be useful.
Don't touch the pots unless you have a laser power tester, it won't end well.
How about checking the power levels, V and mA, with a digital meter?
My mechanic friend does this - set the pots - all the time, but he is experienced.
Not really for new persons, so I did say take a photo.
My mechanic friend does this - set the pots - all the time, but he is experienced.
Not really for new persons, so I did say take a photo.
A good task for that 'scope that you admit needing practice with, would be to confirm the quality of all power supplies. For gear of that vintage, especially 'lightly used', a failed / failing electrolytic capacitor is uncomfortably likely.
Regards
Regards
Thanks to all of you! I think it's time that I stop fretting about it and get down to doing something. Re the scope, I did use it (a fairly inexpensive pre-owned Hantek unit) to successfully do a trace and find a bad cap in an old Cyrus 2 amp I had, but the service manual for that was a novice's dream. I'm hoping that one of the schematics in the CDM manual will at least match my servo board since nobody seems to have a service manual specifically for the Mission PCM 7000 player itself. Thanks again!