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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022

 

Beogram CD-50 Goes crazy after 2 minutes

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Nick
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Nick Posted: Mon, Feb 1 2021 5:28 AM

I just finished replacing the belts on the CD-50 and fixing a couple mechanical issues, and everything works perfectly for a short time.  Mechanically, the door and the drive work for reading a CD and playing it through RCA.  It seeks forward to the next track, and will pause and resume just fine.

After about 2-3 minutes of normal playback, however, the player starts jumping around, playing pieces of songs before jumping forward and trying to play another piece of a track, then jumping forward again and trying to play another piece of a track.  Audio comes through but it only plays for a few seconds before jumping forward again.

During this time, the red display seems to be confused, displaying the wrong information as the time jumps around wildly.

I unplug the unit (so it restarts rather than resuming) and it will play just fine for another 2-3 minutes.

Does anyone have experience dealing with this issue?  Any idea of what might be the problem?

As a side note I should mention that I poked around inside the unit, and WOW is this a first-generation player.  There are spliced wires and last-minute changes, caps soldered in random places, etc.  It's truly quite a mess inside.  I have a backup unit for parts and it's identical.  I'm really surprised at how messy the boards ended up on it.

solderon29
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There were a lot of aftermarket "tweaks" to this machine,but they were proper factory or Service Agent jobs,so should be quite presentable.

If your machine is a mess inside,it suggests that the "phantom bodger"has paid a visit,and probably been generally poking around in there,and messed up the electrical alignment>

These are good machines and robustly made.

Can you compare your two machines,and ascertain if anything is obviously different in the "messy" one,such as missing parts,wires in different places etc?

You may be able to get both machines functioning well?

Nick

Nick
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Nick replied on Fri, Feb 5 2021 6:51 PM

Thanks for the reply - the "mess" observation was just that there were a lot of cables and patch jobs.  The two actually match component for component, so I think it's supposed to be that way.  :)

The problem does persist, though, where it will play back perfectly for 2-5 minutes, then it will start skipping all over playing pieces of songs.  The counter on the display seems very...confused as well.

I saw on another forum to try cleaning the motor as it could be pulling too much voltage and causing problems, so I disassembled it and cleaned it, but the problem seems to persist.  Any suggestions would be helpful.  Thanks!

solderon29
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Does the machine perform normally when the top pcb is raised into it's service position?

If so,you should note that the wiring loom at the front of the board has a label on it advising that it's position is critical.

If it's not positioned as in the diagram,then noise can be picked up by the pre-amp,and cause all sorts of odd problems.

Nick

Nick
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Nick replied on Fri, Feb 12 2021 7:04 AM

I put it into the service position and the problem persisted, but when I reassembled the behavior of the problem changed.  Now, it skips backward after 2-4 minutes and returns to track 1, and doesn't require unplugging in order to reset and play properly.  Now, I merely have to use the power button to cycle the power.

Where is this loom/configuration diagram?  I have the service manual but don't see the label you mentioned. 

Nick
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Nick replied on Fri, Feb 12 2021 7:16 AM

Ok, you were 100% correct.  I separated a few wires and all of the behavior is now completely normal.  Do you have the full diagram you referred to?  I still want to see where everything is supposed to be.

solderon29
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solderon29 replied on Fri, Feb 12 2021 10:52 AM

Good new's!

The suspect cable is a five wire ribbon at the front edge of the pcb's,and it goes between P302 on the top board,to the corresponding P302 on the lower board.

It should have a label fixed to it showing how the cable should be placed.It needs to be wound up so that it is kept away from the first stage of the servo pre-amp IC101(CX20109,top board)when the board is lowered.

Its a bit fiddly,but I usually tie a small cable strap around it when it's bunched up.

Enjoy your CD50's,I've got four of them now,great sounding unit.

Nick

Nick
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Nick replied on Tue, Feb 16 2021 11:25 PM

There's no label of any kind but those instructions are very helpful.  I'm moving but will probably get back to this project in a few weeks.  I just completed repairs on my Beomaster5000 and MCP, so I'm thrilled that I can set all of this up in my new space.

Thanks again for your help, without the label or your direction I would never have found that problem.

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