CD50 Issues -

iagreewithjosh

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iagreewithjosh Posted: Sat, Nov 24 2018 10:49 PM

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Hi All,

I have a CD50 which up until last week was working fine. It has since developed a number of issues, none of which I can seem to figure out. I assume it was a lack of maintenance from the previous owner. I've only had it a month.

Every CD I have tried starts from the beginning of the 1st track every time, so I don't think it is the disk drive motor....

The issues are:

It has a lot of trouble finding the tracks when I press skip. Sometimes taking up to 10 seconds. This seems to be worse when the laser chassis is closer to the outer edge of the disk (later tracks).
It gets stuck and glitches at random parts of songs which it was able to play last week no worries. If I play the same CD again it may or may not happen. Most likely it will happen at a different track.
The laser chassis does not return to home after finishing a CD, so the next time I press play after being in stand-by mode the laser has to return and the CD will eject itself before it gets back to the starting position. When this happens the play button becomes unresponsive and I have to press the disk tray to close. The play button then works and the laser moves home and the disk starts.
If I skip from the last track back to track 1, the laser moves (slowly) back to home but it can't find the start of the track. Usually starting 1 minute into the 1st track.
The disk drive motor seems a little louder than it did when it was working fine. And for some disks it seems to squeak... I don't know if this was the case previously because I didn't play this disk when it was working properly.

If anyone can shed any light on this that would be greatly appreciated.
I assume it just needs some adjustments made to the radial bias and focus circuitry. But I don't have a test disk or easy access to a signal generator or oscilloscope. If need be I can probably get a hold of SG or Osc, but would rather not have to.

Cheers,
Luke

iagreewithjosh

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iagreewithjosh replied on Tue, Dec 11 2018 7:43 AM

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So I've managed to get it working quite well.

The returning from last track to the first seems to work every time without fail.
Selecting tracks happens within seconds, still a little slow at out edge of the disk.
Still sometimes gets stuck at outer edges and glitches. I think this is due to a combination of focal bias being incorrectly adjusted, and warps in the CD. The lens has to move much farther at the outer edges as the warps are more prominent there.

But it still has issues when playing after the disk has finished. After pressing play the laser carriage starts to return home and before it gets all the way back, the disk ejects and the play button becomes unresponsive.
The carriage gets nearly all the way back, literally within a few mm before the disk ejects.

Does anyone know what might be causing this? It's the only issue that's annoying me now as the others only happen on disks with more than 20 tracks, which I have very few.

tournedos

Finland

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tournedos replied on Tue, Dec 11 2018 3:36 PM

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iagreewithjosh:
But it still has issues when playing after the disk has finished. After pressing play the laser carriage starts to return home and before it gets all the way back, the disk ejects and the play button becomes unresponsive.
The carriage gets nearly all the way back, literally within a few mm before the disk ejects.

I have a vague feeling that this is normal (or at least common) and caused because many CDs are actually longer than the standard allows. The system times out before the carriage has reached the other edge.

I sold my CD50 years ago, but I seem to recall it did just that.

--mika

Dillen

Copenhagen / Denmark

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Dillen replied on Tue, Dec 11 2018 9:39 PM

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A Beogram CD50 is not just a Beogram CD50.
There are so many differences, production changes, aftermarket modifications etc.
Some machines had some modificaations, others have other, depending on which batch it was originally, which modifications
was made from factory, what owner(s) later complained about and what restorers like you found.
Hardly two machines are completely identical by now.

The first production batches of CD50 did exactly as you describe, after playing a fairly long CD.
A modification will correct it - in some of them...
In others it will have no effect.

It's not really a fault with the deck, - it's just one of its lovely quirks.

Martin

iagreewithjosh

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iagreewithjosh replied on Tue, Dec 11 2018 10:14 PM

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Thanks for your replies Mika and Martin. That is definitely an odd quirk.

Is there anyway to find if the modification would work on my CD50?
And if so, what is required for the modification? I wouldn't mind trying it out if anyone knows how to do it.

Cheers,
Luke

Dillen

Copenhagen / Denmark

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Dillen replied on Tue, Dec 11 2018 11:07 PM

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iagreewithjosh:

Thanks for your replies Mika and Martin. That is definitely an odd quirk.

Is there anyway to find if the modification would work on my CD50?
And if so, what is required for the modification? I wouldn't mind trying it out if anyone knows how to do it.

Cheers,
Luke

I will have to look it up, but if I remember correctly, the modification is a matter of fitting a capacitor - depending on the production block number.
The number is a one-digit hexadecimal number (0-F) and it is found, either stamped or handwritten, on the label at the right side of the internal vertical metal plate (divider).

Martin