Hello Audio Experts!
A couple of years ago I took a chance on a used cdp, the rare & highly acclaimed Berendsen CDP1. It even has an upgraded cap or three. Really, really, sounds great!
But now it is having trouble reading CDs, mostly my CD-Rs but also with store-bought CDs sometimes. It most always will take lots of time to recognize a disc. It is getting worse....
So from my readings it looks like the laser pickup might be weak. I opened the machine & greased it up & adjusted the laser power. No better. So I assume it is time to replace the laser. I think I found the right pickup, & this looks to be a fairly easy thing to do providing there are no tricks which I don't know about.
Am I barking up the right tree? Is this as easy as throwing a bone to a dog?
TIA! Murf
PS: So like I opened my cdp, and to see what was happening better I took off the plastic crossmember that goes across the transport tray & holds the magnet disc which would sit atop the cd & mates with the drive spindle when playing . With this removed, all CDs play, even CD-Rs! If I put it back on, even without tightening the screws down, no play.
Um, ideas, please?!?!
pls...pls...pls....
A couple of years ago I took a chance on a used cdp, the rare & highly acclaimed Berendsen CDP1. It even has an upgraded cap or three. Really, really, sounds great!
But now it is having trouble reading CDs, mostly my CD-Rs but also with store-bought CDs sometimes. It most always will take lots of time to recognize a disc. It is getting worse....
So from my readings it looks like the laser pickup might be weak. I opened the machine & greased it up & adjusted the laser power. No better. So I assume it is time to replace the laser. I think I found the right pickup, & this looks to be a fairly easy thing to do providing there are no tricks which I don't know about.
Am I barking up the right tree? Is this as easy as throwing a bone to a dog?
TIA! Murf
PS: So like I opened my cdp, and to see what was happening better I took off the plastic crossmember that goes across the transport tray & holds the magnet disc which would sit atop the cd & mates with the drive spindle when playing . With this removed, all CDs play, even CD-Rs! If I put it back on, even without tightening the screws down, no play.
Um, ideas, please?!?!
pls...pls...pls....
The machine changed it's mind...
Now the cd tray won't stay closed with the top magnet off of the spindle. The machine with the magnet on is now reading only redbook, no cdr's at all.
Murf
Now the cd tray won't stay closed with the top magnet off of the spindle. The machine with the magnet on is now reading only redbook, no cdr's at all.
Murf
Hi Mooly,
The machine is pretty much the same as a GamuT, if that helps. DAC is a Crystal cs4290, laser pickup is an 'OPC-A15', I can't find any ID for the transport, on the web but it has #s GM9350, & what I figure to be the control board has Samsung chips, but no adjustment pots.
Thanks, Murf
The machine is pretty much the same as a GamuT, if that helps. DAC is a Crystal cs4290, laser pickup is an 'OPC-A15', I can't find any ID for the transport, on the web but it has #s GM9350, & what I figure to be the control board has Samsung chips, but no adjustment pots.
Thanks, Murf
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Boy, I sure don't see $2000 retail in that chassis!
Looks like a Sony loading mech, but pickup # doesn't coincide. A photo with tray open & clamping support removed would help. From description, sounds like it's possible, assuming not a weirdly bad platter motor, that the probable cause is that a "press-fit" platter has slipped on the motor shaft, giving wrong focus distance. Generally, if you roll the laser to innermost position, the bottom edge of platter is usually about 1mm or so above the top of the laser plastic cover, so that cd surface is 2-3mm above lens. Just ballpark figures there, but an easy check to make.
Looks like a Sony loading mech, but pickup # doesn't coincide. A photo with tray open & clamping support removed would help. From description, sounds like it's possible, assuming not a weirdly bad platter motor, that the probable cause is that a "press-fit" platter has slipped on the motor shaft, giving wrong focus distance. Generally, if you roll the laser to innermost position, the bottom edge of platter is usually about 1mm or so above the top of the laser plastic cover, so that cd surface is 2-3mm above lens. Just ballpark figures there, but an easy check to make.
Not at all sure, but I would guess that it is a Samsung laser(seems supported by presence of Samsung chips), very much in imitation of a Sony KSS213 type laser(though unlikely a drop-in replacement) and it's mech. The loader is a dead ringer for a Sony mech, if it's not the real thing. However, I can't at the moment think of another likely cause for the symptoms you are experiencing.
I can't come up with much either I'm afraid.
A scope check of the RF signal is really what is required as it reveals so much.
Could it be a weak spindle motor ? as it played without the weight of the clamp (if thats what you mean). A trick that sometimes works if only to prove something is to apply a 9 volts battery across the motor for a few seconds to "burn" and clean off dirt on the commutator. If you try that you must isolate the motor electrically first.
A scope check of the RF signal is really what is required as it reveals so much.
Could it be a weak spindle motor ? as it played without the weight of the clamp (if thats what you mean). A trick that sometimes works if only to prove something is to apply a 9 volts battery across the motor for a few seconds to "burn" and clean off dirt on the commutator. If you try that you must isolate the motor electrically first.
It seems my laser does work. BUT, it is not reading CD-Rs, and it looks like the previous owner had adjusted the laser power up. The control board (?) has no adjustment pots, so I figure this stuff is working well. The laser pickup goes in & out, up & down.
Murf
Murf
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I think all you can do is try another pickup but without detailed scope checks it is a guess in the dark.
CDR's vary enormously in how "good" the recovered signal is and are dependant on discs and the CDR burner used... again the scope confirms what is actually happening.
You need to ID the pickup too.
CDR's vary enormously in how "good" the recovered signal is and are dependant on discs and the CDR burner used... again the scope confirms what is actually happening.
You need to ID the pickup too.
I dropped in a KSM-213 laser last night, & it went up down in out, but didn't recognize the disc, & didn't spin it.
Murf
Murf
Do the pickups come with a shorting solder blob on the laser PCB that needs removing ? Many pickups do for static protection.
laser pickup...
laser pickup is an 'OPC-A15'. Cost ~ $25.
A number on the metal plate which holds the pickup & motors is GM9350.
Murf
laser pickup is an 'OPC-A15'. Cost ~ $25.
A number on the metal plate which holds the pickup & motors is GM9350.
Murf
Thanks Mooly, I see the jumper is there.
I'm gone, but will be back after the long weekend.
Enjoy folks, Murf
I'm gone, but will be back after the long weekend.
Enjoy folks, Murf
Hello Audio Experts!
I put in a KSM213 laser, which is just a drop-in. After removing the solder "safety", it worked as well as the original laser, ie: it will play redbook cds but not cdrs. Thus, problem isn't the laser, so I'm pretty much stumped. The control board for the laser has no adjustments.
Thanks Folks, Murf :-(
I put in a KSM213 laser, which is just a drop-in. After removing the solder "safety", it worked as well as the original laser, ie: it will play redbook cds but not cdrs. Thus, problem isn't the laser, so I'm pretty much stumped. The control board for the laser has no adjustments.
Thanks Folks, Murf :-(
That's good that you have it working.
Maybe the CDR's aren't to standard... have you tried some burned on a different PC.
In the past for interest I have looked at the signal off CDR's I have burnt on the 'scope and find that they are not as defined as "pressed" or red book cd's. They all play OK but the point is they are not too red book standard in many ways. Also I find that (contrary to what you read) that the best results are obtained burning at the fastest speed.
I would try a new CDR burned on another PC first.
Could your existing CDR's have deteriorated... many report this although it is something I haven't experienced.
It really needs a scope now to look at the actual signals coming off the disc to check the quality is good and the amplitude is correct. I take it you didn't alter the setting of the pot on the laser before the solder link was removed. This adjustment should never be altered as its factory set.
Maybe the CDR's aren't to standard... have you tried some burned on a different PC.
In the past for interest I have looked at the signal off CDR's I have burnt on the 'scope and find that they are not as defined as "pressed" or red book cd's. They all play OK but the point is they are not too red book standard in many ways. Also I find that (contrary to what you read) that the best results are obtained burning at the fastest speed.
I would try a new CDR burned on another PC first.
Could your existing CDR's have deteriorated... many report this although it is something I haven't experienced.
It really needs a scope now to look at the actual signals coming off the disc to check the quality is good and the amplitude is correct. I take it you didn't alter the setting of the pot on the laser before the solder link was removed. This adjustment should never be altered as its factory set.
Hi Mooly
All my CDRs work immediately in my other player (berendsen cdp2) and in my car HK player. Many of the discs are newly made, and I have tried 4 different brands. All do the same thing with my players, so I don't figure that to be the problem.
Correct, with the replacement laser I kept the setting at stock. With the original laser it looks like the previous owner upped the laser power.
Thanks, Murf
All my CDRs work immediately in my other player (berendsen cdp2) and in my car HK player. Many of the discs are newly made, and I have tried 4 different brands. All do the same thing with my players, so I don't figure that to be the problem.
Correct, with the replacement laser I kept the setting at stock. With the original laser it looks like the previous owner upped the laser power.
Thanks, Murf
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Hi Mooly
All my CDRs work immediately in my other player (berendsen cdp2) and in my car HK player. Many of the discs are newly made, and I have tried 4 different brands. All do the same thing with my players, so I don't figure that to be the problem. Oh yeah, and they all worked fine at our Mem. Day rental house (Yamaha cdp).
Thanks, Murf
All my CDRs work immediately in my other player (berendsen cdp2) and in my car HK player. Many of the discs are newly made, and I have tried 4 different brands. All do the same thing with my players, so I don't figure that to be the problem. Oh yeah, and they all worked fine at our Mem. Day rental house (Yamaha cdp).
Thanks, Murf
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Difficult to suggest anything without actually putting a scope on this and seeing whats happening.
I know this sounds really odd but the fact that all the CDR's are OK in other machines doesn't mean there still isn't a problem with them... thats because the signal on CDR is nowhere near as well defined as a pressed disc and can fall outside of what some players recognise. Thats why I said to try discs burned on another PC.
In the first post you mention that red book cd's sometimes don't play at first! Now that of course is a fault. Did the replacement laser correct that problem with the red book discs ?
When a disc isn't recognised does the disc (cd or cdr) actually spin up to speed when you put it in or not. In other words does it spin and appear not to be recognised or, just not spin at all ?
Spindle motors (assuming a small DC motor) are another common trouble area generally.
Was it just the pickup you replaced or the whole chassis including the motors ?
I know this sounds really odd but the fact that all the CDR's are OK in other machines doesn't mean there still isn't a problem with them... thats because the signal on CDR is nowhere near as well defined as a pressed disc and can fall outside of what some players recognise. Thats why I said to try discs burned on another PC.
In the first post you mention that red book cd's sometimes don't play at first! Now that of course is a fault. Did the replacement laser correct that problem with the red book discs ?
When a disc isn't recognised does the disc (cd or cdr) actually spin up to speed when you put it in or not. In other words does it spin and appear not to be recognised or, just not spin at all ?
Spindle motors (assuming a small DC motor) are another common trouble area generally.
Was it just the pickup you replaced or the whole chassis including the motors ?
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