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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Sansui cd-x711 cd-player several problems!
Hi!
I have a sansui cd-x711 cd-player from the late 80's that have several problems. When a disc is loaded the lens from the pickup goes up and down a couple of times before reporting "no disc". After consulting another owner the startup sequence is supposed to be: drawer closes, and spindle/motor engages the disc, the disc starts to spin, the laser head tries to focus, then the disc starts to play. In my case the disc never starts to spin, the optical pickup that is of the linear tracking type (coils and magnets), whatever starting position is, doesnt move to the center. Both the motor and the coils are connected to a "RF/SERVO(f) board. What could the problem possibly be? Would be nice to get it going, it is a very nice unit. Dual power supplies, optical and coaxial outputs, balanced xlr outputs, and should have a very nice sound too. All help appreciated, /Erik |
#2
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I forgot to mention that I checked all leads to pickup and motor, they
are ok. However, there is no voltage at the terminal the motor connects to, probably the same thing for the coils at the trackingdevice connection. When it tries to focus, I can see a dim red light, apparently the laser is ok. There are a couple of boards in the unit, but in this case I think a part of the RF/SERVO(f) board is likely to be failing, the board is in two parts, the part where both the motor and tracking connects to is a vertical mounted little board on the larger mainboard, where the other cables from the pickup goes to. Hope you can help me on this one. Thanks in advance, Erik |
#3
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Your friend is wrong. It must focus FIRST, then spin the disc. Focus fails,
no spin. Quite possibly a bad laser pickup. At the moment it "should" spin, try helping the disc spin by giving it a push. May take a couple tries. If it takes off, even spinning weakly, the spindle motor is bad. Sometimes they can be fixed by spraying the brushes with cleaner. Let us know and if this is the case maybe we can walk you through it. Mark Z. "Erik" wrote in message om... I forgot to mention that I checked all leads to pickup and motor, they are ok. However, there is no voltage at the terminal the motor connects to, probably the same thing for the coils at the trackingdevice connection. When it tries to focus, I can see a dim red light, apparently the laser is ok. There are a couple of boards in the unit, but in this case I think a part of the RF/SERVO(f) board is likely to be failing, the board is in two parts, the part where both the motor and tracking connects to is a vertical mounted little board on the larger mainboard, where the other cables from the pickup goes to. Hope you can help me on this one. Thanks in advance, Erik |
#4
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Most systems will spin the disc then focus (this certainly applies to all
Philips units - in fact I've never seen a system that does otherwise). Usually the startup sequence is something like this: * Home the OPU (to the inside of the disc) * Attempt to spin the disc. New PC drives can tell by the acceleration of the spindle whether there is a disc present or not, although I doubt an 80's player will do this. If there is no disc present according to this check then stop. * While spinning turn the laser on and try and catch focus (apply a ramp signal to the focus actuators) * If focus is caught turn on radial feedback loops * Go and find the TOC etc... All players / drives will always home the OPU before trying to catch focus as the outside of the disc may contain no data (or it may be of the 8cm type). So by the sounds of your problem the motor, motor driver or motor driver supply section is bad. Martin. "Mark D. Zacharias" wrote in message ... Your friend is wrong. It must focus FIRST, then spin the disc. Focus fails, no spin. Quite possibly a bad laser pickup. At the moment it "should" spin, try helping the disc spin by giving it a push. May take a couple tries. If it takes off, even spinning weakly, the spindle motor is bad. Sometimes they can be fixed by spraying the brushes with cleaner. Let us know and if this is the case maybe we can walk you through it. Mark Z. "Erik" wrote in message om... I forgot to mention that I checked all leads to pickup and motor, they are ok. However, there is no voltage at the terminal the motor connects to, probably the same thing for the coils at the trackingdevice connection. When it tries to focus, I can see a dim red light, apparently the laser is ok. There are a couple of boards in the unit, but in this case I think a part of the RF/SERVO(f) board is likely to be failing, the board is in two parts, the part where both the motor and tracking connects to is a vertical mounted little board on the larger mainboard, where the other cables from the pickup goes to. Hope you can help me on this one. Thanks in advance, Erik |
#5
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"news-proxy.pgb.philips.com" martin@nowhere wrote in message ... Most systems will spin the disc then focus (this certainly applies to all Philips units - in fact I've never seen a system that does otherwise). Actually, I was working on a Marantz (Philips made) today for a power supply problem and I am pretty sure that it focuses first then spins the disc like most of the other players that we work on. I think Mark is right on this one (as he usually is). Leonard |
#6
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"Leonard Caillouet" wrote in message news:u4Otd.319$vC.41@lakeread06... "news-proxy.pgb.philips.com" martin@nowhere wrote in message ... Most systems will spin the disc then focus (this certainly applies to all Philips units - in fact I've never seen a system that does otherwise). Actually, I was working on a Marantz (Philips made) today for a power supply problem and I am pretty sure that it focuses first then spins the disc like most of the other players that we work on. I think Mark is right on this one (as he usually is). Leonard Philips may have some exceptions. I was over-generalizing. Older players often have separate disc sensors, and many carousel changers do as well. The majority of single disc players, including CD-ROM drives, simply use the focus routine to detect the disc. Mark Z. |
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