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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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Basic CD player in a micro music centre
No movements or laser light , totally dead CD player. Just -- in the
display. Function sw and door latch sw ok. Plenty of 5V etc supplies around on the chippery. Crystal and ceramic resonator have oscillation. All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable is set off ie operational. Pressing all sm chip leads , no change Swapping laser and carrier/motors section with another one laying around, the same zilch. No dodgy electrolytics. Is there something obvious I'm overlooking ? Not worth spending a lot of time on but a good customer for other stuff. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#2
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Basic CD player in a micro music centre
"N Cook" wrote in message ... No movements or laser light , totally dead CD player. Just -- in the display. Function sw and door latch sw ok. Plenty of 5V etc supplies around on the chippery. Crystal and ceramic resonator have oscillation. All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable is set off ie operational. Pressing all sm chip leads , no change Swapping laser and carrier/motors section with another one laying around, the same zilch. No dodgy electrolytics. Is there something obvious I'm overlooking ? Not worth spending a lot of time on but a good customer for other stuff. Can't think of anything that you seem to be overlooking. First place I would have gone is the same as you - to the door switch. Even though the switch is working ok in itself, I would still feel inclined to make sure that its connections are making it all the way back to the micro, and doing something ie pulling a pin to ground or whatever. I've had internal pull-up resistors on micro pins fail. The only other thing that it's worth doing when all else has failed, and you've given up, is to try a possible 'real' system reset, by holding in the power button and applying power, and if that fails, a 'naughty' engineer's reset, by turning off and removing power, then hooking a croc lead to ground, and stroking round every pin of every 'micro-ish' IC both on the front panel, and the CD process board. I've known this to restore screwed up system controls on a number of occasions. I got it originally from a manufacturer's training course, but so far back in the dim mists of time, I can't remember which one now ... Arfa |
#3
Posted to sci.electronics.repair
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Basic CD player in a micro music centre
"N Cook" wrote in message ... No movements or laser light , totally dead CD player. Just -- in the display. Function sw and door latch sw ok. Plenty of 5V etc supplies around on the chippery. Crystal and ceramic resonator have oscillation. All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable is set off ie operational. Pressing all sm chip leads , no change Swapping laser and carrier/motors section with another one laying around, the same zilch. No dodgy electrolytics. Is there something obvious I'm overlooking ? Not worth spending a lot of time on but a good customer for other stuff. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Don't forget the sled limit switch - brand and model info might help. Mark Z. |
#4
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Basic CD player in a micro music centre
Arfa Daily wrote in message
... "N Cook" wrote in message ... No movements or laser light , totally dead CD player. Just -- in the display. Function sw and door latch sw ok. Plenty of 5V etc supplies around on the chippery. Crystal and ceramic resonator have oscillation. All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable is set off ie operational. Pressing all sm chip leads , no change Swapping laser and carrier/motors section with another one laying around, the same zilch. No dodgy electrolytics. Is there something obvious I'm overlooking ? Not worth spending a lot of time on but a good customer for other stuff. Can't think of anything that you seem to be overlooking. First place I would have gone is the same as you - to the door switch. Even though the switch is working ok in itself, I would still feel inclined to make sure that its connections are making it all the way back to the micro, and doing something ie pulling a pin to ground or whatever. I've had internal pull-up resistors on micro pins fail. The only other thing that it's worth doing when all else has failed, and you've given up, is to try a possible 'real' system reset, by holding in the power button and applying power, and if that fails, a 'naughty' engineer's reset, by turning off and removing power, then hooking a croc lead to ground, and stroking round every pin of every 'micro-ish' IC both on the front panel, and the CD process board. I've known this to restore screwed up system controls on a number of occasions. I got it originally from a manufacturer's training course, but so far back in the dim mists of time, I can't remember which one now ... Arfa Perhaps stripping off at midnight and dancing around it on a full moon might work as well. |
#5
Posted to sci.electronics.repair
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Basic CD player in a micro music centre
"N Cook" wrote in message ... Arfa Daily wrote in message ... "N Cook" wrote in message ... No movements or laser light , totally dead CD player. Just -- in the display. Function sw and door latch sw ok. Plenty of 5V etc supplies around on the chippery. Crystal and ceramic resonator have oscillation. All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable is set off ie operational. Pressing all sm chip leads , no change Swapping laser and carrier/motors section with another one laying around, the same zilch. No dodgy electrolytics. Is there something obvious I'm overlooking ? Not worth spending a lot of time on but a good customer for other stuff. Can't think of anything that you seem to be overlooking. First place I would have gone is the same as you - to the door switch. Even though the switch is working ok in itself, I would still feel inclined to make sure that its connections are making it all the way back to the micro, and doing something ie pulling a pin to ground or whatever. I've had internal pull-up resistors on micro pins fail. The only other thing that it's worth doing when all else has failed, and you've given up, is to try a possible 'real' system reset, by holding in the power button and applying power, and if that fails, a 'naughty' engineer's reset, by turning off and removing power, then hooking a croc lead to ground, and stroking round every pin of every 'micro-ish' IC both on the front panel, and the CD process board. I've known this to restore screwed up system controls on a number of occasions. I got it originally from a manufacturer's training course, but so far back in the dim mists of time, I can't remember which one now ... Arfa Perhaps stripping off at midnight and dancing around it on a full moon might work as well. Only if it's a Philips ... Arfa |
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