Grundig CD 8400 MKII "DISC"
I have a Grundig CD 8400 MKII and about a month ago the sound output went dead. I found that the TDA 1541A was dead. I replaced it with TDA 1541 without the "A" and also replaced the SAA 7220 to SAA 7220 P/A. It worked fine. But when i assembled the player i switched it on and it didn't wanted to read any disc. It displayed "DISC" on the display. I opened and i discovered that there was a desoldered wire from the laser to the main PCB. I soldered it and it worked. But when i closed it the same problem appeared. now i can't figure out what's the problem??? I discovered that the "LASER-SUPPLY" trimer isn't responding - when i turn it the laser beam is the same. And also when i leave the player all of the IC's are becoming hot except the one for the laser control TDA 5708. I downloaded the data sheet and it says that it should have VDD 8-12 V and VCC 8-12 V measured from PIN 15-2 and PIN 15-28 but from my measurements it has VDD 5.7 V and VCC 4.6 V. I can't figure out what went wrong and i cant find the fault??? Please help!
I have a Grundig CD 8400 MKII and about a month ago the sound output went dead. I found that the TDA 1541A was dead. I replaced it with TDA 1541 without the "A" and also replaced the SAA 7220 to SAA 7220 P/A. It worked fine. But when i assembled the player i switched it on and it didn't wanted to read any disc. It displayed "DISC" on the display. I opened and i discovered that there was a desoldered wire from the laser to the main PCB. I soldered it and it worked. But when i closed it the same problem appeared. now i can't figure out what's the problem??? I discovered that the "LASER-SUPPLY" trimer isn't responding - when i turn it the laser beam is the same. And also when i leave the player all of the IC's are becoming hot except the one for the laser control TDA 5708. I downloaded the data sheet and it says that it should have VDD 8-12 V and VCC 8-12 V measured from PIN 15-2 and PIN 15-28 but from my measurements it has VDD 5.7 V and VCC 4.6 V. I can't figure out what went wrong and i cant find the fault??? Please help!
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