vizike 0 Posted September 28, 2009 Hi all, i have some avc787 dvrs and ineed for repair service manual and/or shematic draw. Please help me somebody! Thanks before Share this post Link to post Share on other sites
alexx 0 Posted September 28, 2009 Hi all, i have some avc787 dvrs and ineed for repair service manual and/or shematic draw. Please help me somebody! Thanks before No schemes, what are your problems with them, that does not work? Share this post Link to post Share on other sites
vizike 0 Posted September 29, 2009 No schemes, what are your problems with them, that does not work? By power on the dvr only beep. No start up. The motherboard have a IC with 5 pin U65 (ATV... I don't know the part No.) This IC make start up reset signal for U2 controller and more ICs over U64 hex inverter. No start-up by external high signal too. By first diagnostic: U2 contorller is bad. -> replace the IC but nothing change. The dvr beep continually. Very difficult the diagnostic without shematic. Share this post Link to post Share on other sites
scorpion 0 Posted September 29, 2009 Change the crystal, (or is that clock oscillator)?. It may, or maynot be part of the problem. Is it an H025, or the MCO1500A? What does the output look like on a scope? It might be a sloped square wave. I assumed you have checked all of the supply voltages? Share this post Link to post Share on other sites
vizike 0 Posted September 29, 2009 ...I assumed you have checked all of the supply voltages? Of course. the supply voltages are all right. But I dont know : what is the U65 IC (ATV...) I dont found datasheet. Share this post Link to post Share on other sites
alexx 0 Posted September 29, 2009 Yes, I understand. Himself doing repairs. I have the same problem AVC760. Try to do a system reset. but probably will not help ... You can try to overwrite the flash-memory ... check voltage 3,3 V and 1,8 V on-board Share this post Link to post Share on other sites
scorpion 0 Posted September 30, 2009 ...I assumed you have checked all of the supply voltages? Of course. the supply voltages are all right. But I dont know : what is the U65 IC (ATV...) I dont found datasheet. I am glad that you checked the power voltages with an oscilliscope. A multimeter can fool you as it will give you correct voltages, but the scope will show you AC leakage. AVTech DVRs hate AC leakage. I was hoping that buying a new external power supply would resolve your problem. ___________________________________________________________ Alex, I would say the same about your DVR. Try another power supply, and see what happens. Share this post Link to post Share on other sites
