NAD-T762-avr-si2 维修电路原理图.pdf

Service Information T762 Software Upgrade (Revised) The following procedure details how to upgrade the T762 software. Determine software version. 1. Turn on the unit and then select an input (eg. DVD) 2. Now press the AUDIO and VIDEO buttons at the same time for 1-2 seconds. 3. The version of software will appear in the display eg. 1.18 or 1.20. Replacing the microprocessor (see attached photo) 1. Remove the top cover. 2. The front panel is easily removed. The top of the front panel is held in place with four screws on top and five on bottom. 3. Once the screws are removed pull the front panel forward and unplug the ribbon cable on your right side and the four pin connector as well. 4. Unplug the three pin and eight pin cables on the left side. 5. The microprocessor can now be removed. 6. Locate U201, see diagram for reference. 7. Using a PLCC extractor tool remove the microprocessor. (Dont use a screwdriver as this may crack the socket!) 8. When inserting the microprocessor line up the dot on the top with the arrow on the socket. 9. Reconnect the cables and secure the front panel. NOTE (see schematic of reset circuit) If after upgrading you find that the unit wont turn on then try replacing the zener diode D213 located on the front panel from 6.2v 1/2W with the value of 2.7 v 1/2W. This improves the reset timing. /2 RadioFans.CN 收音机爱 好者资料库 RESETTING T762 Resetting the T762 after this procedure is required, perform the following as described below. North American units “AH” The T762 can be reset by pressing the VIDEO and the TONE DEFEAT buttons at the same time for 1-2 seconds. ALL Other Countries “C” The T762 can be reset by pressing the VIDEO and the TONE CONTROLS buttons at the same time for 1-2 seconds. Photo of U201 Schematic of Reset Circuit Contact: NAD Electronics International 10/07/03 RadioFans.CN 收音机爱 好者资料库