Opweb.de

1.1 CONTENTS This service manual contains instructions for troubleshooting and repairing the EM 3031, EM 3032 and EM 3532 Mikroport receivers. A repair of the EM 3031, EM 3032 and EM 3532 Mikroport receivers can be carried out by replacing the respective subassembly or assembly. This form of repair has proved its worth in practical use, and it restricts the necessary functional knowledge to the subassemblies. With suitable measuring and test equipment, the assembly can be repared down to the component level. Circuit diagrams, wiring diagrams and block diagrams are included in the section "SCHEMATICS". 1.1.1 INFORMATION ON THE SECTIONS - General Section 1.1 explains the concept of the service manual and helps the user to become acquainted with the individual sections. - Operating elements The operation of the receivers is briefly explained; a thorough knowledge of the subject area is assumed. - Technical data This section lists the technical data of the EM 3031, EM 3032 and EM 3532 Mikroport receivers. - Measuring and test equipment Here, all the service tools that are necessary for alignment, repair or frequency changes are listed. - System overview The function of the assemblies within the EM 3031, EM 3032 and EM 3532 Mikroport receivers are described in this section. - Service instructions This section describes general testing, testing of the reception qualities, alignment and troubleshooting, error messages, and hints for troubleshooting. In addition, measures are described to locate defective components. - Changing the receiving frequencies Here, detailed information is given on programming the receiving frequencies via the service/programming socket. This section also describes how to change the receiving frequencies within the defined switching bandwidth, outside the switching bandwidth and how to replace the tuner assembly. - Test and alignment instructions This section describes the test set-up, the localisation of assemblies and the test and adjustment instructions (with oscillograms for signal tracing). - Schematics This section contains all wiring diagrams, circuit diagrams and block diagrams of the assemblies of the EM 3031, EM 3032 and EM 3532 Mikroport receivers. - Modifications Technical modifications affecting the content of this service manual will be distributed to the users as service information 1.2 SERVICING 1.2.1 MIKROPORT ASSEMBLIES Some of the printed circuit boards are multi-layer PCBs and can be irreparably damaged by improper repair or handling. 1.2.2 SERVICE MANUAL This service manual is intended for technicians to enable them to carry out the most important repairs and alignments. If necessary, the manual can also be given to the customer. 1.2.3a)b)c)d)REPAIR If repair is to be carried out by replacing an entire assembly, it must be carried out as follows: - IF assembly, Diversity assembly, HDP assembly, Processor assembly, Display assembly If repair is not to be carried out by replacing an entire assembly, the device must be repaired at the component level using the service manual. - Main printed circuit board (PCB) If repair is to carried out either by replacing an entire component or by a repair at the component level, this is at the discretion of the service technician. - Tuner assembly Fast service means that all assemblies on the spare parts list have to be held in stock. They can be ordered from the Sennheiser Service Department. 1.2.4 SMDs (Surface Mounted Devices) The PCBs of the EM 3031, EM 3032 and EM 3532 Mikroport receivers are predominantly populated with surface mounted devices (SMDs). Any SMD damaged during handling must be replaced. SMDs are directly soldered onto the provided substrate lands. Their end caps have a solderable coating and are largely insensitive to heat. To replace SMDs, the following tools are needed: in addition to a pair of tweezers and a normal, temperature-controlled soldering iron (e.g. Weller with a 0.8 mm flat-headed soldering bit PT-H 7 or a 0.8 mm long-headed soldering bit PT-K 7), you should have a suction device that is absolutely blow-back proof and1.2 mm unsoldering wire. It is also advisable to use a magnifying glass. The soldering time should be kept as short as possible to ensure that the conductors are not damaged. Especially when unsoldering the components, care must be taken that the solder tracks are not lifted off. After soldering, the contact surface of the components must be cleaned from solder residue. To avoid mechanical stress within the components, solder one side first, then wait until this joint has cooled down before soldering the opposite side. It is not permissible to reuse components that have previously been unsoldered, even if the component looks faultless. During soldering and unsoldering, the component is subject to thermal stress, so damage cannot be excluded. SMDs are supplied as spares in packs of 50. Containers used to stock parts have to be unambignously labelled, as itotherwise not possible to distinguish the components.