Yaesu FT-897 Technical Supplement

Also see for FT-897: Manual Brochure & specs Operating manual Service manual Operating manual

Contents

10AlignmentIntroduction and PrecautionsThe following procedures cover adjustments that arenot normally required once the transceiver has left thefactory. However, if damage occurs and some parts sub-sequently be replaced, realignment may be required. If asudden problem occurs during normal operation, it is likelydue to component failure; realignment should not be doneuntil after the faulty component has been replaced.We recommend that servicing be performed by autho-rized Vertex Standard service technicians, experiencedwith the circuitry and fully equipped for repair and align-ment. If a fault is suspected, contact the selling dealer forinstructions regarding repair. Authorized Vertex Standardservice technicians have the latest configuration informa-tion, and realign all circuits and make complete perfor-mance checks to ensure compliance with factory specifi-cations after repairs.Those who do undertake any of the following align-ments are cautioned to proceed at their own risk. Prob-lems caused by unauthorized attempts at realignment arenot covered by the warranty policy. Also, Vertex Standardmust reserve the right to change circuits and alignmentprocedures in the interest of improved performance, with-out notifying owners.Under no circumstances should any alignment be at-tempted unless the normal function and operation of thetransceiver are clearly understood, the cause of the mal-function has been clearly pinpointed and any faulty com-ponents replaced, and the need for realignment determinedto be absolutely necessary.The following test equipment (and thorough familiar-ity with its correct use) is necessary for complete realign-ment. Most steps do not require all of the equipment listed,but the interactions of some adjustments may require thatmore complex adjustments be performed in a sequence.Do not attempt to perform only a single step unless it isclearly isolated electrically from all other steps. Rather,have all test equipment ready before beginning, and fol-low all of the steps in a section in the order they are pre-sented.Required Test Equipmentm Digital DC Voltmeter (high-Z, 1 M-Ohm/V)m DC Ammeterm RF Millivoltmeterm AC Voltmeterm RF Standard Signal Generator w/calibrated output anddB scale, 0 dBμ = 0.5μVm Signal Generator with calibrated outputm Spectrum Analyzer good to at least 1 GHz.m Frequency Counterm 50-Ohm Dummy Load (200 watts)m 100-Ohm Dummy Load (200 watts)m 150-Ohm Dummy Load (200 watts)m In-Line Wattmeter (200 watts, 50-Ohm)m Linear Detectorm RF CouplerAlignment Preparation & PrecautionsA 50-ohm RF Dummy load and in-line wattmeter mustbe connected to the main antenna jack in all proceduresthat call for transmission, except where specified other-wise. Correct alignment is not possible with an antenna.After completing one step, read the following step todetermine whether the same test equipment will be re-quired. If not, remove the test equipment (except dummyload and wattmeter, if connected) before proceeding.Correct alignment requires that the ambient tempera-ture be the same as that of the transceiver and test equip-ment, and that this temperature be held constant between68°~ 86°F (20° ~ 30°C). When the transceiver is broughtinto the shop from hot or cold air, it should be allowedtime to come to room temperature before alignment.Whenever possible, alignments should be made withoscillator shields and circuit boards firmly affixed in place.Also, the test equipment must be thoroughly warmed upbefore beginning.Note:Signal levels in dB referred to in this procedure arebased on 0 dBμ = 0.5 μV (closed circuit).