Instruction/ maintenance manual of the product MPI-II VHF Ericsson
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Mobile Communicatio n s SER VICE SECT ION FOR M P I -I I VH F P E RS O NA L RA D I O Printed in U.S.A. Copyright January 1991, E ricsson G E Mobile C ommunications, Inc.
INTRODUCTION This se r vice secti on c ontains the necessary information to ali gn and troublesh oot the MPI-II (1 36-174 MHz) Per- sonal Radio. This manual includes steps for disassembly and procedures for replacing surface mount components and integrated circuits.
FRONT COVER 1. Remov e th e bat tery a s describ ed in the previo us section. 2. Remove the tw o scr ews at (A) ( S ee F igure 2). 3. Caref ull y lift the f ron t co ve r from the r ad io . 4. Unplug t he ca ble betw een the front cover MIC B oard and the T/R B oard .
Severa l tests are presented which will help isol ate a pos- sible RF o r control circuit problem. The control circuits , which are l ocated on the T / R Board, contain no adjustments and there is n o alignment required for the control circuits.
Figure 4 - Location of Tuning Controls and Test Points LBI-38557 LBI-38557 4.
2. Check power on the lower channel . A djust C124 in the direction that increases powe r output to a level half way betw ee n t he i niti al low er a nd u p pe r ch an nel levels. 3. Rechec k the upper channel po wer. If the u pper ch annel power is r educe d , r eset to th e prev ious le vel by adjust- ing C126.
3. Check for proper operat ion of the synthesizer. Th ere should be approxim ately 0 dBm d rive level on the SYNTH output li ne for proper transmit operation. If a Syntheiszer problem is suspected, followin g the suggestions in Troubleshooting S ynthesizer s ection.
D.C. Analysis Battery voltage (7.5/10 V olts, B+) is supplied to a 5.4 volt regula t or circuit consisting of transistors Q801, Q802 and Q803. Diode re gulator U801 provides a 2.5 volt reference for this circuit. Battery voltage (B+) is also supplied to the Syn- thesizer Board for isolation a mplifie r U206.
SURFACE MOUNT COMPONENT REPLACEMENT 1. "Tin " one te rmina l en d o f the ne w compon ent an d the corresponding pad of the P WB. Use as little solder as possible. 2. Plac e th e com ponen t on th e PWB p ads, o bservin g prope r ori enta tio n for capa cito rs, diod es, transistors, etc.
2. A full ch arge c ycle using an appropria te Eric s so n GE charge r. 3. This p roce dure should be r epeated a gain. P erfor ming the rated discharge and charge cycle a t least twice should sufficiently rest or e the battery .
An important point after buying a device Ericsson MPI-II VHF (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Ericsson MPI-II VHF yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Ericsson MPI-II VHF - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Ericsson MPI-II VHF you will learn all the available features of the product, as well as information on its operation. The information that you get Ericsson MPI-II VHF will certainly help you make a decision on the purchase.
If you already are a holder of Ericsson MPI-II VHF, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Ericsson MPI-II VHF.
However, one of the most important roles played by the user manual is to help in solving problems with Ericsson MPI-II VHF. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Ericsson MPI-II VHF along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
