Stentofon MPC52 - 720 / Vingtor Marine VMP52 - 120 , a widely used intercom system.
Outranged in 1992, the factory production of service boards stopped in dec. 2002. But this high quality system is still repairable .
Stations without display only. Connected to AB board .
Stations with or without display . Connected to ABD board.
To avoid unlogic behaviour and blown boards, all voltages inside the exchange must float measured to electrical GND . Voltages are easy to measure at the power supply terminals.
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About soldering tools : Transformer insulated and temerature controlled soldering iron only , set temp to around 275 deg. Celsius
General programming preparation , what must be known before programming .
Sorting out what's inside the exchange : Version of running software on the proccessor board., standard boards / extra function boards, internal wireing schematic to local terminal numbers .
What's connected to the exchange : stations , stations catalog number , remote equipment and other hardware connected , ref. to terminal numbers inside the exchange .
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The programming :
This part is best solved by a trained programmer combining the use of a pc with different programming and logging tools, and a programming panel . If handshake circuits is missing , just add it . And the software has to be replaced to corresponding handshake software . The PMD ver. Lxx or 2.2 allready have handshake enabled .
Using a programming panel : Make direct addressed programming by entering line numbers in different system tables and at these addresses write 16bit - 4 letter hex code with special meaning . Parts of the exchanges programming are available only by using this programming panel . To make meaningful programming it's a must to have good knowledge in system software organization and hardware functions .
Programming from a station. Easy programming of catalog numbers for one type of stations, but only a little part of the total programming is available.
We'll do the programming : Send us the PMD/PMC board , the program journal and a list of wanted program changes . We'll program it and return the board w/ a new backup battery installed .
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Important reading.
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The most important notice!
Note! " Power OFF when plugging !
Like replacing boards in a computer , to avoid serious damage on the exchange electronic boards allways turn off the power before replacing any board in the exchange !!.
The printed circuit board of the AB-board ( 61019 ) with surface mounted micro-components acts like a heatsink and some dark marks tells us about high temperatures on the PCB surface. Dried out electrolytic capacitors is a common problem . A service tip : Lift all electrolytic capacitors to avoid direct contact with the hot PCB surface , then the AB-boards will work properly several times longer .
If "hotplugged" this 61019 AB board will be damaged ( normally beyond repair ), also expect damage on other AB / CLM boards .
About CLM boards : Mostly minor faults . Obsolete, but repairable . A typical problem > Only a low beep while pressing a numeric button on a station > No connection . Or if one or more Ab-boards has been "hotplugged" also the CLM board may crash , noise only while pressing a numeric button is a typical symptom .
About DCB / DPB boards: The nonvolatile sram programming of this board is not an easy task , it's smart to have all DCB / DPB programming written down in a programming journal .
If the DCB / DPB program is all lost , in most cases a trained expert must examine the excange , the DCB / DPB connections and software to compose a new programming .
Lifetime of the Lithium backup battery on the DCB / DPB board is 10 years and it must be replaced while the DCB / DPB board is still working ! Look for the production year & week , written or stamped on the lithium battery .
If battery is old send us the DCB / DPB board to make a complete data backup , before any attempt to replace this old lithium cell . Do not replace this battery yourself , the programming will be lost !
Some parts are obsolete , like the TMS9902 circuit .
About FFT boards : Mostly minor faults . Obsolete, but repairable . Ask us .
About FLX / LEX / LUX : Mostly minor faults . Some obsolete parts. Ask us .
About PMI boards : No problems or faults . Some hot areas , resistors should be lifted to avoid damage to the PCB .
About PWR supplies : Overheating , fans are not working , dried out capacitors , noicy stations , unstable exchange function . Note! Some Vingtor VMP52 / VMP120 PWR 's have no +5VDC overvoltage protection !
About SB boards: No problems or faults . Some hot areas , resistors should be lifted to avoid damage to the PCB .
About SB4 boards: No problems or faults . Fix Xtal to the Printed Circuit Board ( PCB) surface.
About SCE boards: Minor problems. Fix Xtal to the Printed Circuit Board ( PCB) surface. Some parts are obsolete , like the TMS9902 circuit .
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Voltages measured inside a Stentofon MPC / Compact or Vingtor Marine VMP exchange must be floating , referred to mains ground . Measured voltage must roll towards zero . External components " like a telephone interface " often cause a voltage ref. problem .
Jo Tech Service specialities : some new / improved station functions are available with these systems.
Example: pa router ( MPC / VMP 52 - 120 )
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