The most important notice!

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 !!


Important !!     Data security / disaster recovery of userspecified programming :  

If the backup battery / accu is older than 10 years expect program loss, also at  a short time main voltage drop .

The ACM board has short  battery lifetime . Remember to backup to onboard eeprom .

Expect the lifetime of a lithium battery and a nonvolatile sram circuit to be equal or less than 10 years in ambient battery temperature up to approx 40 degrees centigrade . Look for the production year/week on the battery / nonvolatile sram (w/it's own built in lithiumbattery).  

Look for the production year/week written /stamped on the lithium battery .

Processor boards: PMC, PMD, PMF, PMF-R , ACM all have backup NiCad accu battery and PMF-R also have nonvolatile sram circuits ( max . 10 years lifetime) , DPB processor board have lithium battery .  

Note! If the charging voltage is missing a ( new ) NiCad accu vill discharge itself in less than a month .


Have a total backup at hand , and make program disaster recovery no big deal .

Send us the proccessor board ( PMC, PMD, PMF, PMF-R , ACM ) and a copy of the  PC backup , a copy of the programming journal is also ok . We'll repair / update / reprogram the proccessor board , and then return it with a new, fully charged backup accu battery .

To prevent program loss , the the proccessor board must be inserted in an exchange to have the onboard NiCad battery fully charged inside 2 weeks after the proccessor board  was shipped from us.


About proccessor boards and backup of userdata .

PMF, PMF-R and ACM boards have onboard eeprom(s) for backup / restore purposes.  It's important to have an up to date backup .   On the PMF-R board nonvolatile sram's must have it's own backup,  using an (e)eprom programming device is a simple solution .

The CPB-2 board have all userdata on eeprom and no battery. Backup userdata file to PC or use an (e)eprom programming device to make  a backup .

The PMC / PMD board has no onboard backup circuits. The programmer must backup all userdata to PC and write a programming journal .


NOTE!   Remember to have all programming written in a programming journal .

If possible also have a total chip backup performed on  nonvolatile sram's 
Note! Remember to make a backup of standard sram first .

Even if the exchange can be programmed using a PC , you must make a backup of all user-data .

Also make a complete backup of onboard eproms , eeproms and / or other running software .

NOTE! Standard sram circuits can not be removed from the board without loosing all its programming.

Contact us about backup of standard sram . Some boards have onboard eeproms for this purpose, some can be connected to a modem using remote backup & programming .


The backup of "eprom" , "eeprom" and "nonvolatile sram" is a fast & smart operation .  
Note! Remember to make a total backup of standard sram first .



Fix Xtal to the PrintedCircuitBoard ( PCB) surface .

program & memory . :  PMC / PMD / PMF / PMF-R / DPB / ( AMC )  proccessor boards w / backup batteries .  

control: ( PMC / PMD / PMF  / PMF-R ) If the LED = steady ON :  > proccessor is running , its likely  to belive that the board is operating OK .

Backup :   An up to date backup of the userspecified programming  is most important !

The backup-battery ( 3,6V NiCd ) on the proccessor board has approx.10 years  lifetime. If the intercom is dead or the userspecified programming is corrupted, also check this battery .  Shown here: a PMC/PMD  board , w / additional handshake hardware on the serial port to make programming  & backup easy  using a computer . Xtal must be fixed to the pcb surface , universal glue is ok

Note!  The userspecified programming is the most important ( and expensive ) part of the exchange , do not loose it .

On the proccessor board all userspecified programming must be saved before replacing  any IC's , the battery or any part in the battery carge circuit .  Don't perform any attempt  to repair this board yourself , call / mail us to help you .  

After losing or corrupting the  userspecified programming .  Special programming tools has to be used for reprogramming the exchange and the job has to be performed correctly . If there is no backup available expect days of work at the exchange even for an expert  to complete a total reprogramming .


Note! Warning !               Vingtor VMP 52 > 120    -     Stentofon MPC 52 > 720

The programselector  must stay in the OFF-position , all other positions are dangerous if you don't have a backup of your programming . In the ON-position you can alter the programming , in 52 or 112  position, you can rebuild the programming to the inital programming tables for a 52 numberexchange   or 112 - up numbers . All userdata will be lost in this operation , so you better not try it !!

Avoid corrupting the userspecified programming !  Setting the programselector in pos. 52 or 112 is banned  !!! 

If the exchange is not properly working and the purpose is to repair it , corrupting the userspecified programming most certainly is the wrong way to go !  Example:  If you set the programselector  of the exchange in pos. 52 or 112,  and push ( green ) and red button on the proccessorboard ,  the result is a total loss of the exchanges userspecified programming , all individually programmed functions will be wiped out , not only the numberseries are altered to a standard table .  Perhaps you know how to alter station numbers  , but what about groupcalls , call from one-button substations , telephone interface , amplified loudspeaker routing , different alarmsignals , bridge emergency microphone , baudrate setting ?    It's not possible to reprogram these functions from a station !!  Shit! what a big mistake to do .  


Jo Tech Service, Lykkmarka 53, 7081 Sjetnemarka, NORWAY. , , ( 47 ) 99718408

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Norway, Efjord