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E-200 SERIES INTERCOM SYSTEM — EF-200 DUAL CHANNEL MASTER STATION
9. REPAIR GUIDE
For service purposes, the unit must be opened removing the eight screws on the top cover.
NOTE:
This type of operations takes place with the unit open, for that purpose, it should be carried out
by a qualified technician.
DANGER:
Before opening the unit, disconnect it from the mains. It is important to indicate that
although the unit is switched off (with the power switch in 0 position), if it continues connected to the
mains, there are different parts of the unit that are subjected to high voltage.
CAUTION:
Protect the master station unit from the rain and moisture, mostly if it is open. If liquid is
spilled into the unit, disconnect it from the mains and consult a qualified service technician.
We recommend a meticulous visual exam before beginning to change anything in the unit:
burnt resistors, potentiometers with a broken trace, etc. This exam many times gives us the key for the
problem, saving time and unnecessary efforts.
Keep in mind when removing an element of the main board, that this is is a single layer printed
circuit, and the components PADs could get up if applies them an excessive heat. This is important
mainly in components having many pins (integrated circuits, connectors, etc.), for what it is
recommended to use a good desoldering station.
Next paragraphs details some of the most frequent breakdowns as a guide to the qualified
technical service helping to repair the unit:
If a fuse breaks due to a mains transient, replace it with the same ratings as described before
(make sure upon changing the fuse, that this is the adequate). In order to obtain more information,
consult the CHANGING THE FUSE section.
The battery power supply provide an internal fuse (FUSE), placed inside the unit, in order to
protect the unit of excessive currents in the battery. If it is necessary to change it because is broken,
make sure that the unit is disconnected from the mains, and open the top cover according to the
indications of the special operations section. The fuse is located in the top right corner, just beside the
fuse holder. Upon changing make sure that it is the appropriate T2A (2 ampere, slow rate).
The potentiometers have a limited live span; they are susceptible to become dirty and produce
noise upon moving them. It is important not to use sprays cleaners over the potentiometers, since
they can become damaged shortly. We recommend to clean it by compressed air only.
In order to change a potentiometer, the unit must be opened, removing the top and bottom
covers. To remove the front panel, extract all seven visible screws. The sub-panel behind the front
panel is joined to the chassis by six screws located at the chassis sides and by the potentiometers.
Special care must be taken when re-install the front panel because some delicate parts as the LED
lamps and keys must be introduced in small panel holes and it is a not an easy operation.
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