© Bosch Security Systems, Inc., 2014
12000 Portland Ave S., Burnsville, MN USA
www.rtsintercoms.com
RTS-TB-030
Technical Bulletin
25-June-2014
Page 2 of 7
3.0 Detailed Rework Instructions
NOTICE!
The following rework should only be performed by qualified repair personnel
operating according to proper safety, ESD and soldering practices
____________________________________________________________________________
Necessary rework equipment (no electrical parts are necessary):
Small flat blade or jeweler's screwdriver
Magnifying glass (if required for improved visibility)
Digital Multimeter / Ohm-meter
The odd channels on the AIO-16 (1, 3, 5, 7, 9, 11, 13 and 15) follow the same layout topology around the op-
amps on the PCBA. The even channels on the AIO-16 (2, 4, 6, 8, 10, 12, 14 and 16) follow the same layout
topology around the op-amps on the PCBA. For this reason, a detailed description is given for the calibration
of the potentiometers associated with channels 1 and 2. This same methodology can then be repeated for
the remaining odd and even channels.
3.1
Rework for Channel 1
In the schematic below, locate potentiometer R105, 19.6 kOhm resistor R104 and 20 kOhm resistor R106.
During the manufacturing process, the potentiometers (R105 in this example) were not properly calibrated.
To achieve optimal common mode rejection of noise, the potentiometer R105 must be adjusted so that the
sum of R104 + R105 = R106 within 40 Ohms.