10.2 Dual Charger - Panasonic EB-G450 Technical Manual
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Also See for EB-G450:
- Operating instructions manual (32 pages) ,
- Service manual (108 pages) ,
- Operating instructions manual (32 pages)
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ACCESSORIES
10.1.4 Test Points
TP No.
TP101
TP201
TP202
TP203
TP 300
TP301
TP302
TP304
TP305
TP306
TP307
TP309
TP310
TP311
TP312
TP313
10.1.5 Adjustment and Calibration
The adjustments that can be made on the handsfree unit are to the external power supply. These are made by
adjusting two variable resistors on the PCB. The procedure must be followed if the switching voltage regulator or
any other part of the external power supply is replaced.
10.1.6 Procedure
Connect up the Handsfree unit as for normal testing, but do not connect the Handheld unit. Measure the external
voltage power supply. Adjust R102 so that this voltage is 7.8V +/- 0.07V. Once the handheld unit is connected and
in a call R144 is used to adjust the maximum current supplied.
10.2 Dual Charger
10.2.1 Circuit Description
A battery present is detected by the TH input, and battery type is detected by the S input. The S input is open-
circuit on a small battery, pulling the base of Q13 high, turning it off. The base of Q2 is pulled low through R24,
turning Q2 ON. This switches the extra control resistor VR1 into circuit, increasing the timer clock rate. VR2 is used
to control the clock rate when a large battery is connected.
Issue 1
Revision 0
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DESCRIPTION
Switching Voltage Regulator
External power
nLogic Power
Battery + (car)
TX Audio (To the handheld unit)
Output Amplifier Power
GND
RX Audio (To the handheld unit)
Audio GND
nHF on
Mic override speaker
Audio GND
Mic
Speaker
Audio GND
U306 pin 3 HCL
BOARD LOCATION
U102 Pin 2
P201 Pin 15
P201 Pin 14
P203 Pin 1
P201 Pin 3
Q205 Pin E
U308 Pin 3
P201 Pin 4
P201 Pin 5
P201 Pin 7
R355, R309
P301 Pin 2
P301 Pin 1
J300 Pin 2
J300 Pin 1
U306 Pin 3
Section 10
10 - 4
MCUK971001G8
Technical Guide
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