Motorola Radio Mcs2000 Vol 1 68p81083c20 A Manual

 
Troubleshooting9-15 
-Check that U0653 pin 52 is 5 VDC with pulses to ground while transmitting data. Then check U0655 
(disconnect pin 1). If problem disappears and OPTION SW B+ circuit is OK (see 5.), replace U0655. If the 
OPTION SW B+ circuit is defect, D0684 should also be checked. 
4.2SB9600 BUS-, J650 pin 4 
-This signal is normally 0 V with short pulses to 5 VDC when data are sent on the bus. If it is constantly 5 
VDC or 0 V, check D0678 (most common error), Q0657 and Q0656. 
-Check that U0653...

 
9-16Troubleshooting 
-Connect a 68 ohm resistor from P0651 pin 1 to ground.
-Check that the DC voltage on P0651 pin 1 is still approx. 12 VDC.
-If not check Q0662. 
5.8Multiplexer in SB9600 position 
-Connect a 5.6 kohm resistor from P0651 pin 1 to ground (a keypad microphone can be used instead).
-Check that the voltage on U0655/U0656 pin 10 is 0 VDC.
-If this fails check Q0662 and Q0663. 
6Volume Control 
-Turn R0698 fully counter clockwise and then fully clockwise and verify the voltage on U0653 pin...

 
Troubleshooting9-17 
10.2One/some LEDs 
-One LED is off. Check the LED.
-One row of LEDs is off. Find the LED that makes the short circuit.  
11LCD
11.1Defect outside segments of display 
-If the LCD has either light or dark areas outside the segment, the LCD glass is defect and must be 
replaced. 
11.2Missing segments 
-Missing segments. Most likely a bad connection between PCB and LCD. Disassemble and clean PCB and 
zebra connector with alcohol. LCD glass surfaces can be cleaned with distilled water...

 
9-18Troubleshooting 
Troubleshooting Chart 1-8B, Control Head Models II & III  
Numbers in brackets refer to accompanying troubleshooting procedure overleaf
Radio
can turn on/off?
(1.1)Check on/off switch (1.1)No
Yes
Radio
resets control
head?
(2.1)Error in radio!No
Yes Yes
5VDC
on TP3?
(1.2)Check 5V supply (1.2)No
Reset
circuit works?
(2.2)Check Q0655, U0660,
D0660 (2.2)No
Yes
Keypad
OK?
(7)Check electrical connection to µP.
Clean PCB or replace keypad (7)No
Yes Yes
Check R0697 (14) Volume
control...

 
Troubleshooting9-19 
Control Heads 
II and III Troubleshooting Procedure 
1Power Supply 
Check that the radio is connected to a power supply. 
1.1ON/OFF switch 
-Check that radio turns on. I.e. SW B+ is 12V DC. If not, press the ON/OFF switch to turn off radio.
-If the radio does not turn on, verify that there is DC voltage on the MIC-HI/ON_OFF line and that this 
voltage goes to ground when pressing the ON/OFF switch.
-If the DC voltage is present but does not go low check J0650 and R0696. 
1.25V DC...

 
9-20Troubleshooting 
4.1SB9600 BUS+, J650 pin 15 
-This signal is normally 5 VDC with short pulses to 0V when data are sent on the bus. If it is constantly 0 
V or 5 VDC check D0665 (most common error), Q0663 and Q0662. Check that U0653 pin 52 is 5 VDC 
with pulses to ground while sending data.
-Then check U0659 (disconnect pins 1 and 12). If problem disappears and OPTION SW B+ circuit is OK 
(see 5.), replace U0659.
-If the OPTION SW B+ circuit is defect, D0669 should also be checked. 
4.2SB9600 BUS-,...

 
Troubleshooting9-21 
5.4Monitor input 
-Check that the voltage on U0653 pin 9 changes from 5 VDC to approx. 3.3 VDC when P0651 pin 3 is 
connected to ground.
-If this fails check U0658. 
5.5AUX input 
-Check that the voltage on U0653 pin 5 changes from 5 VDC to approx. 0 VDC when P0651 pin 7 is 
connected to ground.
-If this fails check U0659. 
5.6SW B+ in SB9600 mode 
-Connect a 5.6 kohm resistor from P0651 pin 1 to ground (a keypad microphone can be used instead).
-Check that the DC voltage on P0651...

 
9-22Troubleshooting 
-Check Q0657 (yellow), Q0658 (red) and Q0659 (green).
-Check LEDs. 
10LCD backlight
10.1All LEDs 
If backlight cannot be turned on or off.
-Check that U0654 pins 16 and 19 are 5 VDC.
-If not, check U0654.
-Check that the voltage of base on Q0666 is 5 VDC.
-Check that the DC voltage of U0656 pin 1 is approx. 4.3 V.
-Check Q0667 and U0656. 
10.2One/some LEDs 
-One LED is off. Check the LED.
-One row of LEDs is off. Find the LED that makes the short circuit. 
11LCD
11.1Defect outside...

Troubleshooting9-23
13.1Secure keyloader sensing
-Connect P0651 pin 2 to ground. Check that DC voltage on U0653 pin 4 goes to 0 V. If not, check P0651, 
R0690, R0691 and C0667.
13.2Multiplexer in keyload position
-Check that U0654 pin 5 goes to 5 VDC. If not check U0654.
13.3Connections through multiplexer
-Check that P0651 pins 6, 3 and 7 are connected to J0650 pins 10, 12 and 11 respectively. If not check 
U0657, U0658 and U0659.
-Also check D0666, D0661, D0667, D0668, D0669, D0721 and D0722.
14Rotary...

9-24Troubleshooting
Troubleshooting Chart 1-9, Clock Distribution 
CHART 1-9   CLOCK DISTRIBUTION
No
Yes16.8MHz
on U5801-14
No
Yes2.1MHz
on U0200-E1
No
Yes3.68MHz,
or 7MHz, or 14 MHz
on U0200-D1
No
YesFrequency
on U0200-D1 divided
by 4 on 
U0103-34
Check
U0104
Check
U5800,
C5754, R5750 
Check
U5801,
R5759, C5768
Check
U0200,
R0204, L0200,
C0208, R0200 
Check
U0103
Yes
No
Frequency on
U0200-D1 on U0104-A3
and Frequency on U0200-D1
divided by 4 on
U0104-A4Check
U0103
START