Function Key Leds Or Status Leds Faulty; Circuit Diagram Of The Function Key Leds And Status Leds - Tait TM9100 Service Manual

14.6

Function Key LEDs or Status LEDs Faulty

The function key LEDs (F1 and F4) and the red, green and amber status
LEDs each are controlled by an FPGA signal and a transistor (Q604 to
Q608). The brightness level is controlled by two FPGA signals, resulting in
four intensity levels (off, low, medium and high).
Figure 14.5

Circuit diagram of the function key LEDs and status LEDs

R601
IND BRIGHT1
R602
IND BRIGHT2
FPGA
LED FUNC 1
LED FUNC 4
LED IND TX
LED IND RX
LED IND BUSY
If one of the function key LEDs or status LEDs is faulty:
LED Faulty
1.
2.
3.
4.
If the intensity of the LEDs is faulty:
LED Intensity Faulty
1.
2.
406 Fault Finding of Control Head
3V3 3V3
R34 R35
0 0
F1 Key F4 Key
D613 D614
Q604 Q605
R603 R604 R605
Send CCTM command 1001 x 1 (where x is the LED number:
0=F1, 1=F4, 2=amber, 3=green, 4=red) to activate the relevant
LED.
Check the resistors R34, R35, and R36 in the paths of the green
LEDs.
R34: 0Ω
R35: 0Ω
R36: 0Ω
Measure the voltage at the point between the LED and the transistor.
D613/Q604 (F1 key LED):
D614/Q605 (F4 key LED):
D615/Q606 (red status LED):
D616/Q607 (green status LED):
D617/Q608 (amber status LED):
If the voltage is incorrect, replace the LED.
Replace the corresponding transistor.
Send CCTM command 1001 0 1 to activate the LED of the F1 key.
Send CCTM command 1002 3 to set the LED intensity level to high.
3V3
3V3
R36
0
Red D615 Green D616
Q606 Q607
R609 R612
1.87V (on) 1.40V (off)
1.87V (on) 1.40V (off)
1.92V (on) 1.57V (off)
1.87V (on) 1.40V (off)
1.89V (on) 1.48V (off)
TM9100 Service Manual
© Tait Electronics Limited August 2005
3V3
Amber D617
Q608
R616