Tait TM8115 Service Manual

414 Fault Finding of Control Head with Graphical Display TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
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).
LED Faulty If one of the function key LEDs or status LEDs is faulty:
1. 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.
2. Check the resistors R34, R35, and R36 in the paths of the green
LEDs.
3. Measure the voltage at the point between the LED and the transistor.
If the voltage is incorrect, replace the LED.
4. Replace the corresponding transistor.
LED Intensity Faulty If the intensity of the LEDs is faulty:
1. Send CCTM command 1001 0 1 to activate the LED of the
F1 key.
2. Send CCTM command 1002 3 to set the LED intensity level to high.
Figure 14.5 Circuit diagram of the function key LEDs and status LEDs
IND BRIGHT1
R601
FPGA
IND BRIGHT2
LED FUNC 1
LED FUNC 4
LED IND TX
LED IND RX
LED IND BUSY
3V3
R602
R603 R604
R34
0
D613
F1 Key
3V3
R605
R35
0
D614
F4 Key
Q604 Q605
3V3
R609
D615
Red
Q606
3V3
R612
R36
0
D616
Green
Q607
3V3
R616
D617
Amber
Q608
R34: 0Ω
R35: 0Ω
R36: 0Ω
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):
1.87V (on)
1.87V (on)
1.92V (on)
1.87V (on)
1.89V (on)
1.40V (off)
1.40V (off)
1.57V (off)
1.40V (off)
1.48V (off)

Tait TM8115 Specifications

General

Brand	Tait
Model	TM8115
Category	Radio
Language	English