FAULT FINDING, REPAIR
AND MEASUREMENT
Test Project Document
LKS_2017_TP16_FFRM_ENSubmitted by:
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 2
1. INTRODUCTION TO TEST PROJECT DOCUMENTATION
1. Introduction To Test Project Documentation ... 2
2. Contents ... 3
3. Introduction ... 4
4. Description Of Project & Task... 5
5. Instruction To The Competitors ... 6
6. Equipment, Machinery, Installations And Materials Required ... 10
7. Marking Scheme ... 19
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 3
2. CONTENTS
This Test Project proposal consists of the following documentation/files: a. LKS_2017_XXI_TP16_FFRM_EN.docx
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 4
3. INTRODUCTION
This Test Project is a Stereo Multiplex (MPX) and FM Transmitter test, Instead of using special purpose ICs to produce the waveforms this design uses ordinary HCMOS logic. Audio Frequency (AF) signals are produced using binary counters and combinational logic and then filtered to obtain two very low distortion sine waves to serve as the test tones. These audio signals are then multiplexed by a 38 KHz Sub-Carrier to form a Left+Right and a Left-Right Double Side-Band Suppressed Carrier (DSBSC) signal to form the Stereo Multiplex (MPX). No fault and no measurement in the oscillator FM/ Modulation FM Block.
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 5
4. DESCRIPTION OF PROJECT & TASK
The block diagram of the Stereo Multiplex (MPX) and FM Transmitter is shown in Fig. 2.
Fig. 2 Block Diagram of Stereo Multiplex (MPX) and FM Transmitter test
Fig. 3: Audio Signals, Sub-Carrier and Multiplexed (MPX) Signals
The Signal Generator generates the 38 KHz sub-carrier and 19 KHz pilot tone. It uses an ingenious technique to generate 2 sine waves (audio) with very low distortion at around 300 Hz and 1.2 KHz.
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 6
(Fig 4). The audio signals being encoded as Left or Right is based on the phase of the sub-carrier.
The 16 different waveforms
300 Hz right/ 1.2 KHz left MPX no 19 KHz pilot 300 Hz right/ 1.2 KHz left MPX with 19 KHz pilot 1.2 KHz left only MPX no 19 KHz pilot
1.2 KHz left only MPX with 19 KHz pilot 300 Hz left only MPX no 19 KHz pilot 300 Hz left only MPX with 19 KHz pilot 300 Hz left/1.2 KHZ right MPX no 19 KHz pilot 300 Hz left/1.2 KHZ right MPX with 19 KHz pilot 1.2 KHz right only MPX no 19 KHz pilot
1.2 KHz right only MPX with 19 KHz pilot 300 Hz right only MPX no 19 KHz pilot 300 Hz right only MPX with 19 KHz pilot 300 Hz + 1.2 KHz mono audio only 1.2 KHz mono audio only
300 Hz mono audio only 19 KHz pilot only
Fig. 4. The 16 different waveforms
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 7
6. INSTRUCTION TO THE COMPETITORS
Fault Finding and Repair
1. Supply voltage of 12 + 0.1 volts to be applied to terminal P1, please take note of the polarity.
2. Adjust R5 to set the frequency 153 KHz + 0.5 KHz of the clock output at U7_3. If competitor board doesn’t match with the frequency, competitor can exchange the board to jury.
3. There are 3 faults which do not correspond to the demand specifications. Find and repair it.
4. Describe Defective Part and Fault Symbol.
5. When you request repair parts, both of the Competitor and the Jury have to sign to part list.
6. Describe the evidence of the repair.
FAULT
SYMBOL
DESCRIPTION FAULT
SYMBOL
DESCRIPTION
Open
(part, wire or PCB trace)
Stuck at high voltage (Pin, input, output, etc.)
Short
(part, wire or PCB trace)
Stuck at low voltage (Pin, input, output, etc.)
Part with larger value
(resistor, capacitor, etc.)
?
Incorrect part number or wiring connecting
Part with smaller value
(Resistor, capacitor, etc.)
+/-
Wrong Polarity
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 8
You may use the following Labels:
LOCATION CATEGORY SAMPLE
Power +5V/+12V/-5V/+5V/GND
Pin of IC IC2_8
Component of R/C/L R7_1㸦left/up:1 right/down:2㸧
Test Point TP1
Between Two Components R1-R2
Fig.6 Location Symbols Table
DEFECTIVE PART FAULT SYMBOL
Fault #1 IC2_8 - R7_1
BEFORE AFTER
Measurement #1
Node: _ R7_1______
Fig.7 Example of description of answer script (Condition: the frequency of the oscillator is too high.)
Voltage at R7_ 1 below
than 1V
Voltage at R7_ 1
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 9
DEFECTIVE PART FAULT SYMBOL
Fault #2 R1
Fig.8 Example of description of answer script (Condition: the frequency of the oscillator is too high.)
GND GND
2ms 4ms
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 10
7. MEASUREMENT
Measure the following items:
1. Measure and record the frequency at U19_1
2. Press S1 button until signal out U10_12 = LOW, U10_9 = HIGH, U10_8 = HIGH, U10_11 = LOW, then measurement MPX OUT signal at P4.
3. ... 4. ...
For each measurement, sketch a schematic showing how to measure, using following equipment symbols.
EQUIPMENT SYMBOL
Power Supply
Voltmeter
Ammeter
Oscilloscope
Function Generator
GND
Fig.9 Equipment Symbol Table
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 11
8. EQUIPMENT, MACHINERY, INSTALLATIONS AND MATERIALS REQUIRED ITEM QTY MATERIAL DESCRIPTION NOTES
1 1 FFRM PCB Material for the
project
12
9. PCB AND SCHEMATIC
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 19
10. MARKING SCHEME
MAX MARK ASPECT OF CRITERION - DESCRIPTION
12 Finding faulty spots and evidence 3 Repairing (IPC-A-610-D)
8 Validity of measuring results
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 20
11. OTHERS
1. Part List for repairing
2. Fault Finding and Repair – Answer Script 3. Measurement – Answer Script
Part list for repairing
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 21
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 22
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 23
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 24
Fault Finding & Repair – Answer Script
DEFECTIVE PART FAULT SYMBOL
Fault #1
BEFORE AFTER
Measurement #1
Node: _______
DEFECTIVE PART FAULT SYMBOL
Fault #2
BEFORE AFTER
Measurement #2
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 25
DEFECTIVE PART FAULT SYMBOL
Fault #3
BEFORE AFTER
Measurement #3
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 26
Measurement – Answer Script Measurement #1
Measurement SCHEMATIC
Measurement Output
Vertical Settings:
/div
Horizontal Settings:
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 27
Verification output graph
Calculation Volt peak to peak with formula Calculation frequency with formula
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 28
Measurement #2
Measurement SCHEMATIC
Measurement Output
Vertical Settings:
/div
Horizontal Settings:
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 29
Verification output graph
Calculation Volt peak to peak with formula
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 30
Measurement #3
Measurement SCHEMATIC
Measurement Output
Vertical Settings:
/div
Horizontal Settings:
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 31
Verification output graph
Calculation Volt peak to peak with formula
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 32
Measurement #4
Measurement SCHEMATIC
Measurement Output
Vertical Settings:
/div
Horizontal Settings:
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 33
Verification output graph
Calculation Volt peak to peak with formula Calculation frequency with formula
Test Project proposal for skills competition LKS_2017_XXV_TP16_FFRM_EN
Version: 1.0
Date: 20.10.2016 34
