Trouble shooting.
999 out of a 1000 times, the reason a newly built kit doesn't work right away is due to assembly errors. Parts can be damaged due to
handling and some of the semi-conductors can be susceptible to ESD (Electric Static Discharge), but this is rare. Therefore, a close visual
inspection will often be all you need to find the problem.
Look for:
●
Bad soldering – missing connections and solder shorts. Bad connections to the magnet wire on the coils is a common problem.
Check for continuity.
●
Miss placed parts – IC's in the wrong socket or facing the wrong way, transistors in the place and so on.
●
It can be sometimes difficult to read the number on the little multilayer ceramic caps and therefore easy to get them in the wrong
place. Having a 0.1 ufd by-pass cap where a picofarad part should be and visa-versa will definitely cause something not to work.
If something doesn't pop right out at you, some actual trouble shooting to identify the problem area is required. Knowing where to look for a
problem is half the battle. For this you need to do a process of elimination. Finding out what does work can lead to finding what doesn't work
and then to the solution. For this some test equipment is needed. A voltmeter is need to start and having an Oscilloscope with which to trace
and measure the RF signals is a big plus. Most of you will likely only have the voltmeter to use. The voltage tables below can help locate a
problem area. Voltages can vary by 10% due to variations in voltmeters and the actual 5V regulator voltage. Some of the transistors will have
RF signals on them which can affect the DC voltage reading depending on how your voltmeter reacts to the RF signal. You only have to
worry if voltages aren't even close.
Voltages measured with 13.8V DC supply connected.
SurvivorB1_20171113
17
U1, U2 SA 612
Pin Voltage
Pin voltage
1
1.38
8
5.00
2
1.38
7
4.16
3
0
6
4.93
4
3.84
5
3.84
U5 TINY13A
Pin Voltage
Pin voltage
Rx /
Tx
1
4 /
0
8
5.00
2
5 /
0
7
0 /
0
3
0 or 5
6
0 /
5
4
0.00
5
5 /
0
U6 LM358
Pin Voltage
Pin voltage
1
2.50
8
5.00
2
2.50
7
2.50
3
2.50
6
2.50
4
0.0
5
2.50
U7 LM386
Pin Voltage
Pin voltage
1
1.40
8
1.40
2
0.0
7
6.6
3
0.0
6
13.5
4
0.0
5
6.5
U4 74HC4053
Pin Voltage
Pin
Voltage
1
4.93
16
5.0
2
4.93
15
4.93
3
4.93
14
2.5
4
4.93
13
2.5
5
4.93
12
0
6
0.0
11
4.0 /
0
7
0.0
10
4.96 /
0
8
0.0
9
4.96 /
0
RED
= Tx mode voltages
E (S)
B (G)
C (D)
Q1
1N50CTA 0 /
0
13.4
/ 0
0 /
0
Q2
2N3904
0 /
0.75
0 /
1.4
13.5 /
13.5
Q3
2N3906
13.5 /
13.5
13.4 /
12.7
0 /
13.4
Q4
2N7000
0 /
0
0 /
13.5
13.5 /
0
Q5
2N3904
0 /
2.1
0 /
2.8
0 /
10.3
Q6
2N7000
0 /
0
0 /
5
13.4 /
0
Q7
2N3904
0 /
0
0 /
0.7
0 /
0
Q8
2N3904
3.1 /
3.1
3.8 /
3.8
5 /
5
Q9
2N3904
0 /
1.65
0 /
2.25
0 /
5.1
Q10 2N7000
0 /
0
5 /
0
0 /
1.9
Q11
2N7000
0 /
0
0 /
0
0 /
0.75
Q12 2N3819
3.6 /
3.6
0 /
0
5 /
5
Q13 J-176
0 /
0
5 /
5
0 /
0
Q14 2N3904
2.0
2.6
4.4
Q15 2N3819
0.9 /
0.9
-0.7 /
-0.7
4.8 /
4.8
Q16 2N3904
2.6 /
2.6
3.2 /
3.2
4.4 /
4.4
Q17 2N3904
0 /
0
0 /
0
5 /
5
Q18 IFR510B
0 /
0
0 /
~2.5
13.5 /
13.5
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