RAT5 Manual version 1.2.0
RAT5 Information Manual version 1.2.0 © GW4GTE 2010
Page 22 of 29
6. Troubleshooting
If any problems are encountered the most likely cause will be a solder bridge somewhere on
the PCB.
6.1 Continuity checks
These should have been carried out during construction (section 3.1), but if in any doubt,
repeat as below
(__)
Carry out a careful visual inspection of the track using a magnifying aid.
(__)
Remove all ICs and carry out a resistance test from each IC pin to the
adjacent ones. There should be no short circuits detected except U2 pins 6
and 7. The only low resistance should be between U1 pins 11 to 12, reading
through L1 and R3 (typical reading: 23 ohms)
(__)
Carry out a resistance test from each IC pin to earth. The only pins that
should be directly connected to 0 V are: U1/2, U1/16, U2/4, and U3/4.
U2/3 and U3/3 will read to earth via RV2 and RV3 sliders respectively when
the controls are fully CCW – vary the controls to confirm.
If all continuity checks read ok, insert all Ics and proceed to 6.2 below.
6.2 Voltage checks
Test conditions:
Supply Voltage: 12V, Antenna input: open circuit
,
Controls
: All fully CCW (NC = pin not connected)
U1 pin number
Typical Voltage
U1 pin number
Typical Voltage
1
11.43
9
0.02
2
0
10
7.25
3
2.12
11
10.19
4
2.14
12
10.19
5
2.12
13
11.43
6
0.24
14
2.65
7
0.24
15
2.65
8
0.5
16
0
U2 pin number
Typical Voltage
U3 pin number
Typical Voltage
1
0.03 *
1
1.34 NC
2
0.02
2
0.09
3
0 *
3
0
4
0
4
0
5
6
5
5.69
6
5.92
6
12
7
5.92
7
6.08 NC
8
12
8
1.36
* With RV2 squelch fully CW readings are: U2/1 = 10.59V, U2/3 = 3.73V
If your RAT5 passes all the above tests and a fault still persists please do not hesitate to
contact the authors for further assistance. 100% support is available, and each kit includes a
free-repair service on kits returned as faulty on first-build.
