Instruments And Conventions For Performing Diagnosis And Repair, Assembling/Disassembling Instructions - Selco Genesis 1100 Repair Manual

3) INSTRUMENTS AND CONVENTIONS FOR PERFOR-
MING DIAGNOSIS AND REPAIR, ASSEMBLING/DISAS-
SEMBLING INSTRUCTIONS
3.1) Instruments for basic diagnosis
The following are required:
- a multimeter with the following scales:
Ohm: from 0 to a few Mohm
Diode testing
Direct voltage (Vdc): from mVdc to 1000 Vdc
Alternating voltage (Vac): from 10 Vac to 700 Vac
NOTE: You are advised to use an instrument with
automatic scale since it is not theoretically possible to
predict the electrical quantity to be measured when
the machine has broken down.
- an AC/DC ammeter clamp at least in class 2.5 with e.o.s. 200A pk
- alternatively to the ammeter clamp, a shunt can be used with
value 60 mV @ 150 A.
NOTES:
* remember that other types of shunts can also be used,
but accuracy is reduced with higher capacities, whe-
reas with lower capacities the measurement must be
taken quickly to avoid overheating of the shunt
* once fitted, the shunt is at welding potential (be
careful especially with discharges during arc stri-
king in TIG HF with Genesis 1500 TLH!)
* the ammeter clamp is preferable as it is more practi-
cal
3.2) Repair tools
- complete set of fork spanners
- complete set of pipe spanners for hexagonal nuts
- complete set of blade screwdrivers
- complete set of Phillips screwdrivers
- complete set of Allen keys
- Phillips torque screwdriver for M3 screws with tigh-
tening torque adjustable range from 1 to 3 Nxm,
accuracy 0.1 Nxm
- crimper for insulated wire terminals (blue, red and
yellow)
- pliers for AMP contacts
- tweezers and cutting nippers - type commonly used
for electronic components
- tongs (dimensions suitable for closing gas pipe
clamps)
- welder for electronic components, minimum power
50 W
- portable electric drill

Instruments and conventions for performing diagnosis and repair, assembling/disassembling instructions

3.3) Conventions
By convention, when a measurement has to be taken between
two points, for example a
where to apply the red tip of the multimeter (a),while the black
tip is applied at the other end (b).
When a double arrow appears between two measuring points
(e.g.: c d ), the voltage to be measured is alternating
(normally at 50 Hz), therefore it does not matter in which order
the multimeter terminals are applied.
In drawings and tables, when a voltage measurement appears
referring to terminals of components such as DIODES, BJT,
MOSFET and IGBT, the multimeter is used in "diode test" mode
(these measurements are always taken with the machine swit-
ched off and normally give values in the range +0.10 ... +0.90
Vdc). In this case the following symbol is affixed beside the
value to be measured
Junction measurement (multimeter in "diode test" mode)
The following symbols will be used in the same way:
AC or DC voltage measurement (multimeter in voltmeter
mode)
Resistance measurement (multimeter in ohmmeter mode)
Current measurement (ammeter clamp or shunt + multi-
meter in millivoltmeter mode)
Frequency measurement (multimeter in frequency meter
mode)
The measuring conditions (power source on/off, MMA/TIG ope-
rating mode, etc.) are always clearly indicated beside the values
to be measured.
The connector terminals are indicated by the name of the con-
nector followed by a slash and the number of the terminal; for
example CN1/2 indicates terminal 2 of connector CN1.
Unless otherwise specified, all the measurements must be per-
formed with the boards fitted, together with their connections.
Remember that the first of the tests to be perfor-
med is the VISUAL CHECK!
The visual check reduces troubleshooting times
and directs any subsequent tests towards the
damaged part!
b , the arrow point indicates
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