a full report on the summer internship project which i did in LG Electronics vendor name E- Durables, report consist of all assembling process of microwave and PCB.

1. 1
SUMMER TRAINING REPORT
On
ASSEMBLING OF MICRO OVEN AND PCB(PRINTED CIRCUIT BOARD)
IN
PARTIAL FULFILLMENT OF GRADUATION DEGREE OF
B.TECH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
Submitted To
Mr. SANJAY SINGH
PROJECT CO-ORDINATOR
ECE, UIT
BY
MUSTAHID ALI
Roll No: 08300102033
B.TECH (ECE)
UTTARANCHAL INSTITUTE OF TECHNOLOGY
DEHRADUN .

2. 2
DECLARATION
I, MUSTAHID ALI, Enrollment No: 08300102033, a student of B.TECH
(Electronics And Communication Engineering), batch 2008-12, Uttaranchal Institute Of
Technology, Dehradun, hereby declare that the work presented in this project report
titled “Assembling Of Micro Oven And PCB (Printed Circuit Board)” submitted in
partial fulfillment of requirement of the award of degree of B.tech(ECE) is an authentic
record of my original work. The matter embodied in this project has not been printed,
published or submitted elsewhere in any form for the award of any other degree.
(Mustahid Ali)
B.TECH (Electronics And Communication Engineering)
Roll No. 08300102033
Uttaranchal Institute Of Technology,
Dehradun

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CERTIFICATE
This is to certify that Mr. MUSTAHID ALI, student of B.TECH (Electronics And
Communication Engineering)), Batch 2008-12, Uttaranchal Institute Of Technology,,
Dehradun has carried out the project titled “Assembling Of Micro Oven And PCB
(Printed Circuit Board)” under my supervision and guidance. The project embodies
the results of original work and studies carried out by the student himself.
Date:
Place: Selaqui, Dehradun
Mr. VINEET CHOUDARY
Traning co-ordinator,
E-DURABLES ‖.

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ACKNOWLEDGEMENT
The project title “Assembling Of Micro Oven And PCB (Printed Circuit Board)” has
been completed by me during 15th June to 30th July 2010 at E-DURABLES ‖.
. I have completed this project carried out under the guidance of Mr. Vineet Kumar
I am intellectually debated towards my guide Mr. Vineet Kumar, who has augmented my
knowledge in the field of Computer Science. He has helped me learn about the
processes followed in the working of an industry and has helped me gain an insight into
the Electronics Sector.
My increased spectrum of knowledge in this field is the result of their constant
supervision and direction that has helped me to absorb relevant and high quality
information.
Last but not the least, I feel indebted to all those persons and organization who have
provided help directly or indirectly in successful completion of this study.
30th July 2011
MUSTAHID ALI
B.TECH
(Electronics And Communication)
08300102033

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TABLE OF CONTENTS
Declaration…………………………………………………………………………………………………………….……………...I
Project Completion Certificate ………………………………………………………………………………………….....II
Faculty Guide
Certificate……………………………………………………………………………………………………........................III
Acknowledgement……………………………………………………………………………………………………………..IV
Chapter 1 Introduction ……………………………………………………….
Chapter 2 Microwave Oven Contents………………………………….
1. Basic Design ……………………….
2. RAW MATERIAL……………………………
3. Manufacturing Process………………………………
4. Oven Cavity And Door Manufacture……………………….
5. Magnetron………………………………
6. The Magnetron Tube Assembly……………………………….
7. Main Chassis Assembly………………………………………….
8. Stirrer Fan…………………………….
9. Control Switches, Relays And Motors…………………………………….
10. Front Panel……………………..
11. Control Panel………………………
12.Testing And Packageing The Oven…………………………..
13. Quality Control………………………………………

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14. Faults………………………..
15. testing(various components)…………………………
16. Specification………………………………..
17. Troubleshooting…………………..
PCB(PRINTED CIRCUIT BOARD)…………………………….
1.Steps Of Assembling Of PCB For Halonix 8 watt CFL…………………………
The Future………………………………………….

7. 7
CHAPTER 1
INTRODUCTION
Microwaves are actually a segment of the electromagnetic wave spectrum, which comprises
forms of energy that move through space, generated by the interaction of electric and magnetic
fields. The spectrum is commonly broken into subgroups determined by the different
wavelengths (or frequencies) and emission, transmission, and absorption behaviors of various
types of waves. From longest to shortest wavelengths, the spectrum includes electric and
radio waves, microwaves, infrared (heat) radiation, visible light, ultraviolet radiation, X-
rays, gamma rays, and electromagnetic cosmic rays. Microwaves have frequencies
between approximately .11 and 1.2 inches (0.3 and 30 centimeters).
Microwaves themselves are used in many different applications such as
telecommunication products, radar detectors, wood curing and drying, and medical
treatment of certain diseases. However, certain of their properties render them ideal for
cooking, by far the most common use of microwave energy. Microwaves can pass
through plastic, glass, and paper materials; metal surfaces reflect them, and foods
(especially liquids) absorb them. A meal placed in a conventional oven is heated from
the outside in, as it slowly absorbs the surrounding air that the oven has warmed.
Microwaves, on the other hand, heat food much more quickly because they penetrate
all layers simultaneously. Inside a piece of food or a container filled with liquid, the
microwaves agitate molecules, thereby heating the substance.
The ability of microwave energy to cook food was discovered in the 1940s by Dr. Percy
Spencer, who had conducted research on radar vacuum tubes for the military during
World War II. Spencer's experiments revealed that, when confined to a metal enclosure,
high-frequency radio waves penetrate and excite certain type of molecules, such as
those found in food. Just powerful enough to cook the food, the microwaves are not
strong enough to alter its molecular or genetic structure or to make it radioactive.

8. 8
Raytheon, the company for which Dr. Spencer was conducting this research, patented
the technology and soon developed microwave ovens capable of cooking large
quantities of food. Because manufacturing costs rendered them too expensive for most
consumers, these early ovens were used primarily by hospitals and hotels that could
more easily afford the $3,000 investment they represented. By the late 1970s, however,
many companies had developed microwave ovens for home use, and the cost had
begun to come down. Today, microwaves are a standard household appliance,
available in a broad range of designs and with a host of convenient features: rotating
plates for more consistent cooking; digital timers; autoprogramming capabilities; and
adjustable levels of cooking power that enable defrosting, browning, and warming,
among other functions.

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CHAPTER 2
MICROWAVE OVEN CONTENTS
Basic Design
The basic design of a microwave oven is simple, and most operate in essentially the same
manner. The oven's various electronic motors, relays, and control circuits are located on the
exterior casing, to which the oven cavity is bolted. A front panel allows the user to program the
microwave, and the
The oven cavity and door are made using metal-forming techniques and then painted using
electro-deposition, in which electric current is used to apply the paint.
The magnetron tube subassembly includes several important parts. A powerful magnet is placed
around the anode to provide the magnetic field in which the microwaves will be generated, while
a thermal protector is mounted directly on the magnetron to prevent damage to the tube from
overheating. An antenna enclosed in a glass tube is mounted on top of the anode, and the air
within the tube is pumped out to create a vacuum. Also, a blower motor used to cool the metal
fins of the magnetron is attached directly to the tube.
door frame has a small window to enable the cook to view the food while it is cooking.
Near the top of the steel oven cavity is a magnetron—an electronic tube that produces high-
frequency microwave oscillations—which generates the microwaves. The microwaves are
funneled through a metal waveguide and into a stirrer fan, also positioned near the top of the
cavity. The fan distributes the microwaves evenly within the oven. Manufacturers vary the
means by which they disburse microwaves to achieve uniform cooking patterns: some use dual
stirrer fans located on opposite walls to direct microwaves to the cavity, while others use entry
ports at the bottom of the cavity, allowing microwaves to enter from both the top and bottom. In
addition, many ovens rotate food on a turntable.

10. 10
Raw Materials
The cover or outer case of the microwave oven is usually a one-piece, wrap-around
metal enclosure. The oven's inside panels and doors are made of galvanized
or stainless steel and are given a coating of acrylic enamel, usually light in color to
offer good visibility. The cooking surface is generally made of ceramic or glass.
Inside the oven, electromechanical components and controls consist of timer motors,
switches, and relays. Also inside the oven are the magnetron tube, the waveguide, and
the stirrer fan, all made of metal. The hardware that links the various components
consists of a variety of metal and plastic parts such as gears, pulleys, belts, nuts,
screws, washers, and cables.

11. 11
The Manufacturing
Process
Oven cavity and door manufacture
 1 The process of manufacturing a microwave oven starts with the cavity and the door.
First, the frame is formed using automatic metal-forming presses that make about 12 to
15 parts per minute. The frame is then rinsed in alkaline cleaner to get rid of any dirt or
oil and further rinsed with water to get rid of the alkaline solution.
 2 Next, each part is treated with zinc phosphate, which prepares it for electro-deposition.
Electro-deposition consists of immersing the parts in a painttank at 200 volts for 2.5
minutes. The resulting coating is about 1.5 mils thick. The parts are then moved through a
paint bake operation where the paint is cured at 300 degrees Fahrenheit (149 degrees
Celsius) for 20 minutes.

12. 12
The chassis or frame is mounted in a pallet for the main assembly operation. A pallet is a
vise-like device used in conjunction with other tools.
 3 After the door has been painted, a perforated metal plate is attached to its window
aperture. The plate reflects microwaves but allows light to enter the cavity (the door will
not be attached to the cavity until later, when the chassis is assembled).
MAGNETRON
The magnetron is the heart of a microwave oven. It is much like a radio transmitter in that it
produces RF energy and radiates the energy into the cooking cavity where it is absorbed by the
food. The magnetron uses permanent magnets and a half-wave voltage doubler circuit (the HV
capacitor and HV diode) to oscillate and produce the 2450 Mhz cooking frequency, thus
converting the 60 Hz supply voltage into microwave energy

13. 13
The magnetron tube subassembly
 4 The magnetron tube assembly consists of a cathode cylinder, a filament heater, a metal
anode, and an antenna. The filament is attached to the cathode, and the cathode is
enclosed in the anode cylinder; this cell will provide the electricity that will help to
generate the microwaves. Metal cooling fins are welded to the anode cylinder, and a
powerful magnet is placed around the anode to provide the magnetic field in which the
microwaves will be generated. A metal strap holds the complete assembly together. A
thermal protector is mounted directly on the magnetron to prevent damage to the tube
from overheating.
 5 An antenna enclosed in a glass tube is mounted on top of the anode, and the air within
the tube is pumped out to create a vacuum. The waveguide is connected to the magnetron
on top of the protruding antenna, while a blower motor used to cool the metal fins of the
magnetron is attached directly to the tube. Finally, a plastic fan is attached to the motor,
where it will draw air from outside the oven and direct it towards the vanes. This
completes the magnetron subassembly.

14. 14
Main chassis assembly
 6 The chassis assembly work is performed on a pallet—a work-holding device used in
conjunction with other tools—located at the station. First, the main chassis is placed on
the pallet, and the cavity is screwed on to the chassis. Next, the door is attached to the
cavity and chassis by means of hinges. The magnetron tube is then bolted to the side of
the cavity and the main chassis.
In a completed microwave oven, the magnetron tube creates the microwaves, and the
waveguide directs them to the stirrer fan. In turn, this fan points the waves into the oven
cavity where they heat the food inside.
 7 The circuit that produces the voltage required to operate the magnetron tube consists of
a large transformer, an oil-based capacitor, and a high voltage rectifier. All of these
components are mounted directly on the chassis, close to the magnetron tube.
Stirrer fan
 8 The stirrer fan used to circulate the microwaves is mounted on top of the cavity. Some
manufacturers use a pulley to drive the fan from the magnetron blower motor; others use
a separate stirrer motor attached directly to the fan. Once the stirrer fan is attached, a
stirrer shield is screwed on top of the fan assembly. The shield prevents dirt and grease
from entering the waveguide, where they could produce arcing and damage the
magnetron.

15. 15
Control switches, relays, and motors
 9 The cook switch provides power to the transformer by energizing a relay and a timer.
The relay is mounted close to the power transformer, while the timer is mounted on the
control board. The defrost switch works like the cook switch, activating a motor and
timer to operate the defrost cycle. Also mounted on the control board are a timer bell that
rings when the cooking cycle is complete and a light switch that allows viewing of the
cavity. A number of interlocking switches are mounted near the top and bottom of the
door area. The interlocking switches are sometimes grouped together with a safety switch
that monitors the other switches and provides protection if the door accidently opens
during oven operation.
Front panel
 10 A front panel that allows the operator to select the various settings and features
available for cooking is attached to the chassis. Behind the front panel, the control circuit
board is attached. The board, which controls the various programmed operations in their
proper sequence when the switches are pushed on the front panel, is connected to the
various components and the front panel by means of plug-in sockets and cables.

16. 16

17. 17
Making and assembling the case
 11 The outer case of the microwave is made of metal and is assembled on a roll former.
The case is slipped onto the preassembled microwave oven and bolted to the main
chassis.
Testing and packaging the oven
 12 The power cords and dial knobs are now attached to the oven, and it is sent for
automatic testing. Most manufacturers run the oven from 50-100 hours continuously as
part of the testing process. After testing is complete, a palletizer robot records the model
and serial data of the oven for inventory purposes, and the oven is sent for packaging.
This completes the manufacturing process.
QUALITY CONTROL
Extensive quality control during the manufacture of microwave ovens is essential, because
microwave ovens emit radiation that can burn anyone exposed at high levels for prolonged
periods. Federal regulations, applied to all ovens made after October 1971, limit the amount of
radiation that can leak from an oven to 5 milliwatts of radiation per square centimeter at
approximately 2 inches from the oven surface. The regulations also require all ovens to have two
independent, interlocking switches to stop the production of microwaves the moment the latch is
released or the door is opened.
In addition, a computer controlled scanner is used to measure emission leaks around the door,
window, and back of the oven. Other scanners check the seating of the magnetron tube and
antenna radiation. Each scanner operation relays data to the next-on-line operation so that any
problems can be corrected.

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QUALITY CONTROL SERIAL
IQC(incoming quality control)
LQC( line quality control)
FQC( final quality control)
ELT(early life testing)
OQC(out going quality control )
IQC(incoming quality control)
In this the quality of the import material is checkout by using various machines and visually.
The incoming material checkout by taking the 20 samples out of 100 .
LQC( line quality control)
In line quality control the manufacturing product is checked by using various machines and other
electronics equipment.
FQC( final quality control)
After manufacturing a complete product the FQC will be done , in this the final quality of the
product is checked , the outer parts will be taken in considered , is that there will be no dent,
mark, and scratches on the body of product. If there will be any one of them the product will be
sent back for repairing again.
ELT(early life testing)
ELT is early life time testing , the microwave will be tested for atleast for 14 hours . Different
microwave oven have different steps and different time of early life testing.

19. 19
FIG 1.

20. 20
FIG 2.

21. 21
FIG 3.

22. 22
FIG 4
. OQC(out going quality control )
The packing of the product is considered in this quality control.
FAULTS
 The cavity dent and cavity point stressed.
 Micro mode , no power consumption.
 TT motor not work properly.
 Suction fan not work properly.
 Base plate may be rusty and dusty.
 H.V fails.
 Grill mode no power consumption.
 Convention mode no power consumption.

23. 23
 Chamber fan may not work properly and it may touch the other part of the
oven.
 Door melting problem or door latching.
 Door high leakage .
 Cavity high leakage.
 Magnetron leakage.
 PCB problem.
 Wrong wireing.
THE TORQUE IN THE SYSTEM
The unit of the torque is newton metre or kgfcm.
The requirement of the torque for different part of the microwave is given
as
 Megnetron 16- 26 Nm.
 High voltage transformer 20 -30 Nm.
 Latching 25-35 Nm.
 Cavity 16-26 Nm.
The requirement of voltage for HVT is 1.4 kv and internal
resistance is 20 MΩ.
The microwave leak detector should be 2.8w/cm 2
without
case and it should be 8.8 w/ cm2
.
The current in microwave is +- 4.9 A with 10% tolerance.
 The power consumption in microwave is 1.2 kw with 10%
tolerance.

24. 24
TESTING.
Testing the magnetron
WARNING: First, with power disconnected, discharge the high voltage capacitor.
See the section "Safe discharging of the high voltage capacitor".
* A magnetron with an open filament will result in no heat but no other
symptoms. The bad connection may be internal (in which case the magnetron
will need to be replaced) or external at the filament terminals (which may
be repairable).
* A magnetron with with a short between the filament/cathode and anode will
likely result in a loud hum from the HV transformer and/or magnetron when
the cook cycle is initiated but the main fuse will probably not blow.
* A magnetron with other faults may result in a variety of symptoms including
erratic or low output power or intermittent operation. See the section:
"Comprehensive list of magnetron failure modes".
There is no totally definitive way to determine if a magnetron is good without
actually powering it under operating conditions but the following tests will
catch most problems:
* Magnetron filament. The resistance should be infinite from the filament
connections to the case and a fraction of an ohm between the filament
terminals with the wiring disconnected from the magnetron.
While measuring resistance from filament chassis, gently tap the magnetron
to determine if there is an intermittent short. However, such problems may
only show up once the filament heats up and parts expand.
It may be possible to determine if the magnetron filament is actually
working by connecting just the filament connections to a low voltage
high current supply on a Variac (e.g., a microwave oven transformer but just
the filament connections). The ceramic insulators are translucent and should
show a glow with a working filament. The one at the antenna may be visible
if the magnetron is removed from the oven or with a dental mirror looking
into the waveguide. WARNING: Make sure you ONLY have the filament connected!
* Evidence of arcing (visible blackening around ventilation holes in base or
burnt odor) usually indicates a bad magnetron.
* Melting or other damage to the antenna cover ('bull-nose' or 'bullet') may

25. 25
be the result of arcing due to problems in the oven cavity or waveguide
(perhaps operating with nothing in the oven) or a defective magnetron.
(This part is only visible with the magnetron removed from the oven). If
a problem elsewhere has been corrected, the damaged antenna cover can be
pulled off and replaced from a magnetron that died of other causes - try
your local appliance repair shop. (The shape doesn't matter as long as
it fits tightly - there are several diameters, however.) Your magnetron
may still be good.
Most common magnetron failure modes:
* Filament could be shorted to case - check with ohmmeter. Anything less than
infinity means the tube is bad though it could be charring due to arcing
outside the vacuum in the box with the filament connections. Tap the tube
while measuring to check for intermittents.
* Filament could be shorted to itself - tough to test since it is such a low
resistance to start. Compare with good magnetron. (Yeh, right. If you had
one, this wouldn't be an issue!) Tap the tube while measuring to check for
intermittents. This fault isn't really likely.
* Filament could be open - check with ohmmeter. Tap the tube while measuring
to check for intermittents. However, loose filament connectors (Fast-Ons)
are more likely than a broken filament. Therefore, check directly at the
magnetron terminals with both lugs pulled off.
* Magnetron could be gassy (or up to air) and arcover internally once power is
applied. The filament could expand, shift position, and short once heated.
There is no easy way to test for these possibilities other than substituting
a known good magnetron.
* Internal or external arcing resulting in physical damage. External arcing
could be at the antenna or inside the filament box. Internal arcing will
not leave any visible evidence but the damage will result in the magnetron
failing totally or running with reduced output.
* Overheating might result from a broken or cracked magnet (reduced magentic
field) or other internal problems. While there may be some output power,
the thermal protector will shut down the oven prematurely.

26. 26
Comprehensive list of magnetron failure modes
Here is a list of typical magnetron failure modes. The percentage of each type
of failure varies. Currently, internal shorts and loose filament connectors
are probably at the top of the list. An internal plate-cathode short may only
manifest itself under the stress of high voltage during operation.
1. Shorts. (a) Internal plate-cathode/filament short or (b) Internal arcing.
Symptoms: No heat, loud hum when entering cook cycle, possible blown HV
fuse (but will not likely blow the main fuse).
In ovens equipped with fuses that monitor the high voltage system, such
as some commercial Sharp models and most commercial and domestic Amana
models, the high voltage fuse would probably blow. But, rarely will a
shorted magnetron cause the main line fuse to blow. (I suppose the
transformer absorbs most of the current surge.) In fact, with reference
to the other symptoms below, there are almost no failures where the
magnetron causes the line fuse to blow.
2. Loose filament connectors (these may be repairable). There will often
also be visual symptoms at the magnetron: Signs of overheating, such as
discoloration; and evidence of carbon tracks or pits on magnetron terminals
when the connectors are removed. An intermittent filament (internal) is
also possible (but not repairable).
Symptoms: No heat or erratic heat.
The slip-on connectors can loosen, overheat, build up resistance and
eventually loose contact. If the the magnetron terminal(s) have not been
burned too severely, the connection(s) can usually be repaired. We prefer
cleaning up the terminal, then soldering the filament wires directly to
the terminal.
Note: when discharging HV capacitor, since there is no load, it may end
up being charged to a much higher voltage than is normal. Be prepared
for a larger spark if you use a screwdriver to discharge it!
3. Open filament.
Symptoms: No heat.
See note about HV capacitor in (2) above.

27. 27
4. In the older glass-dome models, the vacuum envelope can rupture.
Symptoms: No heat, loud buzz due to arcing when entering cook cycle,
possible blown HV fuse.
See comments about fuses in (1) above.
5. Filament breakdown. Usually occurs after a few minutes of normal operation,
possible blown HV fuse.
Symptoms: No heat, loud hum once it occurs.
See comments about fuses in (1) above.
6. Low output. Occurs as cathode emission decreases from long use.
Symptoms: Reduced cooking power.
7. Moding. Occurs when magnetron oscillates in one or more undesirable
frequencies.
Symptoms: (a) Reduced or no cooking power, (b) RF interference. However,
some food products (with high water content) may cook normally, whereas
the result with other foods is very unsatisfactory. RF interference is
possible but usually only occurs if there is actual structural damage to
either the magnetron, its RF gasket or waveguide flange, or its RF
(feed-through) capacitors.
8. Off frequency. Physical characteristics can change and cause magnetron to
oscillate at frequencies slightly higher or lower than 2.45 GHz.
Same as (7a) above.
9. RF leakage. Structural failure can cause leakage from magnetron housing.
Symptoms: Microwave leakage into electronics bay, erratic control panel
behavior. It can be very frustrating because the symptoms disappear when
the oven's outer cover is removed. With the cover in place, the escaping
RF energy is confined, and eventually builds up around the control panel
circuitry causing unusual symptoms.
10. Insulation breakdown of the internal leads or at magnetron insulators
or antenna terminal.
Symptoms: Arcing, burning smell from magnetron, loud hum, no heat.
11. Cracked magnet(s).
Symptoms: Reduced or no cooking power, magnetron overheating, occasional
'snapping' sound.

28. 28
Testing the high voltage transformer
WARNING: First, with power disconnected, discharge the high voltage capacitor.
See the section "Safe discharging of the high voltage capacitor".
* A shorted winding or short between a winding and the core/chassis in the HV
transformer may result in a blown fuse, loud hum, overheating, audible
arcing, a burnt aroma, or simply no heat.
* An open winding will likely result in no heat but no other symptoms.
Disconnect terminals as required to make the following tests:
* The resistances of the primary should be .1 to .5 ohms (.2 ohms typical).
* The resistance of the filament winding will likely be so low as not to be
detectable with your multimeter. The only measurement easily made would
be that there is no short to the chassis.
* Typical resistance readings for the transformer HV secondary are in the 25
to 150 ohms range (depending on the power rating of the oven) from HV
connection to chassis. A typical midsize might be 65 ohms. An open would
be an obvious failure. However, based on the way these are wound, a
winding-to-winding short would not cause enough of a resistance change to
be detected with an ohmmeter unless you could compare with an identical
model transformer from the same lot number.
Testing the high voltage transformer more fully is difficult without fancy
equipment. Only major short circuits can be identified in the transformer
with an ohmmeter since the nominal resistance of the windings is unknown.
However, open windings (not very likely) can be located and other faults
can be identified by the process of elimination.
Note: in the discussion below, it is assumed that the fuse is blowing due to
a possible short in the HV transformer. Alternatively, there may be a loud
hum as the HV transformer struggles due to a fault in the HV transformer or
a shorted HV diode, magnetron, or a short in the HV wiring. Also note that
depending on the severity of the fault, the fuse may not actually blow (at
least not immediately) but there will likely be a loud hum when the HV
transformer is powered.
* Disconnect the primary of the HV transformer and initiate a cook cycle. If
the fuse still blows, you have a problem elsewhere such as a defective
interlock or shorted wire.

29. 29
* Assuming the fuse does not blow, unplug the oven and reconnect the primary
of the HV transformer.
* If the other components - HV diode, HV capacitor, magnetron - test out,
remove the high voltage and filament connections to the transformer, power
up the oven, and initiate a cook cycle. If the fuse does not blow, the
transformer is likely good and there are still problems in the high voltage
components. Possibly something is failing only when full voltage is applied.
* If the fuse still blows, then the problem is likely with the triac (if used),
a shorted wire, or shorted transformer.
* If the fuse does not blow with the secondary isolated, reconnect only the
magnetron filament (not the HV) to the transformer and power it up again.
If the fuse now blows, then it is possible that the magnetron filament is
shorted.
* If your oven uses a triac, remove and bypass it. Now, if the fuse still
blows when the oven is plugged in (door closed to enable the interlocks),
the problem is likely with the transformer.
Unplug the oven, discharge the HV capacitor.
* Check for damaged wires that may be shorting to the chassis. Repair or
replace these as necessary.

30. 30
Testing and repairing the wiring and connections
WARNING: First, with power disconnected, discharge the high voltage capacitor.
See the section "Safe discharging of the high voltage capacitor".
Inspect the wiring - especially between the magnetron, HV transformer, and
other components of the high voltage circuits for signs of arcing and excessive
heating or burning. Arcing may be the result of the wire scraping against a
sharp sheet metal edge due to poor placement and or vibration. A bit of
electrical tape may be all that is needed.
Since the magnetron filament in particular uses high current, any resistance
at the press (Fast-On) connections will result in heating, weakening of the
lug, more heating, and eventual failure or erratic operation. Try to pull off
each of the lugs. They should not be loose - you should have to work at
removing them. However, note that some lugs are of the locking variety and
require that you push a little tab to release them.
Check for loose, burnt, or deteriorated lugs in the filament circuit (not just
the magnetron). If you find evidence of this:
* Remove the lugs and clean the terminals with fine sandpaper or a file. If
they are not too badly deteriorated, they will still work even if they are
somewhat ugly.
* If the lugs and their wire connections appear to be in good condition but
come off their terminals easily, try squeezing them a little tighter with a
pair of pliers and reinstall. Otherwise, cut off the old ones and replace
them.
* If any connections between the lug and the wire or HV diode are at all loose,
solder it with a high wattage soldering iron or soldering gun.
* Alternatively, use a drill to make a hole in each terminal, and then fasten
the (tinned) wire directly (or better yet) a new ring lug to the terminal
with a machine screw, nut, and lockwasher. Soldering is also possible.
These approaches will work as long as there is enough metal remaining for a
solid connection and may permit you to salvage a magnetron or HV transformer
that would otherwise need to be replaced.
Also check for bad solder connections between the terminals on the high voltage
transformer and the enameled wire used for its windings. If you find anything
suspect, scrape away the enamel and surface corrosion and resolder with a high
wattage soldering iron or soldering gun.

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Testing the high voltage components
WARNING: First, with power disconnected, discharge the high voltage capacitor.
See the section "Safe discharging of the high voltage capacitor".
Assuming the oven passes the above test for interlocks and door alignment, the
triac (if used) may be defective. There could also be a wire shorting to the
chassis. However, the most likely problems are in the microwave generator.
An ohmmeter can be safely used to quickly determine if the capacitor, HV diode,
or magnetron are a dead short (as well as for an open magnetron filament).
Use an ohmmeter to test the diode and capacitor. While connected in circuit,
the resistance in at least one direction should be several M ohms. (Try it in
both directions, use the higher reading). Test the magnetron from the filament
to chassis - it should be high in at least one direction. Test the filament
for continuity - the resistance of a good filament is close to 0 (less than 1
ohm).
Where the capacitor and diode are combined into one unit, it should be possible
to test each component individually and replace only the one that is found to
be defective if the entire assembly is excessively expensive or not available.
These may be considered to fail/no conclusion tests - they can definitively
identify parts that are bad but will not guarantee that they are good. Parts
may test ok with no voltage applied but then fail once operated in-circuit.
Connections may open up when they heat up. The magnetron may short out when
full voltage is applied.
Don't overlook the wiring as no heat or erratic operation can result from
simple bad connections!
An alternative way of determining if the problem is in the control circuits
(triac, relay, wiring) or microwave generator (HV transformer, HV capacitor,
HV diode, magnetron, wiring, etc.) is to connect the HV transformer primary
directly to a line cord and plug. Tape the removed wire lugs to prevent
shorts.
Plug the transformer cord into a switched outlet strip which includes a fuse
or circuit breaker.
Put a cup of water into the oven cavity to act as a load.
* Power the oven via its line cord. Initiate a cook cycle. It should go
through the normal cycle (of course no heat) without blowing the fuse or any

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unusual sounds. If there is a problem in this case, something in the
controller or its wiring is shorted.
* Now, initiate a 1 minute cook cycle on HIGH and with the oven running,
switch on the HV transformer.
- If the transformer or other HV components are faulty, the outlet strip
fuse will blow or circuit breaker will trip. Or, if a lamp is plugged
into the outlet strip at the same time, it will likely dim significantly
due to the heavy load before the fuse or breaker cuts out.
- If the problem is with the triac or its drive, the oven will now heat
normally. When the cook cycle is near its end, switch off the outlet
strip. Check the water's temperature.
More complete information on testing and replacing the individual components
is provided in the next few sections.

33. 33
PCB(Printed Circuit Board)
INTRODUCTION
A PCB (printed circuit board) or PC board is a piece of phenolic or glass-epoxy board with
copper clad on one or both sides. The portions of copper that aren't needed are etched off
leaving "printed" circuits which connect the components.
PCB is used to mechanically support and electrically connect electronic components using
conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive
substrate.
STEPS OF ASSEMBLING OF HALONIX CFL PCB
It is also sometimes referred to as printed wiring Board (PWB) or etched wiring board. A
PCB assembled with electronic components is called printed circuit assembly (PCA), OR
printed circuit board assembly (PCBA).
PCBs are rugged, inexpensive and highly reliable.
The electronics industry's PCB design, assembly, and quality control needs are set by standards
that are published by the IPC organization.

34. 34
They have setup State-of-the-art new generation Fully Automatic SMT & A.I. facilities
with the capability to handle Lead Free Processes, for PCB Assembly, Testing, Burn-in &
Pack out etc.
 Environment Friendly Lead Free Process Capabilities.
 Electronic manufacturing for batch & bulk production.
 Assembly lines with ESD protected shop floor.
STEPS
 We have bare PCB on which we have to mount the various component (eg
capacitor, resistor, diode, jumper etc etc) to assemble it for HALONIX 8watt
and 15 watt cfl.
 There is mainly three different parts of assembling a pcb for cfl.
1. AI(automatic insertion).
2. RI(radically insertion).
3. MI(manually insertion).
4. SMT( surface mounted technology) .
 AI , automatic insertion can be done by using the universal sequencer,
in which the machine is automatic insert the component axially eg
diode ,jumper.,
 RI, radically insertion is also a type of automatic insertion but im this
insertion the standing component are inserted vertically eg capacitor.
 MI , manually insertion is the method of inserting the the component
manually.
 SMT , surface mounted technology is the technology in which the
very small component are sooted to the bare pcb , eg resistor.
In SMT the micro component are first glue by HDF glue to make the component
fix ten it can be passes though a oven for one minute to make permanent fix.

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AI MI
 A 8 watt HALONIX cfl have total different components , its have
 7diode(five IN(4007) and two FR diode(107-S))
 1 jumper
 1 zener diode
 8 SMD(274)
After completing the pcb the pcb is test by ICT i.e in circuit testing , it is a computer testing.
THE FUTURE
Because of their speed and convenience, microwave ovens have become an indispensable part of
modern kitchens. Many developments in the microwave market and allied industries are taking
place fairly rapidly. For example, foods and utensils designed specially for microwave cooking
have become a huge business. New feathe microwave ures will also be introduced in microwaves
themselves, including computerized storage of recipes that the consumer will be able to recall at
the touch of a button. The display and programmability of the ovens will also be improved, and
combination ovens capable of cooking with microwaves as well as by conventional methods will
become a standard household product.