FORM 2
THE PATENT ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE: “A SYSTEM FOR TESTING PRINTED CIRCUIT BOARD (PCB) SUB-ASSEMBLY AND METHODS THEREOF”
NAME AND ADDRESS OF THE APPLICANT: TATA MOTORS LIMITED, an Indian company having its registered office at Bombay house, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra, INDIA.
Nationality: INDIAN
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

TECHINCAL FIELD
Embodiments of the present disclosure relate to an Engine Control Unit (ECU), more particularly relates to a system for testing Printed Circuit Board (PCB) sub-assembly.
BACKGROUND OF THE DISCLOSURE AND PRIOR ARTS
The importance of the testing process has been magnified by the requirements of the modern manufacturing environment. In electronics mass production manufacturing facilities, an attempt is often made to achieve 100% quality assurance of all parts, subassemblies and finished goods in order to achieve 100% productivity on production line.
A common manufacturing flow of an electronic product from its bared PCB to finished product is as below,
■ Bare PCB,
■ SMD (Surface Mount Devices) components assembly, - Inspection of PCB for SMD components assembly
■ Conventional components assembly

- Electrical test
- Functional test
■ Enclosure assembly
- Final functionality
An electronic circuit, with both conventional as well as SMD components on the PCB requires to first assemble the SMD components, as by nature they are in very small size and get assembled with an automatic SMD soldering machine.
After assembling the SMD components on PCB and before the conventional component assembly, it is required to test the PCBs sub-assembly, so as to restrict the faulty PCB subassembly at earlier stage to minimize the final failures.
One way to test a PCB is provided by making connection between the PCB to be tested and the testing circuits of the device by conductive needles guided by at least one

perforated guiding plate as provided in U.S. Patent No. 5216358. The device for testing a PCB is made by the connection between the PCB to be tested and the testing circuits of the device which is ensured by conductive needles guided by at least one perforated guiding plate. The PCB to be tested comprises at least one standard pattern included in a predetermined set of standard patterns of closely spaced contact regions. An intermediate plate has a first surface, turned towards the PCB to be tested, comprising the first pattern of pads arranged according to the standard pattern and a second surface comprising a second pattern of pads regularly arranged according to a pitch compatible with that of the needles, each pad of the first surface being electrically connected to a pad of the second surface.
Another way to test the PCB is by providing a two-sided probe and clamshell fixture embodiment as provided in U S Patent No. 5436567. The two-sided probe and clamshell fixture embodiment comprises a vacuum-actuated bed-of-nails for probing the bottom side of printed circuit board (PCB) device-under-test (DUT) and a pushrod-actuated bed-of-nails for probing the top side of the PCB device-under-test. The fixture comprises a base, a bottom frame, and a bottom plate that are sealed for vacuum-actuation by a gasket. When in place, the DUT completes the vacuum seal and the bottom bed-of-nails which includes a patterned array of spring loaded probe pins reaches through the bottom frame and operate a set of gear boxes attached to the outer edges of a top plate within a top frame. A patterned array of spring loaded probe pins reaches through the top plate to contact probe points on the top side of DUT when a vacuum applied to the bottom assembly causes the pushrods to advance and operate the gear boxes. The gear boxes reverse the direction of force received to cause the topside pushrod-actuated bed-of-nails to engage the DUT.
Yet another way to test the PCB is provided in US Patent No. 5909124. The Apparatus for testing an electrical circuit has a base for receiving a printed circuit board carrying the electrical circuit, wherein the base section includes a plurality of test pins for contacting a corresponding plurality of solder pads formed on a surface of the circuit board, a cover section comprising a test head facing an opposite surface of the printed circuit for shorting together a plurality of contacts of a component of the electrical circuit connected to the plurality of solder pads and mounted on the opposite surface of the circuit board, means for

applying a stimulus signals to at least one test pin, and means for detecting a signal at a second test pin.
Still another way to test the PCB is provided in US Patent No. 3830956. The construction of printed circuit board is disclosed in which conductive pads are arranged on the surface of a printed circuit board for contacting by probes of a test rig and are connected to conductive tracks of the circuit board which otherwise may be inaccessible for test purposes.
Still another way to test the PCB is provided in US Patent No. 3144210, wherein a method and apparatus for detection of manufacturing defects during in-circuit testing is provided. The embodiment utilizes an onboard controllable signal source and/ or an external signal source, in combination with capacitive sensors, to detect defects. In an embodiment, prediction equations are implemented to increase both the efficiency and effectiveness of defect detection and location.
STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure provides for a system (1) for testing Printed Circuit Board (PCB) sub-assembly (2), said system (1) comprising a clamping device (3) comprising a toggle clamp (3a); a plate (3b) fixed onto a glass plate (3c) and said plate (3b) is connected to base of the toggle clamp (3a); and plurality of studs (3d) connected to bottom of the glass plate (3c), which lie on unpopulated portion of the PCB sub-assembly (2); plurality of contacting means (4) placed between the PCB sub-assembly (2) and a conventional components assembly (5); a programmer (6) connected to the PCB sub-assembly (2) through a connector (7) to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and an user interface (9) connected to the PCB sub-assembly (2) through connectors (10) assembled on the conventional components assembly (5) for providing input to the PCB sub-assembly (2), also provides for a method of testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of placing the PCB sub-assembly (2) on top of contacting means (4); resting studs (3d) on the PCB sub-assembly (2); pressing toggle clamp (3a) to bring the PCB sub-assembly (2) in contact

with the contacting means (4) to ensure electrical contact with a conventional components assembly (5); and providing input to the PCB sub-assembly (2) through connectors (10) and monitoring output corresponding to the input for testing the PCB sub-assembly (2), and also provides for a method of assembling a system (1) for testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of fixing a plate (3b) onto a glass plate (3c); connecting a toggle clamp (3a) to the said plate (3b); connecting plurality of studs (3d) to bottom of the glass plate (3c); attaching the PCB sub-assembly (2) to the plurality of the studs (3d); placing plurality of contacting means (4) between the PCB sub-assembly (2) and a conventional components assembly (5); connecting a programmer (6) to the PCB sub-assembly (2) through a connector (7) to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and connecting a user interface (9) to the PCB sub-assembly (2) through connectors (10) assembled on the conventional components assembly (5) for providing input to the PCB sub-assembly (2).
OBJECTS OF THE DISCLOSURE
The object is to provide a system (1) for testing Printed Circuit Board (PCB) sub-assembly (2).
Another object is to provide a method of testing a Printed Circuit Board (PCB) sub-assembly (2).
Yet another object is to provide a method of assembling a system (1) for testing a Printed Circuit Board (PCB) sub-assembly (2).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

FIG. 1 shows a system for testing PCB sub-assembly, and
FIG. 2 shows a clamping device used for testing the PCB sub-assembly.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE DISCLOSURE
In the following detailed description, reference is made to the accompanying figures, which form a part hereof. In the figures, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, and figures are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
This disclosure is drawn, inter-alia, to a system (1) for testing Printed Circuit Board (PCB) sub-assembly (2) and a method of testing the PCB sub-assembly.
Referral Numerals:
1: System for testing Printed Circuit Board (PCB) sub-assembly,
2: PCB sub-assembly (Unit Under Test)
2b: Bare PCB of the PCB sub-assembly,
2c: Surface Mount Devices (SMD) of the PCB sub-assembly,
2d: Test points on the PCB sub-assembly,
3: Clamping device,
3a: Toggle clamp,
3b: Plate,

3c: Glass plate,
3d: Plurality of studs,
4: Plurality of contacting means (bed of nails),
4a: Plurality of pins,
4b: Holes on the contacting means,
4c: Glass laminated sheet of the contacting means,
5: Conventional components assembly,
6: Programmer,
7: Connector to the programmer (6),
8: Microcontroller,
9: User interface,
9a: Automatic control,
9b: Manual control,
10: Connector to the interface, and
11: In Circuit Serial Programming (ICSP) cable.
The present disclosure is in relation to a system (1) for testing Printed Circuit Board (PCB) sub-assembly (2), said system (1) comprising a clamping device (3) comprising a toggle clamp (3a); a plate (3b) fixed onto a glass plate (3c) and said plate (3b) is connected to base of the toggle clamp (3a); and plurality of studs (3d) connected to bottom of the glass plate (3c); plurality of contacting means (4) placed between the PCB sub-assembly (2) and a conventional components assembly (5); a programmer (6) connected to the PCB sub-assembly (2) through a connector (7) to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and an user interface (9) connected to the PCB sub-assembly (2) through connectors (10) assembled on the conventional components assembly (5) for providing input to the PCB sub-assembly (2).
In one embodiment of the disclosure the PCB sub-assembly (2) comprises a bare PCB (2b) and Surface Mount Devices (SMD) (2c) mounted on the bare PCB (2b).

In one embodiment of the disclosure the contacting means (4) are nails, said contacting means (4) have plurality of pins (4a) inserted into holes (4b) in a glass laminated sheet (4c) to make contact with test points (2d) on the PCB sub-assembly (2).
In one embodiment of the disclosure the user interface (9) comprises automatic control (9a) and manual control (9b) for testing the PCB sub-assembly (2).
In one embodiment of the disclosure the manual control (9b) is adapted to provide input to the PCB sub-assembly (2) through the programmer (6).
In one embodiment of the disclosure the plate (3b) is made of metallic or non-metallic material selected from a group comprising aluminum, glass wool, plywood.
In one embodiment of the disclosure the microcontroller (8) is programmed through an In Circuit Serial Programming (ICSP) cable (11) for controlling I/O of the system (1).
The present disclosure is in relation to a method of testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of placing the PCB sub-assembly (2) on top of contacting means (4); resting studs (3d) on the PCB sub-assembly (2); pressing toggle clamp (3a) to bring the PCB sub-assembly (2) in contact with the contacting means (4) to ensure electrical contact with a conventional components assembly (5); and providing input to the PCB sub-assembly (2) through connectors (10) and monitoring output corresponding to the input for testing the PCB sub-assembly (2).
In one embodiment of the disclosure the PCB sub-assembly (2) is tested automatically or manually.
The present disclosure is in relation to a method of assembling a system (1) for testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of fixing a plate (3b) onto a glass plate (3c); connecting a toggle clamp (3a) to the said plate (3b); connecting plurality of studs (3d) to bottom of the glass plate (3c); attaching the PCB sub-assembly (2) to the plurality of the studs (3d); placing plurality of contacting means (4) between the PCB sub-assembly (2) and a conventional components assembly (5);

connecting a programmer (6) to the PCB sub-assembly (2) through a connector (7) to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and connecting a user interface (9) to the PCB sub-assembly (2) through connectors (10) assembled on the conventional components assembly (5) for providing input to the PCB sub-assembly (2).
FIG. 1 illustrates the system (1) for testing PCB sub-assembly when the conventional components assembly is yet to be assembled on this unit.
The flow of assembling of the Engine Control Unit (ECU) assembly is assembling bare PCB (2b) with SMD (2c), conventional components assembly (5), thereafter testing and packaging. In this conventional way of manufacturing/assembling, the PCB sub-assembly is tested for functioning at the final stage of assembling. Due to this, the fallout of the PCB sub-assembly happens at its final production stage. In order to prevent the loss due to this, an automated method is designed in which the PCB sub-assembly is tested by making contact with the conventional components assembly. The PCB sub-assembly is connected with conventional components assembly through bed of contacting means for example nails to form a complete assembly and practically without completing the assembly. A microcontroller on this virtually completed assembly is programmed through an In Circuit Serial Programming (ICSP). The system (1) does full function testing of the PCB sub-assembly. The system for testing automatically controls the relays whose contact drives inputs of the Unit Under Test (UUT). The system also has manual mode to provide input signals to the PCB sub-assembly and a corresponding output is observed in the form of lamps/ LED’s. By this automatic embedded test system for PCB sub-assembly, the fallout of the PCB sub-assembly is detected in early stage and thus reducing the final fallout and increasing the productivity to 100% by reducing production time, rework and thus the total manufacturing cost.
To perform full function testing of the sub-assembly, the test rig requires overall assembly of PCB (conventional as well as SMD). This entire process is done automatically.
Hence, to virtually connect the UUT, with other conventional components, it is required to assemble a same board/ PCB with only conventional components which has to electrically

connect with the SMD board (a Unit Under Test) to form a complete PCB. For making electrical connections between SMD & conventional component board, a bed of nails is used which forms a connection from SMD component to conventional components.
FIG. 2 illustrates the system (1) consists of a clamping device (3) which clamps the unit under test on the test system (1). A toggle clamp (3a) is a fastening device that holds objects tightly together to prevent movement or separation through the application of inward pressure. An aluminium plate (3b) is fixed to a glass plate (3c) with two bolts. Six studs (3d) are placed on the acrylic glass plate in such a way that studs (3d) will not foul on SMD components and lie on unpopulated portion of the PCB sub-assembly (2). The toggle clamp (3a) presses the aluminium plate (3b) mounted on the glass plate (3c) which presses the studs (3d), which finally presses Unit Under Test (UUT) on the bed of contacting means (4) for example nails to ensure electrical contact.
The UUT is a PCB mounted with SMD components and a programming connecter (7). The general manufacturing steps for an ECU are manufacturing the bare PCB, soldering SMD components with the bare PCB to form a PCB sub-assembly and assembling conventional components assembly with the PCB sub-assembly. Before assembling the PCB sub-assembly with the conventional components assembly, it is required to check if the PCB sub-assembly is ok at this stage. If the PCB sub-assembly is ok, then only the PCB sub-assembly is taken for assembling with the conventional components assembly and thus preventing fall out at the later stage. In order to test the full functionality of the components, the PCB sub-assembly has to be completed virtually without actually assembling with the conventional components assembly. This is carried-out with the help of bed of contacting means (4) (nails). The bed of nails (4) has 124 pins (4a) inserted into 124 holes (4b) in a glass laminated sheet (4c) which are aligned using tooling pins to make contact with 124 test points (2d) on the PCB sub-assembly (2). The other end of the bed of nails (4) is connected to the PCB sub-assembly (2) with conventional components assembly (5) by wires. The test points (2d) are designed in such a way that all conventional components are covered in the electrical connection established through bed of nails (4). The selection of test points (2d) ensures that the PCB sub-assembly (2) is completed with

connecting the conventional components assembly (5) via bed of nails (4). The bed of nails (4) contains an array of small, spring-loaded pogo pins; each pogo pin makes contact with one node in the circuitry of the PCB sub-assembly also referred as Unit Under Test (UUT). The UUT rests on the bed of nails (4) which makes contact with the conventional components assembly. The clamping device (3) clamps the UUT (2) on the bed of nails (4). By pressing the UUT (2) down against the bed of nails (4), reliable contact is made quickly and simultaneously with hundreds or even thousands of individual test points within the circuitry of the UUT (2). The hold-down force is provided by means of toggle clamp (3a) pulling the UUT (2) downwards onto the bed of nails (4) and thus ensuring the electrical contact. The bed of nails (4) rest on the pads of conventional components assembly (5) and thus virtually completing the assembly of the component.
The programmer (6) is used to program the microcontroller (8) on the UUT (2) through the In Circuit Serial Programming (ICSP) connecter (10). A software program is used to program the microcontroller (8) such that the outputs are on depending on the required inputs. The programming logic gives the required input to make a particular output on. This is again checked by logic if the required output has become on and if so it switches the input to make the output off. The logic checks the output for off stage and if found ok the same procedure is applied for the next digital input. For frequency inputs functional working range of frequency is checked. For analog signal working voltage range is checked. The logic is returned in such a way that it sequentially confirms these checks of all inputs and while doing so all outputs are also covered. The ICSP cable (11) between the programmer (6) and the ICSP connects the Supply, Ground, Reset, Clock and Programming pins of the microcontroller (8) to the programmer (6). After programming, the ICSP cable (11) is removed and the programmer (6) is disconnected from the test system (1).
In one embodiment, the UUT (2) is connected to the test system (1) user interface (9) through connecters X1 and X2 (10) assembled with conventional components assembly (5).

In an exemplary embodiment, when ignition input is made on each and every input of the UUT (2) is tested by giving corresponding voltages at the input and recording the expected output. The input voltage levels are automatically switched by relay contacts in automatic control (9a) and the corresponding output is toggled on and off. If the expected output is not received this confirms that the problem lies in the corresponding input/output, thus the test system points out where exactly the problem is present in UUT (2). The above method is followed for each and every input. The types of inputs supported by the automatic control (9a) are digital, analog and frequency type. The type of outputs supported are digital, analog and PWM. This covers almost all inputs and outputs used in automotive ECU’s. By following the same procedure for each and every input, output and power supply assembly the full functional testing is covered in this system. The UUT (2) behavior for input open, short to supply and short to ground and output open, short to supply and short to ground is also tested. The programming portion of the unit is also covered by ensuring UUT (2) is properly programmed by the ICSP cable (11) through the programmer (6).
In an alternative embodiment, the test system (1) also has provision for manual control (9b). The respective inputs can be toggled manually with help of switches S1, S2……to Sn and outputs can be observed on lamps L1, L2…. to Ln. When the test rig is in manual mode the switches and lamps are directly connected to the virtually completed assembly of UUT (2) connected with bed of nails (4) to the conventional components assembly (5). The connecters X1 and X2 (10) are also assembled as apart of conventional components assembly (5). The switches and lamps are connected to a pigtail having wiring harness side connecters (10) of X1, X2 which connects to the UUT (2) through these connecters (10) X1 and X2.
In one embodiment, the test system (1) can be customized for different PCB sub-assembly platforms. With change in PCB sub-assembly (2), bed of nails (4) and conventional components assembly (5) and the remaining test setup can be utilized.

The PCBs sub-assembly (2) can be automatically fed to the test system (1) via a conveyer belt. During the assembly process the PCB sub-assembly from conveyor slides on bench of the test system (1). The toggle clamp (3a) is energized which clamps the UUT with the bed of nails. Advantages
An automatic embedded test system for PCB sub-assembly in which the PCB subassembly i.e. PCB assembled with SMD components and conventional components yet to be assembled is tested for full functionality of the unit.
A method of performing full functional testing on PCB sub-assembly by virtually completing the assembly without actually assembling the conventional components assembly and programming the microcontroller on this virtually completed assembly through ICSP is carried out.
The test system of virtually connecting the PCB sub-assembly (semi-finished product) and the PCB sub-assembly with conventional components assembly and thus forms one complete finished product.
Method of testing semi-finished product by virtually forming a finished product and detecting failure at early stage and thus reducing the cost and increasing production yield of the product.
Equivalents
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term

"includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either

of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

We claim:
1. A system (1) for testing Printed Circuit Board (PCB) sub-assembly (2), said system (1)
comprising:
a. a clamping device (3) comprising a toggle clamp (3a); a plate (3b) fixed onto a
glass plate (3c) and said plate (3b) is connected to base of the toggle clamp (3a);
and plurality of studs (3d) connected to bottom of the glass plate (3c) which lie on
unpopulated portion of the PCB sub-assembly (2);
b. plurality of contacting means (4) placed between the PCB sub-assembly (2) and a
conventional components assembly (5);
c. a programmer (6) connected to the PCB sub-assembly (2) through a connector (7)
to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and
d. an user interface (9) connected to the PCB sub-assembly (2) through connectors
(10) assembled on the conventional components assembly (5) for providing input to
the PCB sub-assembly (2).
2. The system (1) as claimed in claim 1, wherein the PCB sub-assembly (2) comprises a bare PCB (2b) and Surface Mount Devices (SMD) (2c) mounted on the bare PCB (2b).
3. The system (1) as claimed in claim 1, wherein the contacting means (4) are nails, said contacting means (4) have plurality of pins (4a) inserted into holes (4b) in a glass laminated sheet (4c) to make contact with test points (2d) on the PCB sub-assembly (2).
4. The system (1) as claimed in claim 1, wherein the user interface (9) comprises automatic control (9a) and manual control (9b) for testing the PCB sub-assembly (2).
5. The system (1) as claimed in claim 4, wherein the manual control (9b) is adapted to provide input to the PCB sub-assembly (2) through the programmer (6).
6. The system (1) as claimed in claim 1, wherein the plate (3b) is made of metallic or non-metallic material selected from a group comprising aluminum, glass wool, plywood.

7. The system (1) as claimed in claim 1, wherein the microcontroller (8) is programmed through an In Circuit Serial Programming (ICSP) cable (11) for controlling I/O of the system (1).
8. A method of testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of:
a. placing the PCB sub-assembly (2) on top of contacting means (4);
b. resting studs (3d) on the PCB sub-assembly (2);
c. pressing toggle clamp (3a) to bring the PCB sub-assembly (2) in contact with the
contacting means (4) to ensure electrical contact with a conventional components
assembly (5); and
d. providing input to the PCB sub-assembly (2) through connectors (10) and
monitoring output corresponding to the input for testing the PCB sub-assembly (2).
9. The method as claimed in claim 8, wherein the PCB sub-assembly (2) is tested automatically or manually.
10. A method of assembling a system (1) for testing a Printed Circuit Board (PCB) sub-assembly (2), said method comprising acts of:
a. fixing a plate (3b) onto a glass plate (3c);
b. connecting a toggle clamp (3a) to the said plate (3b);
c. connecting plurality of studs (3d) to bottom of the glass plate (3c);
d. attaching the PCB sub-assembly (2) to the plurality of the studs (3d);
e. placing plurality of contacting means (4) between the PCB sub-assembly (2) and a
conventional components assembly (5);
f. connecting a programmer (6) to the PCB sub-assembly (2) through a connector (7)
to program a microcontroller (8) placed on top of the PCB sub-assembly (2); and
g. connecting a user interface (9) to the PCB sub-assembly (2) through connectors
(10) assembled on the conventional components assembly (5) for providing input to
the PCB sub-assembly (2).

11. A system (1) for testing Printed Circuit Board (PCB) sub-assembly (2), a method of testing a Printed Circuit Board (PCB) sub-assembly (2) and a method of assembling a system (1) for testing a Printed Circuit Board (PCB) sub-assembly (2), are substantially as herein above described and as illustrated in accompanying drawings.