abi SYSTEM 8 Instruction Manual Download Page 2

 

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INTRODUCTION 

 
The training board has two uses.  It is intended for use as a training aid for both customers 
and  ABI  distributors,  and  as  a  sales  tool  to  demonstrate  the  many  features  of  the 
BoardMaster and SYSTEM 8 ranges.  We have tried to highlight as many common PCB faults 
as possible as well as the common uses of instruments.   
 
Using the training board 
 
As  the  training  board  has  been  designed  to  serve  a  dual  purpose,  it  was  necessary  to 
simulate  the  wide  range  of  situations  encountered  when  diagnosing  board  faults,  as  well  as 
demonstrating the applications and ease of use of ABI products.  The training board therefore 
contains  a  wide  range  of  different  types  of  components,  with  switchable  fault  conditions, 
which can be used with most of the ABI test and fault-finding instruments. 
 
The  board  is  divided  into  three  distinct  sections.    A  digital  section  with  various  digital  ICs 
(including a microprocessor, memory and EPROM) is included to demonstrate the capabilities 
of our IC Test  Solution instruments.  An analogue section  contains analogue  components to 
demonstrate  the  functions  of  our  Analogue  V-I  and  Analogue  IC  Test  Solutions.    Finally,  a 
discrete section contains uncommitted discrete components to allow a more detailed analysis 
of  V-I  and  analogue  testing.    Products  that  combine  different  test  techniques,  such  as  the 
Diagnostic Solution and the BoardMaster 8000 PLUS, can be used on the entire board. 
 
The board can be used in two ways.  The relevant SYSTEM 8 instrument (e.g. the IC Tester) 
can be opened manually and configured to test a particular component on the training board.  
The switches for the component can be used to simulate a fault condition, by reference to the 
circuit  diagram  and/or  this  manual.    The  results  can  then  be  analysed  to  gain  an 
understanding  of  the  operation  of  the  system.    Alternatively,  the  training  board  package 
contains  a  CD-ROM  with  a  test  sequence  file  (TestFlow),  which  can  be  used  to  guide  the 
operator  through  a  sequence  of  tests  on  the  board.    All  instruments  are  opened  and 
configured  automatically,  leaving  the  operator  free  to  concentrate  on  analysing  the  results.  
Brief  instructions  and  explanations  are  also  shown  on  screen.    The  disk  also  contains  all 
necessary data files (e.g. digital pattern files, V-I data files etc.) which are required by some 
of  the  test  steps.    We  suggest  that  you  work  through  this  sequence  file  in  order  to  gain  a 
thorough understanding of the system.  You can also select individual steps in the sequence, 
if you wish to repeat a test. 
 
 
Using TestFlow 
 

ACTION 

On each step in the Test Instruction it will tell you what you need to do to carry out each test 
step. Instructions will include component location, switch settings and instrument operations. 
 
Most steps are independent of each other so  

you  can  jump  to  a  specific  test  if  you  wish. 

In normal operation click NEXT button to continue. 
 

DESCRIPTION 

The  Test  Instruction  describes  the  operation  being  carried  out  by  the  equipment  and  you. 
Each  step  in  the  TestFlow  is  setup  to  allow  information  to  be  easily  acccessed  without 
cluttering the screen. Each step in the TestFlow can show valid circuit and device conditions 
and also fault conditions. 
 
The TestFlow (system) is originally intended to highlight fault conditions with a failure or bad 
indication.  For  the  purposes  of  training  the  TestFlow  for  the  Training  board  will  indicate  a 
pass or good comparison if the correct action has been carried out by the operator, indicating 
that the particular point being covered in the TestFlow step has been correctly completed. 

Summary of Contents for SYSTEM 8

Page 1: ...EM 8 Board Fault Locator ABI Electronics Limited Dodworth Business Park Dodworth Barnsley South Yorkshire S75 3SP United Kingdom tel 01226 207420 fax 01226 207620 web www abielectronics co uk email sales abielectronics co uk ...

Page 2: ...y reference to the circuit diagram and or this manual The results can then be analysed to gain an understanding of the operation of the system Alternatively the training board package contains a CD ROM with a test sequence file TestFlow which can be used to guide the operator through a sequence of tests on the board All instruments are opened and configured automatically leaving the operator free ...

Page 3: ...es of circuit and fault conditions the techniques of fault with the equipment will be highlighted The PCB includes simple circuits for training in basic electronic principles The PCB is designed in sections to give optimum coverage for each aspect of the equipment Circuit and fault conditions are applied by making a switch connected to a PIC which in turn energises relays that switch in components...

Page 4: ...nd terminate the tests The ANALYSIS button opens the Analysis test results window The IC button toggles between the IC diagram and V I views after the test is completed The ACTUAL MASTER toggles changes between views when comparing two test results The Arrow controls are used to step through individual pins or groups of pins in the V I curve view COMMENT When running a TestFlow control and setup i...

Page 5: ... a device with corresponding thresholds for the device under test DUT For example the threshold for and AC device is as a CMOS device threshold so you must use the correct type to test the device properly TTL has a high threshold of 2 4V but the 74C type has a High threshold of 4 0V EXERCISE 3 BOARD FAULT LOCATOR POWER SUPPLY ACTION Attach the red and black power lead from the training board conne...

Page 6: ...hresholds Close the SETUP window Press the START button and observe the IC diagram dragging the test results display to one side if necessary DESCRIPTION The Voltage test quite simply looks at the voltage on each pin in turn and displays the result Much like measuring each IC pin with a Multimeter but much quicker When the voltage test is selected on its own the clip is not automatically orientate...

Page 7: ...rried out from a TestFlow or Live Comparison 2 Comparison results section indicates whether the Connections Voltage Thermal and V I results were the same as those for the saved device within the TestFlow 3 The Status window gives comment on the conditions the system finds present on the device and advises on requirement of Ground Clip COMMENT In normal one off testing there will only be the actual...

Page 8: ...connections test on its own may not always highlight the fault but it is an integral part of the ABI test philosophy without it you will not be able to effectively diagnose a PCB With a truth table test the integrity of the IC is tested to test it the system needs to obtain the circuit connections to the IC these Connections in turn can be used to compare against the connections of a good IC or ag...

Page 9: ...tion on Pin 7 Press NO GND switch and ensure LED lights DESCRIPTION Operating the No GND switch alters the circuit so that the device Ground pin does not present a valid ground to the tester COMMENT In cases like this the first steps are to ensure the clip is connected attached properly and that the BFL supply is correctly referenced If problem remains you must check the continuity of the ground p...

Page 10: ...rity of the IC giving a functional PASS FAIL result The circuit conditions will be taken into account prior to the test and the expected truth table result will be modified accordingly The test will be carried out in LOOP mode as this is the best way to show the changing activity around the IC during testing You will see from the results that the IC s Truth Table result is a PASS given by the ACTU...

Page 11: ... on TTL type devices Whenever there is a Floating pin identified there is likely be an indication of a MID LEVEL voltage As the pin is not being driven by a valid logic level and is floating between there will be an indication of a Mid High or a Mid Low voltage It is most important that you understand that this condition will be normal if the device has a floating pin due to its lack of connection...

Page 12: ...witch and observe the input on Pin 13 change to IPML DESCRIPTION Supplying the input through a potential divider creates both of the conditions Note from the circuit that external components as well as fault conditions can create Mid Levels COMMENT Input Mid Low and Input Mid High can be present for a large number of reasons not necessarily due to a fault condition Circuit design and circuit condi...

Page 13: ...nal diode structure of the gate presents a high impedance to the tester on the floating pin This is a typical feature on TTL devices COMMENT The Shorts presented to the inputs are taken into account as valid circuit conditions when the Truth Table test is run This test shows the ability of the system to adapt to different circuit conditions and still give valid results for the IC Test without any ...

Page 14: ...observe indication STOP the test and read the description DESCRIPTION The input threshold levels on IC Tester can be changed in the SETUP dialogue box For TTL logic the default settings are as follows LOW 0 5V SWITCHING 1 2V HIGH 2 4V When a functional test is executed the outputs of the IC under test are interpreted by comparing them with the preset threshold voltages They would normally be eithe...

Page 15: ... if the output is driving an input of another gate or device that was applying a loading effect to such an extent that the driving stage could not reach its normal output voltage This shows that a MID LEVEL fault shown on the output of one IC may in fact indicate a problem elsewhere in the circuit as in the example on the training board EXERCISE 19 OUTPUT SHORTS ACTION Press START on the IC Tester...

Page 16: ...gnal derived from the clock is present on one or more pins of that IC then a SIGNAL message may appear in yellow on those pins This message is an indication that a changing signal has been detected on that pin The test may be affected in such a way that a good IC could FAIL COMMENTS Changing signals on the board under test are one of the biggest causes of spurious test failures Even if they do not...

Page 17: ...stable output to the IC we are testing This enables the correct logic level to be driven into the IC for the Truth Table test COMMENTS When using the BDO signals you must ensure that the point at which you connect the BDO signal is not directly connected to the IC under test otherwise the system will be driving itself and you will get a LOAD indication Note that the BFL inputs are capable of detec...

Page 18: ...est the SYSTEM 8 pin drivers must output a clock signal to the CLK pin pin 2 to test the functionality of the IC In this situation the existing clock on the board under test is backdriven by the SYSTEM 8 pin driver This process requires larger than normal current of a magnitude that depends on the device being backdriven It is particularly large when driving a pin that is in the LOW state since th...

Page 19: ...EM 8 software is aware of the ICs that may require the ground clip and a warning is given in the analysis box after the test EXERCISE 23 INVALID LINKS ACTION Clip on U15 74LS161 Ensure Ground Clip is attached to TP95 GND and BDO LOW is attached to TP84 DIS CLK Press STARTon the IC tester Press INVALID LINK and COUNTER RELOAD Observe Failure indicators in both cases DESCRIPTION Invalid LINKS can be...

Page 20: ... board will ensure that only one output at a time can be enabled From studying the circuit you can see that the tester can backdrive the Enable signal Pins 1 19 to carry out a complete and effective test on this device as the Address lines on the other device on the bus U10 are not enabled so there will be no output contention COMMENTS The Preliminary and connections tests carried out by the teste...

Page 21: ...ure all devices on the bus are in there High Impedance state By causing the Enable pin to be Logic High on IC U13 we can stop the interference The BDO is applied to the testpoint prior to the inverter that drives the enable pin COMMENTS Normally one or more of the BDO leads can be used to disable other ICs on the board to allow the test to PASS Depending on the design it may be simpler to disable ...

Page 22: ...f the IC is not known This will only work if the IC is functional If the IC is faulty its functionality cannot be identified and therefore it will not be recognised If it is a good IC the IC Identifier will identify it and any ICs which are functionally and pin compatible providing that the IC is in the SYSTEM 8 test library COMMENTS The IC Identifier is ideal for identifying ICs with missing mark...

Page 23: ...6k by 8 Checksum C52D Press VERIFY button Note the Checksum result window Verifies OK EXERCISE 30 LIVE COMPARISON ACTION Add your own live comparison test here on the 74LS244 X2 U13 and U17 DESCRIPTION The Live Comparison feature needs two BFL modules to be fitted in the system 128 Channels Two boards of the same type are needed and all connections are duplicated for each module Setup and test are...

Page 24: ...orming digital V I tests COMMENTS You may find during this exercise that some pins do not compare exactly using the built in comparison algorithm This is because ICs from different manufacturers have slightly different characteristics This may even occur with ICs from different batches from the same manufacturer although in this case the differences would not be so great V I tests for digital IC p...

Page 25: ... clicking on the MASTER ACTUAL button DESCRIPTION In this test the SETUP has been changed to allow Power on tests to be run in conjunction with Power off V I tests Normally the V I test would require correct orientation of the IC Clip In this case the Connections test is carried out to orientate the clip position on the IC it is this information that is used to adjust the position of the V I trace...

Page 26: ...ually The Graphical Test Generator has an associated document provided on the CD Please refer to this document to understand fully the use of the Test Generator EXERCISE 35 SHORT LOCATION ACTIONS Connect SOIC clip to U10 Attach BDO LOW to TP1 to disable U13 and stop Conflict Press START on the IC tester and observe result You will see L2 on pin 18 and 16 If remove the Jumper J3 to BUS_SHORT connec...

Page 27: ...So far we have discovered that 2 pins on the bus are connected However because of the bus structure these two signals appear at many places on the board We must now find the exact location of the short using the Short Locator instrument The connections test in the previous test found LINKS between bus lines The exact location can be found with the Short Locator This has an audible indication to al...

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