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Title: Testing odd components Post by: channelmaniac on April 17, 2009, 02:13:16 AM This thread will be dedicated to testing odd parts or doing uncommon tests on common and uncommon parts!
To kick it off, here's a way to test Triacs: Remove the device from the circuit, being VERY careful to ensure the circuit is not energized! Take a digital ohmmeter and test between the different legs on the device: T1, T2, and Gate. Each resistance test will be VERY high, if not infinity, EXCEPT for T1 to Gate. Gate to T1: 10 to 200 ohms T1 to Gate: Infinity T1 to T2: Infinity T2 to T1: Infinity T2 to Gate: Infinity Gate to T2: Infinity Now, there are some exceptions! Some Triacs will read from 10 to 200 ohms BOTH WAYS between T1 and Gate. Next, attach one meter lead to T1 and the other to T2. Use a screwdriver blade to short between T2 and Gate. The resistance between T1 and T2 will drop to around 15 to 50 ohms. If it does not, reverse the leads on T1 and T2 then try again. One way will read infinite and the other will read low resistance when T2 and Gate are shorted together. This method isn't foolproof, but is a good general test to check for a shorted triac. Title: Re: Testing odd components Post by: channelmaniac on January 28, 2010, 04:32:18 AM If you have an EPROM programmer from EETools that uses the Max Loader software and it doesn't support testing of a particular 74xx or 4xxx series logic chip, they can be added manually!
The lg.dat file in the c:\program files\EETools directory contains the data for those ICs. It is trivial to add items to that file, provided you structure them properly. Here are the values that can be entered into each spot: 0 - Logic Low Input 1 - Logic High Input L - Logic Low Output H - Logic High Output Z - (unknown at this time) C - (unknown at this time) X - (unknown at this time) G - Ground Pin V - Vcc, or Power Pin (+5v) An example of this is a 7421/74LS21/etc, which is a Dual 4-input AND Gate and not on the list of ICs for the burner to test. The logic table is as follows: Code: Inputs Output ALL 4 inputs must be high for the output to be high. Gate 1 uses pins 1, 2, 4, and 5 for input and 6 for the output. Gate 2 uses 9, 10, 12, and 13 for input and 8 for the output. Pin 7 is ground, pin 14 is Vcc (power), and both 3 and 11 are not used. A value of 0 is placed in the location of the unused pins. The structure of the data file for chip to be defined starts with a dot, the chip number, some spaces, and the # of pins on the chip. Code: .7421 14 So with this in mind, here is the entry for the 7421: Quote .7421 14 00000LGL00000V 10000LGL10000V 01000LGL01000V 11000LGL11000V 00010LGL00010V 10010LGL10010V 01010LGL01010V 11010LGL11010V 00001LGL00001V 10001LGL10001V 01001LGL01001V 11001LGL11001V 00011LGL00011V 10011LGL10011V 01011LGL01011V 11011HGH11011V This walks through all 16 possible combinations for the 4 inputs. It is possible to do this in as few as 5 lines, which is what the truth table (logic function table) shows, but for a more thorough test, all possible combinations for the inputs should be tested. This chip definition can be added to the end of the file or in the appropriate ordered place within the file. If it is placed at the end of the file then you must scroll all the way to the end of the file to choose it. The added benefit of defining the IC chip in this file is that it will then be used when clicking "Auto Find" to ID a chip. Enjoy! Title: Re: Testing odd components Post by: channelmaniac on May 22, 2013, 03:42:42 AM For the lg.dat file, it appears that X is for "don't care"...
Using that nomenclature, here is the text to add to the lg.dat file to test an Intel 8216 "4 bit bi-directional bus driver" IC. Code: .8216 16 If you put it at the top of the file, it will be the first chip in the list. A REALLY cool thing about adding this chip is that once added, the programmer will detect it using the "Auto Detect" function!!! Enjoy! Title: Re: Testing odd components Post by: channelmaniac on May 23, 2013, 01:07:17 AM Here is a 7489, 74289, AM27LS02, and Intel P3101A test:
Code: .7489 16 These chips have open collector outputs so they needed to be set to Z instead of H on outputs for high as there are no resistors tying the outputs high. This is for a 74189 (tri-state): Code: .74189 16 And this is for an AMD AM29701 which is identical to the 74189 except for having non-inverting outputs: Code: .29701 16 Title: Re: Testing odd components Post by: channelmaniac on May 23, 2013, 08:12:22 PM Here is the code to test the 82S16, a 256 x 1 bipolar RAM with inverted outputs. It also works for the Fairchild 93421 bipolar RAM and the test code is 1024 lines long.
It operates in this fashion: Write 0 to address 0 Read from address 0 .. Write 0 to address 11111111 (255) Read from address 11111111 (255) Then repeat for writing a 1 and reading it back for each address. It's too big to post as text, so here's an attachment. Enjoy! Title: Re: Testing odd components Post by: channelmaniac on May 23, 2013, 08:33:12 PM AMD AM25S09: Quad 2-input High Speed Register:
Code: .25S09 16 Title: Re: Testing odd components Post by: channelmaniac on June 09, 2013, 04:18:19 PM 8212 8-bit Input/Output Port:
Code: .8212 24 The last 8 lines are a bit redundant but it checks the chip with either STB held high or clocked (low-high-low pulse). First 5 lines checks interrupt function and after that the inputs and outputs are tested. Title: Re: Testing odd components Post by: channelmaniac on July 07, 2013, 08:12:48 PM 82S25 is the same as a P3101 for testing. :)
Here are a few more: Code: .8T97 16 8T38: The first 2 test the chip from Bus to Out (Input to Bus outputs disabled.) The 3rd tests the Input to Bus when the Input is high. The last three are a bit redundant. 8T96: Autofind will find it by itself. It's similar to the 8T98 but the enable lines must BOTH be toggled for all gates to be enabled. 8T98: Autofind will find it as either an 8T98 or an 8T96. The enable lines are separate on this chip: One controls 2 gates and the other controls 4 gates. Title: Re: Testing odd components Post by: channelmaniac on July 07, 2013, 08:59:58 PM 8T95: Identical to 8T96, but with non-inverting outputs:
Code: .8T95 16 8T28: Code: .8T28 16 8T26 is like the 8T28, but has inverted outputs. Wouldn't be too hard to create from the 8T28 script. Title: Re: Testing odd components Post by: channelmaniac on July 07, 2013, 11:35:53 PM Code: .26LS31 16 Can't do a 1488 as pin 1 is a negative power pin. |