using a logic analyzer

dyno

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What's the best way to connect the leads from a probe to a game board? Do I connect to am ic and is there a good tutorial out there on learning to use a logic analyzer?
 
connect black lead to a ground rail and the red lead to a +5 volt source.
the trick is knowing what state the chip leg you are testing is supposed to be in. thats the whole thing. knowing if its held high, held low, pulsing, etc.
for instance, if you determine leg 7 of an IC chip is held high, is that the state its supposed to be at? if you know its supposed to be low and its high, then you know there is a problem. the problem could be another chip "upstream" or even "downstream" of the problem leg of the chip. you will need to look at the schematic to determine which way the circuit or electron flow is going.
when you get good at it then you can quickly determine which circuit is at fault or why but that takes experience and good schematic reading.
 
connect black lead to a ground rail and the red lead to a +5 volt source.
the trick is knowing what state the chip leg you are testing is supposed to be in. thats the whole thing. knowing if its held high, held low, pulsing, etc.
for instance, if you determine leg 7 of an IC chip is held high, is that the state its supposed to be at? if you know its supposed to be low and its high, then you know there is a problem. the problem could be another chip "upstream" or even "downstream" of the problem leg of the chip. you will need to look at the schematic to determine which way the circuit or electron flow is going.
when you get good at it then you can quickly determine which circuit is at fault or why but that takes experience and good schematic reading.

OK...
Did the original poster mean Logic "Analyzer" or Logic "Probe"?
Both are mentioned in the original post and they are two very different animals.

Ed
 
Sorry my mistake I meant the leads from a pod for a logic analyzer.

Yup, very different.

OK - exact leads depends on logic analyzer. Mine have miniature clips for attaching directly to the IC legs. I also have IC clips - these are oversized plastic clothes pin type clips with a lead per pin of the IC.

Genericall speaking, you will first need to tie to ground.
Then tie signal leads to the signals you want to watch.
For example, one lead to an inverter input pin, next lead to the inverter output pin. Watch the traces on the logic analyzer... one trace should be exactly opposite of the other.

Using the logic analyzer, you can watch inputs and outputs of gates to verify if a gate is functioning or not. You can also watch data and address lines from CPU to find stuck or bad lines. Very useful!

But, like I said before, the exact method of hooking it up depends on which specific logic analyzer you have.

I have three -
A Gould Biomation (oversized boat anchor).
Two HP 1631D's
The HP's are quite handy for working on slow stuff like arcade/pinball boards.

Ed
 
Thanks for the info on where to hook up the leads, mine is a sony/tektronix 338. It is an older analyzer but it has 32 channels and I got if for $50 with 4 pods. It uses the IC clips like the ones you described as clothes pegs.. I am still learing so how do you know if the data lines or address lines are stuck or bad? What would I be looking for on the analyzer? I have been trying to find a good tutorial online regarding logic analyzers but am not having much luck.
 
I don't think there will be lesson anywhere teaching you about how to use logic analyzers because this is implied logic.

To use a logic analyzer you must i.d. the logic chip being analyzed, and then connect your logic probe channels to the inputs and outputs of the logic portions of a logic chip. Like if it's an AND logic chip then you monitor logic inputs for a 1 - high state and then monitor the output for a corresponding 1 - high state according to the truth table of the logic chip being analyzed.

This would help i.d. 7400 series logic chips -

http://www.kpsec.freeuk.com/components/74series.htm

http://www.unitechelectronics.com/7.../www.unitechelectronics.com/7400-7448data.htm
 
You need to have an understanding of digital logic before you can use either a logic probe or a logic analyzer.

Read the data sheets for the chips and you'll find timing diagrams that show how the lines are supposed to be activate to get the inputs/outputs you need.

RJ
 
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