Fix it Friday! (Logic Series 04) - Using a Current Tracer to Find Logic and Ground Shorts
Vložit
- čas přidán 20. 04. 2016
- In this video we demonstrate how to unravel stuck nodes, and find shorts to ground using the HP 457A Current Tracer and a Logic Pulser.
WARNING:
If you rely on the information in this content you do so at your own risk and you are responsible for the results. You hereby release Create!, it's affilates, subsidiaries, and any person included in the making of this content expressly or implicitly from any and all actions, claims, or demands that you, or any person including heirs, distributees, guardians, next of kin, spouse, or legal representatives
now have, or may have in the future for injury, property damage, death or any other liability that may result from use, misuse, or reliance on information provided in this content.
⭐⭐⭐⭐⭐ Outstanding glimpse into the 547A. Thank you 👍😁
Very good and I love the current probe. I’m looking for some hp logic probes for my collection they are very expensive in the the UK. I always wondered will a logic pulse damage a gate output ?
Very useful! I just ordered a set of the 545-548 on eBay.
I was working on a homebrew computer the other day, and it turns out one of my 74574's on the data bus was completely shot. My power supply was pushing over 1.5W through the chip, and I thought it was some issues with other chips in the area and something to do with floating pins(I had built half the thing before testing, and had also never worked with some of those chips before) but the dead chip was just pushing everything it was connected to to ground. Having one of those current probes would have made it a 10 second diagnosis.
Current tracer and pulser
very nice device, but cost is very prohibitive, there is another equivalent product?
Nice burgertime board
Is there a modern equivalent of 547a? The original one is cost prohibitive :)
*GRACIAS*
What's the model of your logic pulser?
great video
can you explain how the video section works on arcade pcb and troubleshooting?
Sure! We can put that in the cue. Thanks for the idea!
It will be great if you can show how to use the tracer to detect the short with a real example.
What's the difference/advantage of the current tracer compared to a logic probe ?
Thanks in advance !
zauche81 a logic tracer is for detecting shorts and following the short current path to its source. A logic probe will only show the logic level from the detected voltage on that node, which may not vary if there is a short.
I'm sorry that is impossible to find a place to buy it!
Those ceramics are probably RAM, that's why they draw more current. For GND-shorts why not just use a multimeter set to diode-test, placing one probe on GND and just swipe the other probe along the pins listening for the beep? That's alot quicker than using the tracer. Also you can just use your hand to find any hot or shorted chip, which appart from RAMs should not get much warmer than the rest of the logic on the board.
Btw how did you "sabotage" that coupling cap? You didn't short it (?), or your PSU would overlaod and shut down.
That's true, it would be faster. But, unless I misunderstand you, when you find the stuck node, there's no way to know using the continuity tester which chip is at fault without pulling chips or cutting traces, and in a more complicated game, where tons of stuff is attached to say, a data bus, this can get pretty ugly. The current tracer gives us the ability to follow the direction of the short. Also, just because a chip is hot, does not mean that it's shorted. I could be getting hot because it's supplying current to a direct short.
Thanks for the reply I really appreciate feedback!
You could just cut the one suspected pin, no need to pull the complete chip, not cutting any trace. Usually if the chip is uncommonly hot I've found it to be bad, but as you say there may be several aspects to it.
Accidentally I'm hook 12v in my board
Where I need to start?
I have 2v in out of the reguutor