Vcc is the 5V rail (after the PNP transistor acting as a power switch and the 5V regulator).
Okay. I’ll check it out and see what I can see.
Only once I was able to see the menu on the serial but I can't replicate it.
Found the bug
It's triggered when you enter the menu after no component was found or an error occurred. BTW, RX is also working in bit-bang mode now.
Thank you, madires!
I'm not sure I'm doing this correctly. I'm attaching a diagram of the board with the Voltage readings from my DMM. I'm also attaching a screenshot from my scope measuring at the NPN. If I haven't done something correctly with the scope, it's because I'm totally new to them. If you need any other type of view, please let me know and I will try again.
Thanks,
Jonathan
I’m powering the CT with a bench power supply
I'd say your power supply is pooched
I may not be using the scope correctly. I really have no idea what I'm doing. It's a Rigol MSO2102A. I have calibrated the probes, but that is it. I literally have never used a scope before. This is my literal first attempt at using it.
I'm guessing that I'm not connecting the ground wire in the right place or that there is a setting on the scope that I just don't have set up correctly for this type of measurement.
When I use the DMM, it reads near-perfect 9V at the source and near-perfect 5V at the transistor. The power supply is a brand new Rigol DP832.
Perhaps it would be important for me to tell everyone that both the DP and the MSO have been unlocked to their full potential.
I'm guessing that I'm not connecting the ground wire in the right place
Put the probe ground clip on negative supply, and the touch the probe tip to the same place you put your DMM. Also try probing Vcc at the ATMEGA328 pin 7
The tester should draw significantly less than 1A.
I'm guessing that I'm not connecting the ground wire in the right place
Put the probe ground clip on negative, and the touch the probe tip to positive.
LOL. I knew that much. What I didn't know is if it makes a difference which negative (where) on the board that I use. I used the one at the battery connector because it was easily available.
Are there settings on the MSO2102A (or a typical) scope that I need to be mindful of in order to take the measurement for DC?
I'm guessing that my Fluke 289 is not lying about the voltage being 9V (before the transistor) and 5V (after the transistor). So, it doesn't make sense that the scope is showing what it is showing. I thought the more likely scenario is that I'm using it incorrectly somehow.
What I didn't know is if it makes a difference which negative (where) on the board that I use. I used the one at the battery connector because it was easily available.
It's a common negative circuit, meaning it should be the same everywhere, so yes the battery connector is as good a place as any.
Are there settings on the MSO2102A (or a typical) scope that I need to be mindful of in order to take the measurement for DC?
Just choose a good timebase that will allow you to see the whole power-on transition. Or you could AC couple your scope, and use a single shot capture , triggered on a voltage rise of a volt or so.
I have no idea why your scope is showing a 3.3V sinusoidal waveform at mains frequency. Some kind of diagnostic function?
I don't know why it was showing a sine wave either. But, I did some poking around. For some reason, on the AY-AT board (or mine at least), the negative terminal on the battery connector is NOT a good place to put the ground for the scope. I think the DC connector has some sort of disconnect when something is plugged into it? Makes sense, perhaps, so that you aren't powering it both from an external DC supply AND a battery at the same time. 9V + 9V = bad.
Once I figured out how to use the trigger function, I was able to get valid readings. See attached. What you are seeing in terms of the change in voltage is when I touch the probe to the NPN. This is after the AY-AT is already on (I can tell by the red LED).
I'm truly sorry for my n00bness, but I do appreciate all the help!
What I'm guessing you need, however, is a trigger NPN at the time that the decoder is pressed. Is that correct? If so, that is proving difficult to accomplish logistically as I have to manually hold the probe in place on the bottom of the board. How does one set up the probes to that they stay in place while an external, manual, mechanical trigger is applied? I have nothing for the alligator clip and probe grabber to clip on to. Should I attach something to the solder joints temporarily for testing purposes?
<EDITED> misread previous post.
I have nothing for the alligator clip and probe grabber to clip on to. Should I attach something to the solder joints temporarily for testing purposes?
If needed, you can always temporarily solder wire(s), clip onto them, take measurements, and then desolder the wire(s) when done.
Only once I was able to see the menu on the serial but I can't replicate it.
Found the bug It's triggered when you enter the menu after no component was found or an error occurred. BTW, RX is also working in bit-bang mode now.
Hi Markus, thank you for looking at it
In the mean time I've noticed another small issue, possibly related to this bug:
If I try to measure a 3 pin component that happen to be a dead short, instead of measuring it as 2 small resistors, it enters the menu.
Is this by design?
Can I try the serial RX? Are you defining a series of command we can send to manipulate the tester?
Mauro
Hi Mauro!
In the mean time I've noticed another small issue, possibly related to this bug:
If I try to measure a 3 pin component that happen to be a dead short, instead of measuring it as 2 small resistors, it enters the menu.
Is this by design?
Yes, it's a feature, not a bug
Originally this was the only way to enter the menu before we added the option to enter the menu also by the test push button. And the self test and self adjustment require shorted probes anyway. But I agree, it can be confusing in some cases. Maybe it's time to remove this feature. What do you and other users think about this?
Can I try the serial RX? Are you defining a series of command we can send to manipulate the tester?
At the moment the tester simply echos the serial input back to the PC while managing a small receive buffer. The next step is to figure out what kind of commands would be useful for automation. Any suggestions are welcome.
PS: the results of the optocoupler check will be put out via the serial interface too
Cheers,
Markus
Make sense
, but I can't speak for others because I enter the menu only rotating the encoder and dunno what this will impact on the testers with just the botton.
Regarding the serial output, at the moment I'm using it (with the k-firmware) to replicate the display content on a desktop monitor and with a bit of parsing to log each measure. This is part of a super easy test jig at work and I can say that it was good to have all the content of the LCD always also logged (identify human errors...).
It should be also useful to start a measure or a enter in a menu with a command and get the result also on the serial output.
In this case I think it should be better to select if we want a single measure or a continues cycle.
Just my 2 cents
Mauro
BTW As always...Thank you so much
Hi All, first post.
Sorry if this post sounds daft but I'm a rank amateur with this stuff (I'm just looking to test some germanium transistors for guitar pedals).
I just ordered a GM328A off ebay and I received it today. I have tried powering it up with both a 9v battery and a power supply. When I press the rotary button nothing happens, no LED lights, the screen doesn't turn on. Is there some sort of rain dance I need to do before the unit works or do I just have a faulty unit?
This is the unit I bought
https://bit.ly/2pzHQI3.
Welcome! I like the idea of the rain dance but your tester seems to be simply DOA.
Hi All, first post.
Sorry if this post sounds daft but I'm a rank amateur with this stuff (I'm just looking to test some germanium transistors for guitar pedals).
I just ordered a GM328A off ebay and I received it today. I have tried powering it up with both a 9v battery and a power supply. When I press the rotary button nothing happens, no LED lights, the screen doesn't turn on. Is there some sort of rain dance I need to do before the unit works or do I just have a faulty unit?
This is the unit I bought https://bit.ly/2pzHQI3.
Program the 328 thing then redo the rain dance
Envoyé de mon iPad en utilisant Tapatalk
The next step is to figure out what kind of commands would be useful for automation. Any suggestions are welcome.
Having some SCPI-like commands would be great. "READ" for numerical data, "COMP" for component and "UNIT" for
unit of measurement would be nice to start with.
I did write some Profilab programs for the GM 328 Transistor tester. But since formatting is different for each component
and dependent on the type of display, I had to write a separate program for each component.
Because formatting is also dependent on the specific firmware, keeping the programs up to date for the GM 328
alone is tedious (and boring). Thus having a few commands would simplify programming very much so that I
would be prepared to resume Profilab programming for the Transistor Tester - regardless of type.
Hi All, first post.
Sorry if this post sounds daft but I'm a rank amateur with this stuff (I'm just looking to test some germanium transistors for guitar pedals).
I just ordered a GM328A off ebay and I received it today. I have tried powering it up with both a 9v battery and a power supply. When I press the rotary button nothing happens, no LED lights, the screen doesn't turn on. Is there some sort of rain dance I need to do before the unit works or do I just have a faulty unit?
This is the unit I bought https://bit.ly/2pzHQI3.
Program the 328 thing then redo the rain dance
Envoyé de mon iPad en utilisant Tapatalk
Thanks perieanuo but how do I program it? Is there any instructions for this online?
Scan back a few pages. Instructions for programming the more common versions are repeated in this thread from time to time.
I wanted to report back to everyone. Thank you again to everyone for their help!
I have been able to compile 1.32m for a while, but was having trouble with the tester itself. The scope showed nothing revealing even with the solder points. Still didn't work correctly.
I have been messing around with it and decided to try a different programmer. I got an Adafruit USBtiny. I sent it the firmware and it worked the first time!
For whatever reason, the Atmel-Ice would just not program the 328p reliably on my Mac. But, the Adafruit worked right off the bat!
Perhaps it was an issue with AVRdude, but I'm not going to question it. Everything appears to be working!
I don't know why it was showing a sine wave either.
Enjoy the oscilloscope. If you see a sine wave, and it's 60 Hz, then you're seeing inductive (or capacitive, but probably inductive) coupling into your probe. Mains AC couples into everything. This showing up on your scope is a consequence of its very high input impedance.
at 7V P-P? Pretty strong for induction isn't it?
I have spent a few hours attempting to search for answer but seem to be overlooking it.
I read that not all of these mega328 lcr testers are capable of using the M-Firmware? Is there a way to determine which variants of this tool support the M-Firmware? Or is there a most popular variant of this device, I havent had success finding it in these pages.
Thanks for your time!
Most clones are supported by both firmwares (k & m). As long as the circuit follows the basic design it should work fine. One problematic clone is the TC-1 which uses an additional MCU for power control and test button. That hasn't be reversed engineered yet.