I bought a variant of this product recently, mostly to measure transistor gain. I've measured several 2n3094 and 2n3096 components, and they all measure hFE ~ 370. If I'm reading the datasheets right, it shouldn't exceed 300 (and usually be much lower).
https://www.amazon.com/Mega328-Digital-Transistor-Resistance-Capacitance/dp/B07WT9VVZB#customerReviews
Am I missing something? I saw that there can be measurement errors for leaky parts (germanium), but haven't seen complaints about common Si parts.
If you buy a DIP version, you have better chance of getting a real 328.but what is the difference between DIP and non DIP versions?(Besides one being rectangular and larger whereas the other square and smaller), as we have been discussing on this thread, it seems the knock-off MCUs are being manufactured on small square encapsulations (cheaper), so that's why some of us think if you look for a DIP28 ATmega328P-PU, and if the vendor photo it's accurate, you have chances of obtaining a read one (with 32KB of flash, of course).There is still the problem that an ATMega328 can't run a full feature firmware and its low accuracy. Given the low price of the controller, I am wondering if I could just replace the bundled ATMega328 with an ATMega1284 and flash it with the related firmware.If you have a real ATmega, you can evaluate what changes you could make. Or, if you have an LGT8F328P-based unit, and you have a real ATmega, you could adjust the pinout and make the replacement.
If someone can post some documentation source I would really appreciate. The PCB photo shows a non existent link to https://www.mikrocontroller.net/svnbrowser/transistortester/ and I'm wondering if this is a dead project. The firmware is heavily customized and I have read somewhere it is private. I am concerned about updates given the fact that the official ones regularly published will not work for sure.kubi48, madires, and indman have posted documentation on different sites. madires has gathered many of that (including an overview I composed) at github.
Many thanks for your help. I will ensure to follow these guidelines if I will end up with a clone.
Thanks, the link helped me a lot. I have read all the stuff included the faqs and now I have a better idea on how things work.
Feliciano, you have become the “lucky” owner of another FNIRSI product, congratulations!
to be honest, I wouldn’t waste my time on this.
My thoughts on finalizing this miracle of Chinese thought:
1. Remove STC and forget about it!
2. Try to improve the circuit
3. Check the assignment of the display contacts to the microcontroller, as they may also differ from the standard ones.
Continuing with my WIP clone, I found a major issue with one of the latest m324pa transformerless TC1 clones, limiting the OSHW mod posibilities: the manufacturer modified the push button behaviour so is no longer directly connected to the STC, but between two(three) transistors, where the power_lock is no longer triggered by the STC but from the ATmega itself (pin16 high on my m324pa), and the push button sends a low on pin42 of my m324pa. Therefore, the known "two vanilla transistors mod" to flash OSHW firmware is no longer valid for this model.
So, I rather invest some time on this unit than putting it aside or thowing it away. But to convert this schematic to the original one it's not feasible, as the changes are too many. Therefore if @madires and you and other readers can please support this new mod, I will appreciate it, and I think it will be of benefit for other "lucky" owners too.
I think you can simply ignore the STC of your TC1 variant, i.e. no need for the mod. Or remove it, as indman suggested.
the press of the button is detected by a low on pin 42, answered with a high on pin 16 to trigger the boosters.
All what we need might be just the pin assignment of the ATmega324 to configure the firmware accordingly.
carl1961, This is exactly the nuance I wanted to clarify with you.
The use of an additional microcontroller, which acts as a command translator for BGR displays as well as for the 8-bit paralell display that is installed in your clone version, does not allow full operation at a frequency of 16 MHz.
For whom this frequency factor is important, you should refrain from purchasing such GM328A models or find and connect a standard classic RGB SPI ST7735 display directly to the ATMega328 ports without an extra chip.
Just received this one, with original ATmega328P. They are still out there...Many thanks for the link. It seems to be a version of the GM328A different from the ones showed in the comparison chart. Isn't "M328Kit+TFT(AY-AT)" a better choice?