Hi guys,
I've been looking for a Hiland M644 everywhere for some time - including here, with a post on the Buy/Sell/Wanted board.
On aliexpress the Hiland when available goes for almost 40 euro, with the risk that what is received is not at all what it's advertised. Having already lost 35 Euro, including the 13 Euro to the last T7 debacle, the whole point of "cheap" is moot - now it is actually preferable to spend 50-60 Euro in parts and a JLCPCB sourced board to be at least able to have a perfectly working higher end device, rather than throwing literally away money out the window... like i just did with the two dud testers I got chasing the white herring of a M644.
At this point, the option of actually drafting on diptrace a PCB becomes a sort of necessity if I want a real, certified Atmega644 inside.
.... Problem is I tried to search info on the Atmega644 based transistor tester and there is LOTS. In reality, even overwhelming.
Karl-Heinz's 1.13K manual covers a Atmega644 schematic, with many add-ons, including a relay based protection - But, no definite PCB design.
In the repository, the only PCB available is a discrete, thru hole developer kit design without LCD, built around the DIP version of the MCU - and I have a few M644 but in the smt TQFP 44 package.
The most approachable and sensible thing to do could be to use as a basis the Hiland TT-M644 schematic, and either try to loosely redraft (reverse engineer) the PCB following the pictures posted, or try to design a completely new layout...
I can do the grunt work - I can use Diptrace, but a few things are a bit out of my league. Can anyone help me, at least providing an updated schematic based on the Hiland M644 that includes all improvements and corrections discussed here since the introduction of the Hiland a few years back (including the apparently missing Measuring ports protection), and maybe once I manage to actually produce something, check on the drafted design I did not do noob errors?
Once I have a definite design, I will make both diptrace and gerber files available to everyone here! It could become sort of a "reference" design.
Please help...