Products > Test Equipment
TC1 lcr-meter transistor-tester fix
madires:
You can run "make upload" after setting the programmer in the Makefile. And for the fuses it's "make fuses". Regarding U4 you can alternatively replace U4 with a simple two-transistor circuit (https://github.com/madires/Transistortester-Warehouse/blob/master/Hardware/TC1-Mod.kicad.tgz) which also has a lower quiescent current.
belzrebuth:
The STC-ISP managed to recognise the IC as STC15L104W but I still can't get it to upload the firmware.
I have my 6V8 diode removed from circuit while the DZ2 is installed.
Can this prevent the tester from working.
I only have a 6v8 zener in a thru hole package.
Can I install this one?
Does it need a high wattage (1W or so) or any 6V8 diode will work?
Sorry for all these questions madires, I really appreciate your help.
edit: I can't even re-recognise the IC when I try to "check MCU" from the STC software.
It did it once and I can't make it to repeat it.
So no wonder it can't upload the .hex file.
I need to power the DUT under a certain timing frame or something?
edit2:
To define what my problem is:
If I power the tester with 3.7V from my bench supply it starts up and measures components fine.
Power consumption is around 240mA when this is happening which I think is a bit excessive.
So I let cycle thru "Probing.." around 3 times and then it displays "Bye" and shuts off.
If I press the button I get about 200mA current consumption again but all I get is a white screen and then the tester shuts off.
What could be causing this behavior?
I need to mention that I put diode D0 backwards once I removed it to check it.
I powered up the unit one or two times with that diode placed backwards, I hope I haven't managed to destroy my 2nd atmega.
belzrebuth:
@madires
Do you have a picture or something of your TC-1 U4 replacement mod?
I did download it but it's kicad files which can't be opened with Eagle and I can't open it with Kicad either cause there are some libraries or footprints missing as it says.
I think I'm going to remove U4 as I can't seem to be able to program it or even check its status.
madires:
The Zener/TVS plus DZ2 are a weak overvoltage protection and can be removed without any problem. DZ2 is often damaged in case of a charged cap. 240 mA are much too high. So there's some bad component. The TC-1 mod archive includes three images.
belzrebuth:
I quickly bodged your replacement circuit in a small piece of proto and it worked :)
Current consumption is now 200mA or so when it's on, I find it a bit high as well.
But it also works with a semi-discharged battery so I guess it's okay now?!
What a typical current draw should be if external power is applied at the battery terminals?
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