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TC1 lcr-meter transistor-tester fix

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belzrebuth:
Thanks for your reply madires.Really appreciate your help.
I get about 21.5V where I should be getting about 37.. (D2)
How should I enable the DC converter manually?!

I noticed that if I connect my bench PSU to the battery terminals providing 3.7V if I press the button I get about 0.35A current draw and then after a short period of time almost no current draw(0.9mA) or so.
Forgot to mention that I get about 3.4V at the 5V regulator input and 1.7V at it's output.
The regulator input and the 35V rail which is 21.5 maybe tell that the DC-DC converter might be faulty?!
I also get about 25ohms between the 5V rail and ground which seems low but then again the meter boots when I give it 5V and it's current draw is not excessive.




madires:
If the boost controller is an AL693 pull up pin 4 (to the battery's voltage). That pin is connected to a pull-down resistor and pin 3 of U4.

belzrebuth:
The marking of U5 is AL715..

madires:
No idea about that one, but I'd guess it's quite similar.

belzrebuth:
Nothing changed when I pulled the pin4 to 3.7V.
Same input to the regulator.
If nothing else down the line is preventing the 9 or so volts to appear maybe the DC/DC is bad.

Maybe I should just buy this IC and replace it, as long as it exists somewhere which I'm not sure of.
Seems like a non-standard part available in China only.

If I power the thing with 5V directly shouldn't it measure components though?
I mean if my MCU is also bad (which btw is an ATMEGA 644 not 324) I could just buy a new meter and discard this..
Are the capacitors I've removed critical to the operation when powered directly from 5V?

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