Transistor testing with digital multimeter

Thread Starter

Patrik Kubaska

Joined Feb 28, 2019
5
Hi everyone,
I consider myself to be a beginner in the field of electronics so the question might sound stupid to some of you.
Last night I was working on electronic heater/stirrer from a lab. The heater part is working but the problem is somewhere in the stirrer circuit.
I traced in my mind how everything is connected and came to a short on the circuit which I then traced to a BD675 Transistor. The short occurs between collector and emitter (removed the transistor from the circuit to be sure). When I connect my multimeter in diode mode to the collector and emitter it starts beeping continuously in both directions. Does that indicate a faulty transistor?

Datasheet: https://www.onsemi.com/pub/Collateral/BD675-D.PDF

Thank you ;)
 

ScottWang

Joined Aug 23, 2012
6,834
Could you post the circuit and all the details on circuit, it might help if the circuit have some bugs or somethings can be improved.
 

Thread Starter

Patrik Kubaska

Joined Feb 28, 2019
5
Thanks for the quick reply! I can post the circuit but it will take me a day or two to draw the complete schematic. The magnetic stirrer/heater is really old. They asked me if I can take a look at it so they don't have to stir the chemicals by hand in the lab. I will try to find a new BD675 or similar and see what happens. I tested everything else and there are no shorts or anything, only that one transistor. I took me few hours last night to trace everything from the output for the solenoids to the input (220v) and I found that short with the diode mode on the dmm so I took a closer look at the BD675 and removed it from the pcb to be 100% sure. Im still learning about electronics so I decided to ask someone to be sure that it is faulty ;)
 
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