D
Don
Guest
I have a Tenma 72-2075 regulated variable (0-30V) bench power supply
with digital display. I have checked it out to the best of my
abilities, but now I need some hints as what to do next. Here is what
has been tested:
- LED display lights up, all zeros displayed for both volts and
current
- Constant Current light is on
- unfortunately no smoked out parts
- power getting through transformer AOK
- power supply for power transistors AOK
- power supply for regulator circuit AOK
- power transistors tested out AOK
- it appears that no voltage is getting to the base of the power
transistors. This looks like it is fed from the regulator circuit. I
have the schematic (http://www.cameronsoftware.com/misc/72-2075schematic.pdf),
but it is a little beyond me to think of where to measure next. Any
pointers would be appreciated.
One other question: is there a web site or book that discuss how to
repair electronic equipment? It is one thing to understand
electronics, it is another to understand the method behind repair.
thanks
Don
with digital display. I have checked it out to the best of my
abilities, but now I need some hints as what to do next. Here is what
has been tested:
- LED display lights up, all zeros displayed for both volts and
current
- Constant Current light is on
- unfortunately no smoked out parts
- power getting through transformer AOK
- power supply for power transistors AOK
- power supply for regulator circuit AOK
- power transistors tested out AOK
- it appears that no voltage is getting to the base of the power
transistors. This looks like it is fed from the regulator circuit. I
have the schematic (http://www.cameronsoftware.com/misc/72-2075schematic.pdf),
but it is a little beyond me to think of where to measure next. Any
pointers would be appreciated.
One other question: is there a web site or book that discuss how to
repair electronic equipment? It is one thing to understand
electronics, it is another to understand the method behind repair.
thanks
Don