Where to start... First, thanks for the post and the link to the datasheets. Second... the reply.
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The resistances in the application circuit are R802 = 2.2 ohm, R804 = 12K.
R802 is a power resistor with the value printed on it. 5.6 ohm, 3 watt. R804 is burned and unreadable, but it has a value of 11.36k ohms, so I replaced it with a 12k resistor after reading your post.
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Are you sure you have drawn R806 and R807 correctly? AFAICT, pin 1 should
connect to ground.
One side of R806 (220k) should connect directly to pin 2 of the regulator, the other side of the resistor is to ground. R807 is correctly drawn. It is a fairly low resistance (39 ohms). Pretty sure the value is correct. The colors read: orn/wht/blk/gold/wht.
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Before worrying about your resistors, I would test the regulator. Pins
> 2,3,4 are the B,C,E of an NPN Darlington pair. A DMM diode test should
> show two diode drops between pins 2 and 3, and between pins 2 and 4.
> Pins 3 and 4 should test open in one direction and as a diode in the
> reverse direction.
Testing between pins 2 & 3, it reads like a diode with the cathode on pin 3. This seems correct from what I see in the datasheet. Shouldn't this show up under test as a single base-collector junction? It looks like both collectors of the Darlington pair are connected. Testing between pins 3 & 4 also reads like a diode with the cathode on pin
- Seems ok. Testing between pins 2 & 4 reads like a diode, but with higher resistance. Consistant with a two diode drop, I would think.
Appreciate the help, -Mike
An STR30130 datasheet is available fromformatting linkand
> fromformatting link
>
> Before worrying about your resistors, I would test the regulator. Pins
> 2,3,4 are the B,C,E of an NPN Darlington pair. A DMM diode test should
> show two diode drops between pins 2 and 3, and between pins 2 and 4.
> Pins 3 and 4 should test open in one direction and as a diode in the
> reverse direction. The resistances in the application circuit are R802
> = 2.2 ohm, R804 = 12K.
>
> Are you sure you have drawn R806 and R807 correctly? AFAICT, pin 1
> should connect to ground.
>
>
> - Franc Zabkar
> --
> Please remove one 's' from my address when replying by email.