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Re: Need help finding a schematic for a Quasar TV/VCR combo

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

  1. 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 from
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and > from
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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. 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.
Reply to
mikeydude
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On Tue, 29 Mar 2005 18:25:38 GMT, "mikeydude" put finger to keyboard and composed:

Yes, you're right. Sorry, brain fart.

It seems that you may be lucky and that your regulator has survived. Perhaps R802 protected it. I'd be checking the load (HOT, FBT) for shorts.

- Franc Zabkar

--
Please remove one 's' from my address when replying by email.
Reply to
Franc Zabkar

I will check the load.

Thanks, Franc! And thanks to all who helped!

-Mike

Reply to
mikeydude

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