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Untitled

December 1 2006 at 9:58 AM
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chris  (no login)

i have a 27" Curtis Mathes CM27101s chassis # CN-011
Shorted HOT Q402. removed Q402 and reading about 1.2 ohms from the collector point to ground. should be higher all components seem to check good need help on thisb one to save time

 
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Anonymous
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Re: Untitled

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December 1 2006, 12:35 PM 

?

 
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(Login U269)

Re: Untitled

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December 1 2006, 3:52 PM 

Testing with a (Analog) VOM
For NPN transistors, lead "A" is black and lead "B" is red; for PNP transistors, lead "A" is red and lead "B" is black (NOTE: this is the standard polarity for resistance but many multi-meters have the colors reversed since this makes the internal circuitry easier to design; if the readings don't jive this way, switch the leads and try it again). Start with lead "A" of your multi-meter on the base and lead "B" on the emitter. You should get a reasonable low resistance reading. Depending on scale, this could be anywhere from 100 ohms to several K. The actual value is not critical as long as it is similar to the reading you got with your 'known good diode test', above. All Silicon devices will produce somewhat similar readings and all Germanium devices will result in similar but lower resistance readings.
Now move lead "B" to the collector. You should get nearly the same reading. Now try the other 4 combinations and you should get a reading of infinite Ohms (open circuit). If any of these resistances is wrong, replace the transistor. Only 2 of the 6 possible combinations should show a low resistance; none of the resistances should be near 0 Ohms (shorted).

As noted above, some types of devices include built in diodes or resistors which can confuse these measurements

 
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Anonymous
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Re: Untitled

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December 1 2006, 4:22 PM 

that message was copied from a book. how do i know? because the spelling was to good to be Frank's. Ganges Man

 
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(Login U269)

Re: Untitled

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December 1 2006, 5:53 PM 

You don't answer to my posts because i don't know to write very well?

 
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Anonymous
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Re: Untitled

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December 1 2006, 6:05 PM 

But ain't I right?

 
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