Question about resistance check

FrancoB · 3624

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Offline FrancoB

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on: August 05, 2010, 04:12:59 AM
On terminal 13 the manual states that it should slowly climb to 270K.

In my situation it slowly descends to 270K.

What's going on here?

The rest of the checks are OK. Many thanks for your help!



Offline FrancoB

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Reply #1 on: August 05, 2010, 09:25:01 AM
OK. This happened only the first time. Still don't know what went wrong there.




Offline Grainger49

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Reply #2 on: August 05, 2010, 10:18:50 AM
If you do a resistance check it charges the capacitor.  If you then reverse the leads it starts at infinity or somewhere there about and comes down to the final resistance.



Offline Paul Birkeland

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Reply #3 on: August 07, 2010, 05:25:32 PM
Hello Franco,

Different meters behave differently when measuring a resistor with a capacitor across it.  The big jist of those measurements is that you have high resistance from B+ to ground (across the capacitor).  If you saw something between 0 and 10,000, that would be concerning (short).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline druelle

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Reply #4 on: August 17, 2010, 02:35:39 PM
I also have a question regarding the resistance check. When checking the terminals that should read 2.9K ohm, I read exactly 3.00K ohm. Should this be a concern or is within the normal variation?

Thanks in advance.



Offline JC

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Reply #5 on: August 17, 2010, 03:09:13 PM
I think that you will find that the reading you describe is well within tolerance.  Even at a tolerance of + or - 5%, you would be allowed a deviation of ~145 Ohms either way, and I would be surprised if Bottlehead is specifying a tolerance that tight on resistance checks.

Jim C.