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Old 30th Apr 2009, 6:08 pm   #91
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Default Re: Roberts RT7 - problem

Quote:
R26 reads 2.53 ohms (20k test range both)
R27 reads .08 ohms
R26 and R27 are indeed the bias resistors. They form a potential divider across the battery. There should be about 8.8 Volts across R26 and 0.2 Volts across R27. By "across" I mean one meter lead connected to each end of the resistor. Thus with TR6 and TR7 in circuit you should see about 0.2 Volts on their bases. NOT 2 Volts.

What sort of meter are you using stonehopper? Is it an analogue one with a needle or a digital one with a digital display? I ask this question because I'm having some trouble interpreting your readings.

R26 should be 2.2K or 2.2 Kilo-ohms or 2200 ohms. You say it reads 2.53 ohms. If that's true it's about 1000 times off its true value. Could it in fact be measuring 2.53K or 2530 ohms?

R27 should be 51 ohms. You say it reads 0.08 ohms. Once again this indicates it's way off value. If however it's 0.08 Kilo-ohms that's the same as 80 ohms, which once again is way off value.

Regarding C32. Could you clarify what you mean by no reading. Do you mean Zero/0 ohms (short circuit) or infinite resistance (open circuit). You can replicate a short circuit by touching the meter leads together and an open circuit by holding them apart.
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