resistance check T15/T35 vs. T18/T38

[mete]

It writes all of these terminals should have 1.45K-1.55K. I measure T15/T35 as ~1.45K but T18/T38 as ~1.66K. I wired the output transformer for 4 ohms. Is that anormal ?

 

[Paul Birkeland]

That's consistent, T18/38 will be a little bit higher than T15/T35.

 

[mete]

200 ohm is the OT-2 primary resistance ?

 

[Paul Birkeland]

That is the resistance difference observed between those terminals, yes. What's important is that you don't see readings that are wildly different than what's specified (especially a zero where there isn't supposed to be).

 

[mete]

The problem is it is hard to guess what the not wildly different value or variance is (for all the tests). I dont know if there can be a better approach here, just saying from a user point of view. For some reason, if I see 22 ohm but I measure 21 ohm, I am not that much worried (I guess I am expecting a 5-10% difference by default for resistance), but if I see 1.45K-1.55K and I measure 1.6K it makes me unhappy. If that is a general feeling, it might be better to specify variance like in the voltage tests, rather than ranges. In the above case (T15-T18), I marked the terminals on the schematic, so I guessed T18/T38 should be T15/T35+OT-2 resistance and I was expecting an increase but I don't have a clear idea of what would be the OT-2 resistance seen there.

 

[Paul Birkeland]

In the paragraph before the resistance measurements, we note:
"Not all meters read exactly the same in certain conditions."

If you're not certain, you are certainly welcome to come here and ask about the resistances that your meter is reporting.