Acoustic 370 resistor toaster.

[The Dude]

Generally, you can test a diode in circuit unless you read a short. It should read roughly the same as a transistor junction using diode check function (.6 or so forward biased). If you read a short, then unsolder one end of the diode and see if the short is caused by the diode or the circuit it is connected to. Of course if you get no voltage drop or a drop higher than .6 or so, the diode is likely open.

As far as terminology, 'Open' or 'Infinite' works for me. The reason Enzo brings this up is because "no reading" can be interpreted as a short or open. It is not clear to us what you mean and the two are exact opposites.

[ManRay]

Generally, you can test a diode in circuit unless you read a short. It should read roughly the same as a transistor junction (.6 or so). If you read a short, then unsolder one end of the diode and see if the short is caused by the diode or the circuit it is connected to.

As far as terminology, 'Open' or 'Infinite' works for me. The reason Enzo brings this up is because "no reading" can be interpreted as a short or open. It is not clear to us what you mean and the two are exact opposites.

All of the diodes in the power section are reading between 600-1000 on the diode function of the meter, except CR309 which is only reading 5. Does that mean that the diode is bad? What function does that diode serve in the circuit and does that reading make sense given the rest of the information I have?

[The Dude]

If you look at the schematic, CR309 is paralleled with R324, which is a 1 ohm resistor. The diode is likely ok and you are measuring across the resistor. But, as I said previously, if you read something unexpected, it's best to unsolder one side and check out of circuit.

[g1]

like 5 or 005?
It seems odd that a meter would read 300, 700, etc. but then 5, 3, 7 ?
Usually there is a decimal place before the digits (.700) but not always.
Can you be more exact in your description?