Re: Wacky voltage readings


Alan G4ZFQ
 

I show 19.91K from R2 to ground, and 9.96K for R1 plus 9.95K for R2.
C6 shows resistance across it of 9.96K, which it should since it parallels R1, so I do not identify a problem there. I get 3.98V at R2 on one side,

Charles,

I get 3.98V at R2 on one side,
It should be 5V on one end. What current is the CQX taking?
Looks like the centre of R1/2 is going to ground when IC4 is switching.
Check for shorts to ground on C43-C46 and the associated pins of IC4.

and nominally 0.15 volts on the other side. That is also what I show +/- 0.05V at the four points on T1 which is quite low for the published specification of ~2.36V. And I still have the following on IC-5, way out of spec:
Is it possible IC-4 is fried and that’s where the voltages or lack there of originate?
It is possible but more likely is a solder bridge.
Again, it is possible one of the capacitors is faulty.
Are the ICs correctly oriented?

73 Alan G4ZFQ

Join QRPLabs@groups.io to automatically receive all group messages.