Topics

Help with T1 voltage differences.

Albert Rowe
 

Hi, Excuse my ignorance but I'm not good with the theory side of the kit, I have tested the voltages on T1 using the on-board voltage tester, the desired voltage on points 5,6,7,8  is 2.36v, my reading is 0 at points 1,2,3,4 and 1.46v points at 5,6,7,8, what factor alters this voltage value please?.

Alan G4ZFQ
 

1.46v points at 5,6,7,8, what factor alters this voltage value please?.
This comes from the potential divider R1/R2.
Have you 5V at R2 opposite end? Are they both 10K? Resistors and T1 soldered well?
It is possible that something at the switch outputs of IC4 might affect this, what are the voltages across C43, 44, 45, 46?

73 Alan G4ZFQ

Albert Rowe
 

Hi Alan thanks for the reply, I did leave a list of all suggested voltage points the other day with the pictures I uploaded but not sure if they came up, voltages C43, 1.40v, C44 1.83v, C45, 1.71v, C46, 1.50v R2 voltage (wire end) 4.7v, board end 1.8v, Colour code Brown Black Black Red Brown checked with DVM before installation, I have checked T! Several times (each separate winding!), just discovered point 4 centre is making contact with point 2, I assume the coating is damaged somewhere. I will rewind and try again, I had to add 2 turns at point 1 end to achieve the required setting of C1, thanks again.

N3MNT
 

Before you pull T1 and rewind it, check the schematic.  Once installed on the board, the windings will not all show as separate.

Albert Rowe
 

Hi Thanks for that, I wound it as 4 individual windings with the required inner legs pointing straight down and cut in 3 steps so as I lowered it onto the board they each in turn went into their required holes, then the outer ones the same after which I pulled them down to lower the toroid to the boards (having burned and sanded beforehand of course). So assumed they would be individual windings which is how they look to me on the schematic!.

N3MNT
 

They are individual windings, but some of the legs are connected to common points. so the other ends may appear to be connected ( through winding) once soldered to board.

Albert Rowe
 

Understood, thanks again.