Taylor 45C Valve Tester

[Radfordman]

I recently purchased a Taylor 45C, but, unfortunately it has a problem that I can't resolve. Namely, on mutual conductance testing I can adjust pot A to "X" position but I am unable to adjust the meter back down to "0" with pot B, I am only able to adjust it to the centre of the meter. I have tested all the resistors, diodes, caps and replaced any out of spec. resistors.

Has anyone had the same problem?

Can anyone help me?

Thanks Trevor

[MichaelR]

Hi Trevor,

Have you checked the small fuse in the fuseholder on the top of the unit. This may have blown.

Finally check all of the wiring to make sure nothing has broken away from a joint . The wiring on these units is excellent but sometimes when previous owners may have been inside mesing about they may have dislodged a wire connection.

Regards
Mike

[igranic]

Trevor,

Check the bridge rectifier which feeds either end of the 'B' potentiometer. Early versions of the 45c used a selenium bridge rectifier, later versions featured four germanium diodes wired in bridge formation. A failure here would display the symptoms you describe.

Incidentally, it would be enormously helpful if you could respond to this thread with a copy of the Valve Base Wiring Chart from page 4 of your 45c manual along with the serial number; the circuit diagram is not needed.

Also, if you have any addenda or update sheets for the 45c, I would be really grateful for copies. If you need my email address, please send me a PM.

Edward

[Radfordman]

Originally Posted by MichaelR

Hi Trevor,

Have you checked the small fuse in the fuseholder on the top of the unit. This may have blown.

Finally check all of the wiring to make sure nothing has broken away from a joint . The wiring on these units is excellent but sometimes when previous owners may have been inside mesing about they may have dislodged a wire connection.

Regards
Mike

Thanks very much Mike for your quick reply, I am undertaking your advice.

Regards Trevor