Quote:
Originally Posted by DMcMahon
Yes a Happy New year to you also, more importantly a happier one, hopefully from all aspects.
That is very disappointing for your Terry and frustrating.
Yes if the hum disappears/reduces a lot with the volume control wound down then would point to EF86 area (assuming R6 is the volume control). Check the control grid of V2A (ECC81 pin 2) with the volume control fully wound up in Playback to see if any DC voltage is getting through the coupling capacitor C4. Also check the EF86 voltages at the anode (pin 6), cathode (pin 3) and suppressor Grid (pin 1) to make sure their voltages are similar to schematic values.
For bad anode voltage check R3, for bad suppressor grid check R4/C2/C3, for bad cathode check R3/C3.
If voltages cannot be safely checked then would recommend replacing C4/C2/C3.
David
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Voltages at pins 1 and 3 are spot on, voltage at pin 6 is 90v just under the 100v on schematic. No voltage getting through C4.