kpearsall
Well-known member
Here's a fun one for you guys :
Working on an Ampex 351 with an intense crackling happening. Seems loudest between pins 3 & 8 on 12au7 output tube. Worked it out to an apparent open connection between the center tap and blue primary wire on the output transformer. Trying to really verify this before money is spent on a new transformer. If I disconnect the blue wire from circuit though, I'm still measuring voltage on it. Same voltage as on the brown primary and CT. If I disconnect the brown primary and leave the blue one connected, Then the red CT measures 125VDC instead of 440 as it does with the brown primary connected. I'll try to attach a schematic.
Any guidance greatly appreciated.
Working on an Ampex 351 with an intense crackling happening. Seems loudest between pins 3 & 8 on 12au7 output tube. Worked it out to an apparent open connection between the center tap and blue primary wire on the output transformer. Trying to really verify this before money is spent on a new transformer. If I disconnect the blue wire from circuit though, I'm still measuring voltage on it. Same voltage as on the brown primary and CT. If I disconnect the brown primary and leave the blue one connected, Then the red CT measures 125VDC instead of 440 as it does with the brown primary connected. I'll try to attach a schematic.
Any guidance greatly appreciated.