Hello folks ,and thanks again for adding me. I am in the beginning stages of trying to revive a 40-180 for an old friend. His grandparents bought it new ,and I'm really hoping I can get it working for him. I have just started replacing ,caps , resistors. I was told I could use larger value electrolytics ,so I'm using 22uf.
I have a couple of questions here in the early stages.
#1: How can I safely remove the pushbutton ,and coil assemblies so I can access the components underneath?
#2: The OT on this unit really confuses me. I'm used to OTs on guitar amps. This one has primary wires ,but no secondary wires to the speaker. How does that work if I need a replacement?
Can you post a photo showing the wiring for the output transformer from beneath the chassis? You should have four wires going to the speaker - two from the transformer for the voice coil and two from the power supply for the field coil.
DaleHCook, There are only three wires ,and a ground I see on the OT. Two go to the power tube plates ,and the center goes to 16uf cap ,and the field coil according to the schematic.
(This post was last modified: 05-06-2023, 10:03 AM by gtrplayr1976.)
Actually, there are three insulated wires, a bare wire, and another bare wire which you may not see since it is soldered to the frame (side) of the audio output transformer (56).
The three insulated wires are the primary of the output transformer.
The bare wires (one you see, one you don't) are the secondary of the output transformer.
Thank you Ron. I thought it was just the one bare wire. (thought that was just a transformer ground) Would make more sense now. I thought I checked those ,and the both showed ground ,but I'll check again. I know the resistance reading on the primaries is low compared to what the schematic says ,but the leads are still soldered.
