On 2025-08-19 10:04 p.m., organlists1--- via Jukebox-list wrote:
I'm a bit late to the party here....
I believe when you disconnect the loudspeaker plug, which is a EM (Electro-Magnetic), it will disconnect the B+ as the field coil is connected in series.
Don Resor
-----Original Message----- From: ascott822--- via Jukebox-list jukebox-list@lists.netlojix.com Sent: Tuesday, August 19, 2025 8:11 PM To: jukebox-list@lists.netlojix.com Cc: ascott822@aol.com Subject: [Jukebox-list] 780 fuse blowing issue
Still trying to chase down the reason the amp fuse blows. I replaced the 5Z3 tube for the chance that it might have a short as was suggested. That wasn’t the cause. I removed all plugs into the amp and made selections and as I replaced one at a time as a process of elimination. The fuse only blows when the speaker is plugged in. Any help please. Thanks, Allen
If the fuse only blows with the speaker is plugged in AND the 5Z3 tube is unplugged, but doesn't when the speaker not plugged in, then something about the speaker field coil is most likely the problem.
John :-#)#