Metlupass2
Well-known member
I just got this Cameron Aldrich JCM 2003x last week and it was fine no issues but today I decided to check and adjust the bias. I was only able to adjust to 32.5 mA even though they needed to be 39. 32.5 was the highest the pot would adjust.
Everything was fine then.
Then I removed the power and preamp tubes to clean the tube sockets with contact cleaner like I always do. I let it sit an hour before firing it back up.
All it did was hum quietly and the plate read 150 and the tube current wasn't even registering with my Eurotubes Pro One. The HT fuse was blown so I replaced it but amp did the same thing, quiet hum no output. I checked the fuse again and it's NOT blown.
I changed the preamp tubes and now it hums REALLY loud.
Look at how hot the one power tube gets right away. I swapped it with another and that other tube got hot in the same socket.
Everything was fine then.
Then I removed the power and preamp tubes to clean the tube sockets with contact cleaner like I always do. I let it sit an hour before firing it back up.
All it did was hum quietly and the plate read 150 and the tube current wasn't even registering with my Eurotubes Pro One. The HT fuse was blown so I replaced it but amp did the same thing, quiet hum no output. I checked the fuse again and it's NOT blown.
I changed the preamp tubes and now it hums REALLY loud.
Look at how hot the one power tube gets right away. I swapped it with another and that other tube got hot in the same socket.