Hi, All. It is the first time I post a thread. I have found a lot of information in this forum and appreciate all people that share knowledge and spend their time to help .
I bought a Fender “The Twin” red knobs for twelve or fifteen years ago and it has been in the same place (music studio) all time, I never move it out. I have used it for 3 or 4 hours each Saturday afternoon; However last 6 month I did not use it. and last week when I turned on I detect a hum on channel 2 and it increase when I increase the gain. This happened only when the guitar is connected.
Characteristics:
The amp has a foot switch (two buttons) connected to change channels 1-2 and turn on/off the reverb.
The impedance switch is set to 16 ohms (two 8 ohms speaker serial connected)
I do not have any effects connected.
The guitar that is connected is a 2 humbuckers Telecaster (The guitar and cable does not produce any noise when connected to another amp).
The hum is not noticed when the standby switch is off.
The channel 1 is clean.
Schematic is here: http://www.ampwares.com/schematics/the_twin.pdf
I put off the chassis and clean with a brush a few dirty I found in there.
I cleaned the potentiometers with a spray.
I revised solder points and I saw it good (brighter).
The wiring looks good.
I replaced the tubes V1 (12Ax7) and V2 (12AX7) with news ones and cleaned sockets of all 11 tubes.
I checked the resistors (with a digital multimeter) on board for this channel ; apparently are good.
I did not remove any capacitor until now.
But the problem persist…….
I will thank to anybody who can help me.
Thank you.
I bought a Fender “The Twin” red knobs for twelve or fifteen years ago and it has been in the same place (music studio) all time, I never move it out. I have used it for 3 or 4 hours each Saturday afternoon; However last 6 month I did not use it. and last week when I turned on I detect a hum on channel 2 and it increase when I increase the gain. This happened only when the guitar is connected.
Characteristics:
The amp has a foot switch (two buttons) connected to change channels 1-2 and turn on/off the reverb.
The impedance switch is set to 16 ohms (two 8 ohms speaker serial connected)
I do not have any effects connected.
The guitar that is connected is a 2 humbuckers Telecaster (The guitar and cable does not produce any noise when connected to another amp).
The hum is not noticed when the standby switch is off.
The channel 1 is clean.
Schematic is here: http://www.ampwares.com/schematics/the_twin.pdf
I put off the chassis and clean with a brush a few dirty I found in there.
I cleaned the potentiometers with a spray.
I revised solder points and I saw it good (brighter).
The wiring looks good.
I replaced the tubes V1 (12Ax7) and V2 (12AX7) with news ones and cleaned sockets of all 11 tubes.
I checked the resistors (with a digital multimeter) on board for this channel ; apparently are good.
I did not remove any capacitor until now.
But the problem persist…….
I will thank to anybody who can help me.
Thank you.
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