Hi,
I'm new to this site and was hoping to get some help.
I have a Fender Champion 110 and it would not become silent when the volume was turned all the way down. At first I thought this had to do with a bad connection to ground (later I found out I just needed to clean the pot). Anyways, I went in and noticed that somebody had already moved around the jacks. The joints looked kinda bad and I wasn't getting any continuity on the traces by the external speaker and output jacks. I was able to add some solder to the joints to gain continuity. Now the amp has a loud squeal. Kind of as if it were oscillation.
I tried reversing what I did. There was a hum from the amp and not the speaker. No sound from the speaker at all.
I checked the 1n4003 diodes and they were okay.
There's no solder jumping across the traces either.
If anyone can offer help that'd be great. Any pictures of the traces by the jacks would be helpful too.
Thanks!
I'm new to this site and was hoping to get some help.
I have a Fender Champion 110 and it would not become silent when the volume was turned all the way down. At first I thought this had to do with a bad connection to ground (later I found out I just needed to clean the pot). Anyways, I went in and noticed that somebody had already moved around the jacks. The joints looked kinda bad and I wasn't getting any continuity on the traces by the external speaker and output jacks. I was able to add some solder to the joints to gain continuity. Now the amp has a loud squeal. Kind of as if it were oscillation.
I tried reversing what I did. There was a hum from the amp and not the speaker. No sound from the speaker at all.
I checked the 1n4003 diodes and they were okay.
There's no solder jumping across the traces either.
If anyone can offer help that'd be great. Any pictures of the traces by the jacks would be helpful too.
Thanks!
Since this is an instrument amplifier I have moved it to the appropriate forum.
Check all connections , is a solid state design , schematic attached.
I will remove for test R55 - 47k , now output stage is isolated from the rest , still squealing? if Yes , is something about power section , maybe the Ic or feedback and zobel network.
If Not squealing , try injecting signal at C33 , or simply touch the negative terminal of C33 , if you hear HUMMMM is ok
http://music-electronics-forum.com/attachments/12401d1295307595-fender-champion-110-c.gif
I will remove for test R55 - 47k , now output stage is isolated from the rest , still squealing? if Yes , is something about power section , maybe the Ic or feedback and zobel network.
If Not squealing , try injecting signal at C33 , or simply touch the negative terminal of C33 , if you hear HUMMMM is ok
http://music-electronics-forum.com/attachments/12401d1295307595-fender-champion-110-c.gif
Thanks for the reply. And the schematic! I couldn't find it anywhere.
As I was looking over the circuit board I noticed that their was a bit of solder connecting one of the capacitors to both ends of a resistor near the input. I must have spilled a little but when I cleaned it up it worked fine. The volume just doesn't turn down all the way so I was thinking I'd try replacing the pot.
I do have a question though. How exactly do I inject signal into C33 or "touch" it?
Thanks again!
As I was looking over the circuit board I noticed that their was a bit of solder connecting one of the capacitors to both ends of a resistor near the input. I must have spilled a little but when I cleaned it up it worked fine. The volume just doesn't turn down all the way so I was thinking I'd try replacing the pot.
I do have a question though. How exactly do I inject signal into C33 or "touch" it?
Thanks again!
If now amp work well (no more squeal and you can ear the guitar at output) , and the only issue now is about volume pot , just change the pot with a new one with same value...
You don't need this anymore , if amp works! Anyway , removing R55 isolates the ouput stage , so if you touch with a finger the negative lead C33 , is like you're putting a signal that your body receive and you must hear a sort of Hum at mains frequency. Or if you have a signal generator , an mp3 reader can work , you simply connect this as a source with common at GND of amp and signal to C33 ...
You don't need this anymore , if amp works! Anyway , removing R55 isolates the ouput stage , so if you touch with a finger the negative lead C33 , is like you're putting a signal that your body receive and you must hear a sort of Hum at mains frequency. Or if you have a signal generator , an mp3 reader can work , you simply connect this as a source with common at GND of amp and signal to C33 ...
Glad you got back to where you started.
As to the volume not going to zero. Is this really a problem? Or do you just object to it on some sort of principle? I mean, how often do you desire to play at zero volume?
The amp has a gain and a volume for the drive channel, and a volume for the normal channel. All three of those could be called volume control. SO which control has the issue? Two of the controls are in the feedback loops for op amps, and do not go to ground like a conventionakl voltage divider. Only the drive channel volume does that. SO those two to me would not be surprising if they left a litttle sound at minimum seting.
As to the volume not going to zero. Is this really a problem? Or do you just object to it on some sort of principle? I mean, how often do you desire to play at zero volume?
The amp has a gain and a volume for the drive channel, and a volume for the normal channel. All three of those could be called volume control. SO which control has the issue? Two of the controls are in the feedback loops for op amps, and do not go to ground like a conventionakl voltage divider. Only the drive channel volume does that. SO those two to me would not be surprising if they left a litttle sound at minimum seting.
Thanks for the information Tesla88! I'll replace that pot.
For Enzo:
I'm talking about the volume for the normal channel. Even when it is turned down to zero it is still REALLY loud. Almost like it's on 8 which is too loud for my jazz band and practice room. I ordered a new pot of the same value and when it comes in I'll try it out. Fortunately the drive and gain channel volume you mentioned work fine.
For Enzo:
I'm talking about the volume for the normal channel. Even when it is turned down to zero it is still REALLY loud. Almost like it's on 8 which is too loud for my jazz band and practice room. I ordered a new pot of the same value and when it comes in I'll try it out. Fortunately the drive and gain channel volume you mentioned work fine.
Did you ever find a solution . I have the same problem with my 110. TIA <docwolff@comcast.net>