Lonestar Classic Lead Channel Problem

[Janglin_Jack]

I was at practice tonight and realized at one point I couldn't hear my guitar. I fiddled with some cables, etc and then discovered that the lead channel, would start out audible and then within 2-3 seconds, the volume just disappeared. I could switch to the clean channel and use pedals, but for some reason when I switch to the lead channel, You can hear the guitar for a few seconds and then it goes silent.

What can cause that type of failure??

Jack

 

[knightkw]

Do you have the loop active or on bypass? And are any cables plugged into the loop jacks? Check out the thread in my post titled Lonestar Problem - no output. The problem you mention could be a bad preamp tube, but it may just be a dirty return jack for the loop.

 

[Janglin_Jack]

Loop is bypassed and no cables. I change a cathode bypass cap a while back, mayube it has come loose.

Any other ideas?

Jack

 

[BottyGuy]

Do you run the clean channel and 100W lead channel at 50W and have Rectifier tracking enabled?

Then it could be a bad Rectifier Tube, try setting the rectifier to "Diodes" if the problem goes away buy a new tube.

 

[kramerxxx]

My guess would be a preamp tube, probably V2.

 

[JAZZGEAR]

"Then it could be a bad Rectifier Tube, try setting the rectifier to "Diodes" if the problem goes away buy a new tube."

No, you wouldn't get any output at all if it were the Rec tube....the poster stated that there would be output initially then it would fade away. :wink:

 

[Janglin_Jack]

I am going to pull the chassis and check the Cathode Bypass Cap that I changed, (most likely the problem). I will resolder and be sure there is good contact. Then I will check the preamp tube and then the rectifier.

Thanks for the suggestions.

Jack

 

[Janglin_Jack]

Since I modified the cathode bypass cap, I was certain that is what it was. So I pulled the chassis and checked the solder joints. They looked fine, but I reheated them anyway. Put the chassis back and same problem. So I switched the rectifier to diodes, (as I was using 50w and tube rectified). That is what the problem was, bad rectifier tube.

That will teach me to check the easy stuff first. I could have saved about 15 min by flipping the switch. Good to know my soldering is better than I thought!!

Thanks guys,
Jack

 

[BottyGuy]

Glad to hear its fixed, by the way, the fading out should have been a dead give away. Once you switched to the drive channel and the diodes were switched out it took a couple seconds for the B+ voltage to leak away. I'm gonna etch that into my memory.