Left channel went out

[dingwersen]

I Built my Stereomour about 3 years ago, no problems with the build, followed the directions step by step and with a little beginners luck (and some great direction) had a functioning amp. The only "problem" that I could see was a dead spot in the volume pot. This was a bit hi of my normal listening range so I chose to ignore it. I have been driving a pair of old Klipch Heresy's and my rather pedestrian ears have been quite happy.

One day I went for a listen and there was no sound from the left channel. An examination led me to find that the left tube had a foggy discoloration on the inside bottom, near the Bak-o-lite base of the tube. I figured the tube had "worn out" so I bought a new pair of the same brand and plugged them in and still no sound from the left channel.

I am a bit stumped, I'm not an "electronics guy" per-see, but I'm pretty handy and am fine with doing my own research, if someone could just point me in the right direction.

Thanks in advance,

Dan

[Grainger49]

The first step is to take the resistance measurements.  Take the tubes out.  Post any that are greater than +/- 15% from the manual.

If the resistance is good move on to the voltage measurements.  Tubes in.  Again post those outside the 15% range.

[Paul Birkeland]

An examination led me to find that the left tube had a foggy discoloration on the inside bottom, near the Bak-o-lite base of the tube.

If there was a white fog at the bottom, the tube lost its vacuum and is indeed dead.

If you're still missing a channel, I would start with a voltage check.

[dingwersen]

Thanks to both of you.

I am going to try the voltage test as suggested.

I recently moved and have yet to come across my manual. I may have to get another. I'll post back in a week or two once I have done a bit more reading and testing.

Thanks again,

Dan