Question: power tube issue
- pocaloc
- PAT. # 2.972.923
- Posts: 1729
- Joined: Tue Aug 04, 2009 2:40 pm
- Location: Spokane, WA
Question: power tube issue
I have a 15 watt el84 based amp, with two el84’s. The second el84, with one el84 between it and the rectifier tube, is not lighting up. I see it light up just a touch every so often. The other el84 and rectifier are lit up strongly. I’ve verified that it is not a tube problem. This happened before and the amp started working the next day. This time the problem hasn’t gone away. By the way, there is no sound to the amp, just an electric hum. Anyone have any idea what the issue could be? I looked into the guts and nothings looks bad. Thanks
- Witchburner
- PAT. # 2.972.923
- Posts: 59
- Joined: Fri Aug 18, 2017 12:09 pm
- Location: 71st
Re: Question: power tube issue
So one half of the inverter isn't working, or some how theres an opening in the circuit towards the respective tube thats not working, if its cutting in and out it could be an improper joint or the socket not seated properly
a lot of times there are components that seem fine but they aren't
check the schematic and see the bias point for each individual tube, check the voltages on the pins, and follow back from the tube with the probelm till you find a drop across or whatver it may be
This has to be done with the amp on, and if you fuck up you could die there are lethal voltages, keep one hand in your pocket while you do this
be careful
if you dont know what youre doing take it to a tech, i wouldnt play it anymore until it gets resolved you'll be waiting for that magic smoke to come out of the amp
a lot of times there are components that seem fine but they aren't
check the schematic and see the bias point for each individual tube, check the voltages on the pins, and follow back from the tube with the probelm till you find a drop across or whatver it may be
This has to be done with the amp on, and if you fuck up you could die there are lethal voltages, keep one hand in your pocket while you do this
be careful
if you dont know what youre doing take it to a tech, i wouldnt play it anymore until it gets resolved you'll be waiting for that magic smoke to come out of the amp
- pocaloc
- PAT. # 2.972.923
- Posts: 1729
- Joined: Tue Aug 04, 2009 2:40 pm
- Location: Spokane, WA
Re: Question: power tube issue
Hey thanks for responding. Just noticed. I took it to a tech last week. It only cost me $40 so no big deal. The heat pins? needed to have the solder re heated to get them to connect again in the second power tube position. All is good again.