Announcement

Collapse
No announcement yet.

Tubes or volume pot.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Tubes or volume pot.

    Hello my name is Randy thanks for the forum
    This is my first post. I found this place doing some reading and I liked it. It wonít allow me to complete my profile yet. But Iím
    In Fayetteville NC USA. Nice to meet all of you.

    Iím no amp tech by any means but I like to twinker around. I have a respect for powerful amps though anyways. I havenít had much luck finding a real tech so just wanted to see if I could get some opinions or ideas. Clues.

    The problem is ;
    Random Static noises but the jewel light dims and gets a bit of volume drop. But itís back to normal when I thump the warm Chanelís volume. Or it gets worse.

    And itís one of those things where you may think the amp is fine. But as soon as you leave and I start playing it will happen. Maybe I should try to catch it on video.

    It's on a peavey jsx 120 watt head by the way.
    It's Just sometimes not all the time I will hear static noises. And at the same time the light will dim. I keep my pots clean. And the light bulb is secure and tight. Hmm

    But this will happen when I'm not working the knobs. It's out of no where. Any suggestions on what it could I donít suspect the tubes but what do I know. Could this be a case where the amp has been dropped on the volume pot and itís loose at the board ? Maybe a drop of solder to repair.

    Well this has been like a minor annoying type of issue. It could be or turn into something major idk.

    Any comments ,jokes ,saying hello, anything would be greatly appreciated.

    I did read the rules real quick.
    I couldnít find a schematic but hereís a link ;
    https://www.thetubestore.com/lib/the...-Schematic.pdf
    Hope this is all good for now. Excuse me if I forgot anything

    Iíll come back and get my profile up to snuff as Iím allowed. Thank you so much for being here. RR

  • #2
    Open it up, pull each ribbon connector part way off then push is back down. This refresh the contacts. Well not just ribbons, ANY connector.
    Education is what you're left with after you have forgotten what you have learned.

    Comment


    • #3
      Originally posted by Rokinrandy View Post
      Hello my name is Randy thanks for the forum
      This is my first post. I found this place doing some reading and I liked it. It won’t allow me to complete my profile yet. But I’m
      In Fayetteville NC USA. Nice to meet all of you.

      I’m no amp tech by any means but I like to twinker around. I have a respect for powerful amps though anyways. I haven’t had much luck finding a real tech so just wanted to see if I could get some opinions or ideas. Clues.

      The problem is ;
      Random Static noises but the jewel light dims and gets a bit of volume drop. But it’s back to normal when I thump the warm Chanel’s volume. Or it gets worse.

      And it’s one of those things where you may think the amp is fine. But as soon as you leave and I start playing it will happen. Maybe I should try to catch it on video.

      It's on a peavey jsx 120 watt head by the way.
      It's Just sometimes not all the time I will hear static noises. And at the same time the light will dim. I keep my pots clean. And the light bulb is secure and tight. Hmm

      But this will happen when I'm not working the knobs. It's out of no where. Any suggestions on what it could I don’t suspect the tubes but what do I know. Could this be a case where the amp has been dropped on the volume pot and it’s loose at the board ? Maybe a drop of solder to repair.

      Well this has been like a minor annoying type of issue. It could be or turn into something major idk.

      Any comments ,jokes ,saying hello, anything would be greatly appreciated.

      I did read the rules real quick.
      I couldn’t find a schematic but here’s a link ;
      https://www.thetubestore.com/lib/the...-Schematic.pdf
      Hope this is all good for now. Excuse me if I forgot anything

      I’ll come back and get my profile up to snuff as I’m allowed. Thank you so much for being here. RR
      First let me start by saying you came to the right place and WELCOME to the board !

      The guys here are super knowledgeable in every way, a truly smart, experienced, and friendly crowd. I am a tinkerer just like you, with perhaps just a bit more experience on my 20 or so vintage amps.

      If you are getting crackling noises, and what seems by your description some sort of power drop outs, I would suspect a bad ground or bum solder joint somewhere.

      That's assuming when the amp is working normal, everything sound "A OK" for that time however short, until the dropouts happened and you lose volume and light dies or flickers. You mentioned that when you hit the channels volume it gets worse so that may be a clue to the area for the problem, from the vibration you are introducing.

      The first thing I would do is : Not only clean all the pots, but also clean all the sockets and switches with DeOxit or similar electronic cleaner, and make sure all the pins on your tubes are all straight when you pull them out (have a look). The pins don't have to be super shiny and like new for good conductivity, but the generally need to be pretty straight. That's an easy process and check. Spray the socket receiving pins with contact cleaner and put the tube in and pull it out a couple of times. Do that for all the tubes.


      That might fix it ! or perhaps not. But that whole exercise should only take 10 - 15 minutes tops, so it's an easy first step and might work, and you will start with everything not soldered having a clean contact.

      Then if you still have problems, take out the chassis and first look over all the circuits carefully to see if anything is burnt looking or obviously lose or broken. (Watch out for those potentially HIGH KILLING LEATHAL VOLTAGES !!!), and then use a wooden chopstick or a plastic non-conductive chop stick to check all your solder joints for any crackles with the amp running, and see if you can invoke the problem by pushing and tapping on every solder joint and listen for a crackle or dropout. That again shouldn't take more than 30 - 45 minutes and quite often you will find the exact spot with the issue, or at least the area where the bad ground or solder joint is, and you can re-flow the solder and fix it. Do this for every joint, ground, and Potentiometer connection. It's easy and quick, Just be safe and stay away from the high and lethal voltages by using only a Non-conductive stick !

      I've "Fixed" several of my vintage amps with similar "cat and mouse" dropouts and crackling like this, with going no further than cleaning and perhaps a re-solder of a joint or two. It could be something else, but start with the basics is my motto.

      Remember, Grounds have to be good, solder joints have to be solid, socket pins have to have tight tension, and tube pins need to be fairly straight. Over time things can become oxidized and connections bad, particularly if they were a bit improper when the amp was first born, or roughed up during it's life, but you can isolate it if you approach systematically.

      Ask any questions you like here, these guys have helped me dozens of times, and I've never had an issue that I couldn't resolve with this excellent team backing me up. If you don't give up, they wont, that I can tell you !!!
      Last edited by HaroldBrooks; 04-28-2020, 09:39 AM.
      " Things change, not always for the better. " - Leo_Gnardo

      Comment

      Working...
      X