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Thread: Great learning site: Mr. Carlson's Lab

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    Senior Member Mars Amp Repair's Avatar
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    Great learning site: Mr. Carlson's Lab

    For newbies and even some of us 'Seasoned' techs. He covers a great variety of important tube amp tricks and concepts just repairing and modifying this signal tracer.
    Search YouTube: 'Electronic Repair Adventure- 'The Signal Tracer'. Mr. Carlson's Lab.
    He also rebuilds a Fender 135W combo amp from a technical standpoint although he's not a musician and does it from a non-musician standpoint. (I haven't watched that one yet).
    He does alk this in a very understandable-down-to-earth manner. Glen

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    Supporting Member TomCarlos's Avatar
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    Thanks for the post. The video collection looks interesting!!

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    Stray Cap DrGonz78's Avatar
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    One his latest videos that I watched from him was about checking out an old generator. Since he lives in Canada and the power went out in the past. So just like MEF we get all variety of repairs. Just don't follow his advice by removing surface mount caps by twisting them real quick with needle nose pliers. I am sure it works but if you accidentally rip off the solder pads, that would suck.

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    When the going gets weird... The weird turn pro!

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    Senior Member Mars Amp Repair's Avatar
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    Quote Originally Posted by DrGonz78 View Post
    One his latest videos that I watched from him was about checking out an old generator. Since he lives in Canada and the power went out in the past. So just like MEF we get all variety of repairs. Just don't follow his advice by removing surface mount caps by twisting them real quick with needle nose pliers. I am sure it works but if you accidentally rip off the solder pads, that would suck.
    Yes, I agree. I probably wouldn't use that method, either! What I do might make someone else cringe, too. Rock the cap from side to side until you remove the cap sans the leads which remain soldered to the pdb for easier removal.
    Anyway, his videos are always informative & as always we use our own judgement with our own experience as to our personal take-away.
    I thought all the tube amp mods & tricks & just general info he shared on that audio signal tracer video is more than you'd ever find in one video anywhere else & so succinctly & simply explained. Of course you could ferret out all that information & more by searching this site as many of the techs are well seasoned & super knowledgeable, but it would take time. I we were just starting out, this was very powerfully packed with great information:
    1) Proximity of power transformer to audio output transformer (I've turned reverb tanks 180 deg similar reason) 2) How to find best star ground (which I've personally done with a signal tracer like this one) 3) power supply filtering basically explained 4) Filament hum balance circuit...and there's probably more I'm forgetting.
    Thanx for all the comments...glen

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    Quote Originally Posted by DrGonz78 View Post
    One his latest videos that I watched from him was about checking out an old generator. Since he lives in Canada and the power went out in the past. So just like MEF we get all variety of repairs. Just don't follow his advice by removing surface mount caps by twisting them real quick with needle nose pliers. I am sure it works but if you accidentally rip off the solder pads, that would suck.
    I've found the twisting technique works very well as long as the board is in good shape. Trouble is we want to remove those caps because they have leaked in which case the board is corroded and the traces will tear off.
    I have a double tip tweezer style soldering iron. I haven't tried it yet but it might be a good solution

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    Hey Mars,

    Haven't seen you in a while. Maybe I've just been missing you, but I'm always happy to see old timers post.

    Justin

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    "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
    "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

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    Stray Cap DrGonz78's Avatar
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    Yeah the board in the video is from a scope or something which has great quality board. For example, I would not try the twist off method on Casio midi guitar from the 80's. I think the soldering tweezers would work great! I use an old 10 watt pencil to get at those small surface mount caps. Sometimes I use a tiny bit of chip quik. But the boards I have worked on were really fragile.

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    I remove SMD electrolytics by shearing through the entire cap with some very sharp cutters. The leads should be in line with the jaws so they're not forced together under pressure. This method doesn't strain the pads, which by the time the cap needs replacing are often fragile. You're left with the plastic base moulding and the stubs of the legs. lift off the plastic and use whatever you like to remove the soldered connections.

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    Senior Member Mars Amp Repair's Avatar
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    Well, closed biz in 2012 and was doing other things.
    Moved from Denver to a suburb of Boise, ID and been working full time at a shop that still does audio and TV repair as well as appliances. Doing that until fully retire in 3yrs.
    So, started up Mars up out of my home. Interestingly, been doing things like 1940's radios, 1980's home organs, and believe it or not actually some guitar amps😁.
    Thanx for the good words....it feels great to be back in the loop...g

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    Lifetime Member Enzo's Avatar
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    The clientele is aging out, but here in Lansing I used to do a lot of juke box work. Especially rebuilding old Seeberg amplifier units.

    Organ owners are also aging out. We used to have a full time guy doing house calls on them. CHurches still have them. But growing market for the fancy electric pianos like Clavinova and the Rolands.

    Had a regular DJ customer, but he also has a snow plow on his truck and does that seasonally. Once he brought be the little joystick controller for the plow head. Seems one of the four directions wouldn't go. I opened it up and found a simple four microswitches. One was bad. I replaced it and charged the guy some nominal amount. He was happy as a clam, as the plow company wanted $300 for a new controller box, and they offered no parts or service on the boxes. He told all his plowing buddies.

    Just a couple ideas for expanding.

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    Education is what you're left with after you have forgotten what you have learned.

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    Supporting Member Drewline's Avatar
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    Interesting video series!
    Thanks Glen

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    Drewline

    When was the last time you did something for the first time?

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