How to quickly repair Fender Bassman guitar amp negative bias failure

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  • čas přidán 10. 09. 2024

Komentáře • 53

  • @whatsstefon
    @whatsstefon Před 3 lety +2

    Nice little repair. One of the Bassman 50s I did on my channel recently came back, and while the customer was here I quickly discovered major hum, and opened the dog box to immediately see the terminal completely broken off one of the main filter caps in series. Replaced it, tested the amp, which was so dead silent I didn’t think it was on. We plugged a guitar in and had fun with it.

  • @3butalcomp3
    @3butalcomp3 Před 3 lety +1

    Hey Terry, I like your videos, & it's always nice to see a wine bottle on the bench. You're a funny guy, a glass of wine in hand & excellent vintage gear in the shop. You know your stuff though & I give credit where credit is due. It's just how some of us are "wired" I'd have to say. I've been a tech. since 1976, @13 yrs. old & excelled quickly in this field. Like so many of us, it all started out with CB for me & I loved it. Total satisfaction in the Electronics field. -Yeah- the thrill of it all! There are many people here posting videos ranging somewhere between guessing, yet unfortunately smoking up priceless cool stuff but -really wanting to learn though ...and the laid back Tech who knows the deal. No offense meant to some of these guys, at all. I just enjoy the vid's where things fall into place sort of like a bottle of good wine on the BENCH, a clean bench setup, and of course -communication gear & Amps all within view as you move on to the next job. And BTW: "Fender Bassman" ? **You know Jack Cassaday IS the Bassman** right? Keep up the good work!

  • @GregoryHillSr
    @GregoryHillSr Před 3 lety +2

    Quick indeed!! I see the website - nice touch with your helper! Didn't know your a BC guy... used to train there so I know I'm in good hands.

  • @russellhetherington7085
    @russellhetherington7085 Před 3 lety +2

    I just bought one of these Terry. As always, your videos are informative and on point. Thanks mate 👌👌

  • @michaelmcnicholl608
    @michaelmcnicholl608 Před 3 lety +2

    Great video Terry. Sorry to hear about your wife's mother. I'm a little late on that, but I just heard today. Thanks again for the help today also, I really appreciate it.

    • @Tonetwisters
      @Tonetwisters Před 3 lety +1

      Dittos on that. God bless to you and family.

  • @cheycasters
    @cheycasters Před 3 lety +2

    Dang I love these vids and I just play Geeter for 50+ years

  • @bobbarcus8310
    @bobbarcus8310 Před 3 lety +2

    Fender built some tuff stuff thanks

    • @Tonetwisters
      @Tonetwisters Před 3 lety +1

      As a 59-year user, with 35 on weekend stages, I can attest to that!

  • @mikebracey8832
    @mikebracey8832 Před 3 lety +1

    Hi Terry, Please give us radio guys a little love.

  • @edwardhannigan6324
    @edwardhannigan6324 Před 3 lety +1

    Nice fix Terry.. Thanks for sharing and the expert info..Ed..UK..😀

  • @rciancia
    @rciancia Před 3 lety +1

    Good easy fix my friend. Makes you wonder how they blew that diode.... or was it just weak... you never know... Great fix

    • @d-labelectronics
      @d-labelectronics  Před 3 lety +1

      Hi Ron, Thanks for the $$, very cool of you Sir. I will be making a follow up video of this amp maybe discover other issues. Had to see what the customer wanted first.

  • @garysmith1532
    @garysmith1532 Před 3 lety

    Terry, I'm desperate to know more about my Fender DR2 amp circuitry, I'm a retired electronics tech, but solid state, the DR2 input system is doing my head in, if you ever get one of these I'll gladly make a contribution, love the channel, Gary , England

  • @bkbinj6320
    @bkbinj6320 Před 3 lety +1

    Another save by D-lab.

  • @bluesbondsman
    @bluesbondsman Před 3 lety +2

    28 ma is awfully cold bias for those 6L6GC's ! closer to 38 ma would sound so much better !!

  • @russellhltn1396
    @russellhltn1396 Před 3 lety +3

    But why did the diode fail? This doesn't give me a warm fuzzy. Did the old diode have a low PIV that got taken out in an electrical spike? Looking at the schematic, I don't think a shorted output tube could do that.

    • @d-labelectronics
      @d-labelectronics  Před 3 lety

      Have no idea man

    • @emilianoranfagni7198
      @emilianoranfagni7198 Před 3 lety +1

      Overheating ( Thermal runaway) ? The failure of another component ( simply to check, if the ampli not work again)? Overcurrent ? Overvoltage ? Simply aged or stressed ? Diodes can fail open, closed, and in between ( fail closed and open failure is a subsequent event) .Who knows.

  • @dhpbear2
    @dhpbear2 Před 3 lety +2

    10:18 - I'm still curious what caused that pop!

  • @pjf7943
    @pjf7943 Před 3 lety +3

    Why did you not check for matching, then measure and set the plate/watt dissipation for the highest current draw pt, which would, I defend, be the more correct way to set the pt bias for a properly matched (or unmatched) set of pt's, instead of "good enough for me"..??? Based on what.?? The other problem I see is "a really cheap repair".. Yes, the parts are cheap, but discovering the problem and setting a course of action is not.. Would you divulge what you ultimately charged for the repair..???

    • @d-labelectronics
      @d-labelectronics  Před 3 lety +2

      There will be a part 2 with more info, This was just initial inspection and revive

    • @pjf7943
      @pjf7943 Před 3 lety +2

      @@d-labelectronics As a suggestion, you might include the "part two" and possible outline of the next procedures, as many boob toobers will think the service is completed, no matter if the client wants more work done or not..

  • @geemac7267
    @geemac7267 Před 3 lety +2

    Hey Terry, I don't know if it would interest you to do so, but you could get a cheap looper pedal to test your amps rather than the signal generator. Not that there's anything wrong with the signal generator of course, but you could have a friend play some chords and lead lines into the looper pedal and then get actual guitar sounds through the guitar amps.

  • @jdmccorful
    @jdmccorful Před 3 lety +1

    Looking good!Enjoyed.

  • @dwightjt
    @dwightjt Před 3 lety +1

    How can a screen
    Grid be shorted and burn the screen resistor? screen grid is
    Far away from the plate or cathode and heater but it is next to G1 control grid. Far from G3 suppressor grid in a pentode.beam
    Power tetrodes
    Don't have a G3 but beam confining plates
    Connected to the cathode. I know the heater can get shorted to the cathode the heater inside the cathode is insulated
    With aluminum oxide
    That can fail. The cathode is coated with
    Strontium oxide barium oxide or both so how can Grid 2 screen grid get shorted to anyting and show up on a tester or a burnt screen resistor? What does it short out to?
    This may sound like a funny question. I just don't see how.

  • @srtamplification
    @srtamplification Před 3 lety +1

    Great website Terry. I used to have a website with GoDaddy myself. I liked how you could customize it the way you want it. You should put a link you your CZcams page on there as well.

  • @wolfgangkrauss7270
    @wolfgangkrauss7270 Před 8 měsíci

    Hi i have a 66 bassman. There are 7 Diodes in the biasboard. Will they be ok after 60 years or is it better to change them all to 1n4007 diodes. If they are to change can 1 insert only one 1 n4007 instead of the three or better install also 3 new Diodes.because one new is rated with 1000v. Thank you and Greetings from Germany

  • @ko2fjb
    @ko2fjb Před 3 lety +1

    I enjoy watching your videos. I took your advice a purchased a leader LAG 25 and I'm curious if you have an owner or service manual for yours. I'm not sure what the output voltage is supposed to be since it drops to zero when I turn it to the x1 on the output multiplier. This unit is like brand new and don't want to get into it until I know for sure what the specs are supposed to be.

  • @ross3818
    @ross3818 Před 3 lety

    There's that honking big screw by the orange Spragues. Is that normal?

  • @benjaminmoore37
    @benjaminmoore37 Před 3 lety

    Hi Terry, I'm so sorry to hear about your Mother in Law. Great videos! I've been watching for a few years now but have just subscribed. Thanks again for the Variac. I've noticed that you are now again using a manual range meter but tried an auto range meter for a while and before you were not a big fan of auto range meters. What are your thoughts now?

  • @Dasrocknrolla
    @Dasrocknrolla Před 3 lety +1

    link in the description?

  • @tomk1tl39
    @tomk1tl39 Před 3 lety +1

    I noticed you have 'shop hours' . . .did you retire ? ? ? If so, you have a great future in HR/Amp repair.

    • @d-labelectronics
      @d-labelectronics  Před 3 lety

      Not Yet, Hope to soon. Yes, I need to edit the hours

    • @tomk1tl39
      @tomk1tl39 Před 3 lety

      @@d-labelectronics I guarantee you, when you do and do amp/HR repair work, you will definitely have to hire a good 'assistant' (preferably a knowledgeable young one) to help you with the work...you do 'outstanding work' along with UD !

  • @Tonetwisters
    @Tonetwisters Před 3 lety +1

    Just sent you a miserly donation via PAYPAL. Yay! At least it's something, finally!

    • @d-labelectronics
      @d-labelectronics  Před 3 lety

      Very nice of you. Thank you for thinking of me. Plan to review the donations on my next vid.

  • @cheycasters
    @cheycasters Před 3 lety +1

    going there now Mr. T

  • @pauldavis6356
    @pauldavis6356 Před 3 lety +1

    That's a nice looking amp stand. Is it home-made?

  • @caseykittel
    @caseykittel Před 10 měsíci

    10:10 cheers!

  • @DAVIDGREGORYKERR
    @DAVIDGREGORYKERR Před 2 lety

    Did the female Amplifier Tech slip up?

  • @Tonetwisters
    @Tonetwisters Před 3 lety +1

    DOA. Bassman needs one of them heart paddle things ... BTW: If you go on the Internet and get NOW brand Sunflower Lecithin in 1200 mg, and take 6-10 / day, they will clean out your (everybody's) arteries, so YOU don't need that heart paddle thing. lynncapehartwellness.com blog 6
    I wondered how often those SS rectifiers failed. When rectifiers go, amp no go.

  • @daleburrell6273
    @daleburrell6273 Před 3 lety +1

    ...the amplifier HUMS because it doesn't know the WORDS-(?)

  • @ronfrey5327
    @ronfrey5327 Před 2 lety

    Are you open ?

  • @petereff5724
    @petereff5724 Před 3 lety +1

    Interesting videos but these amplifier repairs are all starting to look the same. There must be other stuff to work on.

    • @d-labelectronics
      @d-labelectronics  Před 3 lety

      Yes Sir, good input, was just talking to my son about the same thing. Plan for new content soon

  • @aaspookyaa
    @aaspookyaa Před 3 lety +2

    Nice George Bush imitation! Not gonna do it.!