Quick and Easy 400 Phase Inverter Adjust.

Discussion in 'Fisher Forum Stickies' started by larryderouin, Dec 1, 2013.

  1. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Alan; Don't confuse the transformer/speaker grounding with the phase inverter. WITH POWER OFF(pull the plug and bag it) Ground capacitor C-27A, then do the adjustments. Pin 3 is static, and pin 1 is adjustable. AGAIN NO POWER!
     
  2. RUmad

    RUmad Well-Known Member

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    Larry, I LOVE your enthusiasm! LMAO! Thanks for the info. I'm most obliged. To be clear, the power will most definitely be off. Thank you sir!

    Alan
     
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  3. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    I just hate seeing guys trying to become part of a A.E.D. (Automatic External Defibbrillator) either intentionally or by accident. It's not really enthusiasm, more emphasis if you will. 40 years in Emergency and preventive medicine will do that to you.
     
  4. RUmad

    RUmad Well-Known Member

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    I understand and completely agree. I got zapped, when I first started tinkering, with about 1400 volts. Luckily it was very low current and I only had one hand in the chassis. It was a Bell & Howell scope transformer I used for my first preamp build. Let's say I've been extremely cautious since then. :yikes:
     
  5. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    OUCH!!! That'll definately put a kink in yer hair!!
     
  6. RUmad

    RUmad Well-Known Member

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    743
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    Yes sir, I was totally reevaluating my idea to work with tubes. Lol. Glad I stuck it out though!
     
  7. RUmad

    RUmad Well-Known Member

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    HOLY $H!T was that easy!! Thank you again Larry! I'm eternally grateful that we've not only got real experts on here, but experts willing, even eager, to help us little people. Not only would I NEVER have touched those PI pots, for fear of throwing everything out of whack, but they already were way out of adjustment. Now both sides are perfect. Y'all rock.

    Alan
     
  8. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    I got nailed by a TV Flyback transformer when I was 7. It had been sitting on Dad's bench for a couple of hours and I grabbed it wrong (never grab one by the H.V. terminal end and ALWAYS wear thick rubber gloves!!!) Literally knocked me on my a__ across the room. Wasn't fun, but Dad laughed about it after all was said and done (and I had been checked out by the ER doc's.) Wasn't the 1st time getting zapped, but the last for a Flyback transformer.

    Don't thank me, (SHORT VERSION) I was just the instigator with the original question to Dave. He answered back, with his usual 6 page dissertation on phase inverters, dumbed down for 3 celled moron's like me. So then it snowballed into the thread it is. I did the rest of the research on the receivers and Dave vetted it. He's got more than enough on his plate without having to run down minor stuff like adjusting P.I.'s without an analyzer. Plus I learned a few things along the way. Now I've got to look into the amps and how they are done. Luckily part or most of the answer is in Dave's previous posts.

    The more and better that we all help each other the stronger the mind pool becomes. No piece of information here is useless. Even the most esoteric piece of dope from 1946 can be just the thing that get's another FISHER back on the road and running.
     
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  9. RUmad

    RUmad Well-Known Member

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    743
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    I agree, and I do thank Dave, for this particular thread, and helping me with other issues on my first Fisher rebuild. I thanked you specifically for walking me through this process. I can't say it enough, I love it here at AK. It's one thing to build something and have the satisfaction of it working, it's taking it to the next level to be able to say, it works, AND I know it's done CORRECTLY. So if I were to list everyone in order to thank them, I'd more than likely accidentally forget some names, so thank you everyone. I've got a few very minor details to work out, but within the week id say I'll have this in my system, and I can't wait. Albeit missing ONE dang knob on the tuner. It might've worked without help, but it never would've been 'right'.
    And after this? Two more boxes of Fisher gear to rebuild! Yes!!
     
  10. Kelshar

    Kelshar New Member

    Messages:
    49
    Location:
    Mesquite, TX
    can someone help me located the C525C in this photo? I found it on the schematic but am unable to physically. sorry if someone has already pointed this out but I'm unable to locate it on a search.
    I recently purchased this 400 at the end of May. My first venture in tubes. everything seems to work but I just want to restore it to its full potential, make it last and be protected.
    thanks!
     

    Attached Files:

  11. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    8,773
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    With 400 receivers, you need to specify whether you have an early or late model version (serial #48000 is the break point), as there are significant differences between the two units. From your pic, yours is a late model version.

    May I assume that you are really referring to C52C -- and not C525C? There is no such capacitor listing in any 400 receiver. If it is C52C you are referring to, it is located in the four section capacitor can closest to the RF tuner box, of the two rear capacitor cans.

    Since this thread is a sticky pertaining specifically to the phase inverter adjustment process, it would be best for you to ask these types of questions in the general Fisher forum, so that this thread can stay on its dedicated topic.

    Good luck with your restore!

    Dave
     
  12. Kelshar

    Kelshar New Member

    Messages:
    49
    Location:
    Mesquite, TX
    ooops, sorry. Yes, it's the late model version, serial number# 63067 and a typo on the *C52C*. I'll start another one in the general forum. thanks!
     
  13. vintelectra

    vintelectra AK Subscriber Subscriber

    Messages:
    356


    Hi PI fans: great thread! I use the THD method, but what about just equalizing signal voltage on both pwr grids?
    I got the "defibrillator risk". Martin
     

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