help getting an X-100 working

Discussion in 'Fisher' started by craig tilley, Sep 13, 2017.

  1. craig tilley

    craig tilley New Member

    Messages:
    2
    Hi All. This is my first post so let me say thanks and hope some of you knowledgeable people can help me figure this thing out.

    So, I got an X-100 from a yard sale for 20 bucks. Of course it didn't work but taking it to a shop told me it needed a new power transformer. Well, I've finally procured a new replacement and I'm capable of installing it but I have a couple questions. All the wires coming out are unique and match the old transformers wires save the fact that there are two matching red and two matching black wires. Am I correct in assuming that these can go to either spot already occupied by the same color wire?

    Okay, question 2: Do I need to replace any caps? It all looks good in there but obviously I don't want to damage anything further. I read one place I can damage the transformers and I can't have that! :) If that's the case where can I get replacements?

    Well guys and gals, any help sure would be appreciated. Thanks again!
     
  2. Omegaman

    Omegaman Ultra Super Member Subscriber

    Messages:
    2,846
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    Scottsdale, Arizona
    Regarding the caps, there is a reason that the PT failed

    If you want to be secure in the knowledge that you have done everything to make the unit work and last then yes, recap the bastid
     
  3. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    8,947
    Location:
    Ball Ground, GA
    Hi Craig -- Welcome to the AK Fisher Forum! Regarding your questions:

    1. Yes, the same color wires can interchange with each other.

    2. The caps you should strongly consider replacing are the power supply caps located in the round metal cans. You can get very workable close replacements from Antique Electronic Supply, or exact replacements custom made from Hayseed Hamfest. You should also consider replacing at least the four mylar caps that coupling the signal to the output tubes. A pic would help a lot here, as some types of caps used in this location rarely if ever fail -- others tend to fail more frequently. A pic is always most helpful in this regard. If they need to be replaced, AES is again your source.

    There's plenty of great folks here who can help you replace these components and help you safely restart the unit as well if you need the help.

    Congrats on getting a Fisher, and good luck with it!

    Dave
     
  4. larryderouin

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

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    Get new rubber bands and wind them REALLY TIGHT! :biggrin::biggrin:

    Seriously tho. I'd double check the shop tho (I tend not to trust them). Get or borrow a variac, AND A Dim Bulb Tester(DBT), and disconnect ALL of the secondary windings one pair at a time. connect a meter set for AC volts to 2 leads and with the cord connected to the variac and DBT bring the voltage up to about 60V. test each pair. Voltages should correspond to approx 50% of the normal voltage for each pair. If not then the transformer is definately bad. Replace the transformer.

    What Dave said about the caps. Might as well do the resistors between each 2 sections on the caps too. Selenium Rectifiers (if applicable) get replaced.
     
    Last edited: Sep 13, 2017
  5. craig tilley

    craig tilley New Member

    Messages:
    2
    Thanks for the feedback! I've already Okay, I think I can figure these cans on top out. Then how about that on big minimite dry electrolytic cap. I had a hard time finding that exact value. Is there some wiggle room there or should I just look harder... or leave it? Here are a couple pictures. Let me know if you see anything. And then when I get it all replaced I can borrow a variac from a friend and just bring it up slow? I've had a slew of tube guitar amps but never a hifi. Can't wait to hear this thing!



     
  6. gadget73

    gadget73 junk junkie Subscriber

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    33,593
    Location:
    Southern NJ
    pics don't show up.

    What value are you looking for ? Most of this stuff has wiggle room on value. Voltage can go up, if you keep the value within 20% of the original it will be fine.
     
  7. larryderouin

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

    Messages:
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    Location:
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    Capacitor Value's changed slightly in the Early 70's. Most all caps up to that time had tolerances of up to +90% and -50%. Today most standard caps have tolerances of 20% +/-. If that Dry Lytic is (C-16) 20uf 350V use a 22uf 350V. If it's (C32 or C33) 25uf 6V use a 27uf 16v or 25v.
    The Can caps (C15A thru C) 100uf 150V, 40 350V, 40uf 350v can be replaced with a 100uf,47uf,47uf @ 350V. (C27A&B) 40uf,60uf @450V replace with 47uf and 68uf @ 450V. Hayseed HAmfest would probably be the best place to get replacement CAN's. Or you can find pencil type caps to restuff the old can's. Nichicon UCS series would work.

    Larry
     

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