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Fisher 500-B Restoration Process for The New Guy

Discussion in 'Fisher' started by Josey Wales, Nov 7, 2018 at 7:16 PM.

  1. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Hello, Everyone,

    I'm fairly new to the group and i've been using the valuable information on here for some minor projects in the past. Some great JBL 4311 posts about crossover updates etc. I want to say thanks for that. I have recently obtained a Fisher 500-B and I plan to restore it. My father had a Fisher set up in our living room for about 40 years so I'm certainly partial to the name. My father has since passed and In his honor I plan to get this amplifier back on the road to do something that I think he might have respected and in the process, learn as much as i can about this great amplifier. I'm ok with a soldering iron and I know the difference between caps, resistors and transformers but my knowledge on electrical stereo components is very limited. Schematics look like a foreign language to me. I want to do it right (without going for a degree in electrical engineering, too expensive, ha) so if I could get some advice or maybe some tips on the process it would be very helpful and I would be grateful. I'm sitting here looking at 4 tube amps I have purchased over the last 3 years thinking wow, is there anything better? Lol. After my research on here, I have noted some important steps to start with.

    1) Replace the selenium rectifier? (where would I find one and what does it look like? What are the specs on it?)
    2) Replace the caps? (Which ones? there are a lot of them)
    3) I think all of the tubes are original and they don't look burned up like the others i've seen so i would just keep those
    4) Are these kits on the auction site worth buying? A gentleman by the name of captain fantastic on there has a kit with an adjustable bias modification as well as the kit for replacing the insides of the cans on top.
    5) The condition of the amp is pretty good cosmetically and all parts appear to be intact (all original) aside from some missing knob caps but that will be the finishing touch after cleaning etc.
    6) I'd like this to look as original as possible
    7) I was thinking of starting with something that might be easy to get a "win" and some confidence and then branch out form there.
    8) Should i do this myself or pay someone to do it? I live in the Pittsburgh, PA area
    9) Thank you for this awesome forum and all of the great information contained within it. I didn't know so many people loved vintage audio equipment like I do. I just thought I was weird. No longer. Lol.
    10) Hopefully this thread made it's way into the Fisher forum as intended. Apologies ahead of time if it has not.
    11) Pics of the amp to come shortly (I'll try to get a shot of the undercarriage)
     

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    Last edited: Nov 7, 2018 at 7:33 PM

     

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  2. rufleruf

    rufleruf AK Subscriber Subscriber

    Messages:
    1,116
    Neat receiver! I just finished a 500-B for an AKer, so the parts list is fresh in my mind. To answer your questions:

    1) 8A 400V bridge rectifier - Mouser part number 583-BR84
    2) These need:
    2X .022uf 250V (orange drop or other)
    2x .047uf 250V (orange drop or other)
    4x .047uf 400V (orange drop or other)
    1x .01uf 600V (orange drop or other)
    1x .01uf 600V Safety (I use Mouser 80-R413I2100DQ00K)
    1x 10uf 50V axial electrolytic (original is 8uf 50V)
    1x 100uf 25V axial electrolytic
    2x 1000uf 50V electrolytic caps - these will replace one of the cans on the underside or you can restuff the cap or buy a replacement - lots of options on this, but it needs to be done
    Other cans may need attention - get it working then test.
    3) see if some one in your area has a tester. Mail them to me and I'll do it if you want, but this shouldn't be necessary.
    4) kits tend to have mark up - I can give all the mouser PNs I used if you want. you can easily build a bias adjust board. I'd be happy to walk you through what I did in the 500B
    5) you can do this - not hard if you take your time and do things one at a time.

    Get a CL80 (Mouser 527-CL80) inrush limiter too.
     
    tcdriver likes this.
  3. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    I really appreciate the quick response! I have a multimeter. Do I need something else for the testing? Or do you mean a Tube Tester? The PN's would be very helpful! Thank you very much, rufleruf! Also, I read somewhere on here that a "new step down resistor?" is needed after replacing one of the parts but i can't remember where that was. I'll have to try to go back and look. Thank you again!
     
  4. 1rebmem

    1rebmem AK Subscriber Subscriber

    Messages:
    20
    Location:
    Wilmington, NC
    I am currently restoring a 500B and am well into it.
    I think you have a good list to keep you busy for now.

    It might be best to test the receiver for proper operation after each restoration step/phase.
    My opinion is to replace the selenium rectifier and electrolytic caps first.

    You have options for the can caps:
    1) buy new cans ready to install like from Hayseed Hamfest
    2) cut the cans off on the topside flush with the can flange then remove the old guts from the can and replace with new individual cap's then reattach the original can's. Probably the hardest method but retains original look. I chose this method.
    3) Install new individual cap's underneath replacing the can cap's.

    I suppose it depends on your skill, preference and/or money to spend.
     
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  5. Rockyhill

    Rockyhill No marigolds in the promised land Subscriber

    Messages:
    3,166
    Location:
    Maine
    Last edited: Nov 8, 2018 at 6:52 PM
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  6. bhamham

    bhamham AK Subscriber Subscriber

    Messages:
    2,013
    Location:
    Austin
    Nice 500-B. Lots of experienced guys here to help. I know Rockyhill did an outstanding job on his and I think Rufleruf has done a few 500-B restorations.
     
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  7. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
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  8. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Awesome! Thanks!
     
  9. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Thanks guys! I just found the Fisher Sticky. Also a great source of information. The more i read, the more confidence I'm gaining. I think I can do this.
     
  10. 1rebmem

    1rebmem AK Subscriber Subscriber

    Messages:
    20
    Location:
    Wilmington, NC
    Josey..
    What is your game plan?
    I'm looking forward to your progress.
    Jef
     
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  11. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Thanks! I am doing a bit of research on here before I begin. I'm planning to gather the parts separately to save some cash rather than buy a restoration kit and hopefully learn a little more than i would if i just went with a kit. I'd like to start basic and replace the caps, rectifier and diodes, any resistors that i find to need replacing as well. possibly the power and volume switch then jump into building a board to individually bias the tubes although i have the original tubes so I'm not sure how necessary that is at this point. I know that If i don't do it now, with the restoration, I most likely won't do it later. I think i'll take the amp to a pro to have the realignment done on the tuner as I think that might be over my head. The goal is to keep it as original as possible. All of the knob caps fell off but i found them in the box, so i'll only need to replace one. i'm thinking this is going to probably take me months to complete as I work and have other obligations in between so when i get "my" time, I'll work through it. i'll begin to post photos of the progress soon. I'm currently restoring some JBL 4311 wx-a's that I plan to pair with it. It does seem a little overwhelming but as I read, I gain more confidence. I want to get to know the amp before I do anything.
     

     

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  12. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    I just saw this, sorry. I think I'll go with what you said and do the rectifier and electrolytic caps first. Thanks for the information! I may just go with the can caps for ease of installation because i'm so new to this.
     
    Last edited: Nov 10, 2018 at 6:34 PM
  13. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Also, I've read that you can test tubes with a multimeter. Is this possible? I really don't have access to a tube tester.
     
  14. 1rebmem

    1rebmem AK Subscriber Subscriber

    Messages:
    20
    Location:
    Wilmington, NC
    I like your approach!
    One step at a time learning the amp as you go. That will help if you need to troubleshoot some issue.
    Doing the cap's, rectifiers and check resistors. After that it would be good to verify all the B+ voltages look normal.
    Then on to the next phase.
    Best of luck,
    Jef
     
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  15. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Thanks you! i will definitely do that.
     
  16. Tim D

    Tim D AK Subscriber Subscriber

    Messages:
    1,337
    Location:
    Melbourne, FL
    Well, you could test the heaters to make sure they aren't open or shorted to the other pins. I don't know what else you might check with a multimeter. Having said that I think to do a proper check of the tubes it helps to have a good amp to test them out in. It also helps to have a Tube Tester available for basics tests like shorts, gas, general health, and if possible conductance. If you need help testing your tubes maybe a local AK'er can help you out. I picked up a vintage Knight KG-600 emission Tube Tester and replaced the resistors and cap and re-calibrated it. That was a fun project.
     
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  17. thornev

    thornev Well-Known Member

    Messages:
    515
    Location:
    Mid Hudson Valley, NY
    Josey - If you send me the tubes I'll test them on my B&K 707 tube tester. I'm in eastern New York. PM me if interested. Thorne
     
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  18. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Thanks, Thornev! I may have found a gentleman locally whom is selling a few tube testers as a lot. I asked him if he may be willing to sell me one of them out of the lot, if he doesn't, i will take you up on that. Thanks so much for the offer!
     
    Last edited: Nov 12, 2018 at 12:37 AM
  19. Josey Wales

    Josey Wales New Member

    Messages:
    30
    Location:
    Pittsburgh
    Thanks for the information, Tim! That sounds pretty awesome. I hadn't thought of restoring a vintage tube tester but now you have me thinking. Ha!
     
  20. Tim D

    Tim D AK Subscriber Subscriber

    Messages:
    1,337
    Location:
    Melbourne, FL
    Yeah, I picked up my Knight from the Goodwill site for a good price. It was originally a kit. It came with the assembly manual and a couple of books including some addendum tube tester settings. In going through it I found that almost all of the carbon composite resistors were way off spec. It's now fully restored and I can use it on my projects. It is a late enough model that I haven't bumped into anything I can't do gas, short and basic health tests with it. The ultimate test though is when you plug those tubes into your unit and they work great! BTW, the refurb of the tester was much easier than the refurb of my tube stereos.

    Just be aware that there are parts for these tube testers that might be difficult to obtain such as meter movements, selector switches, etc. I was lucky with mine that all those parts were just fine.
     
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