Fisher 800c bottom cover?

Discussion in 'Fisher' started by mrwood200, Mar 10, 2017.

  1. mrwood200

    mrwood200 Active Member

    Messages:
    217
    Location:
    chicago, il, usa
    I have purchased a 800c receiver, only now to learn it does not have a bottom cover!
    While I discuss with the seller, I am curious on how much work this adds to my project...
    • Looks like heavy sheet metal, attaching to sides of the chassis.
    • The holes in the bottom secure the chassis to the cabinet?
    • I don't bend sheet metal, so I am going to have look for a parts unit or have it fabricated.
    Anyone else have to find a bottom cover? Is this a deal breaker or an easy fix?
    Any suggestions?
     
    Last edited: Mar 27, 2017
  2. MikeRam

    MikeRam Active Member

    Messages:
    150
    Location:
    Portland Oregon
    The holes on the bottom allow for ventilation. You can see the two holes on the lip on the side. Those are to secure the bottom along with the two clips you see on the left side of your picture. I happen to have the bottom off of my 800C right now so I can take more detailed pictures if you want. Let me know.

    Mike
     
  3. MikeRam

    MikeRam Active Member

    Messages:
    150
    Location:
    Portland Oregon
    VE0_8705.jpg
    I've circled where the chassis is secured to the bottom cover. The clip is threaded, and the holes on the side ridge are not. The thread is on the 800C chassis and the screw just goes through the hole on the bottom cover.

    VE0_8706.JPG
    A view of the whole bottom cover. There are lips on the sides and front.

    VE0_8708.JPG
    The four holes on the bottom are for the feet.
     
  4. rufleruf

    rufleruf AK Subscriber Subscriber

    Messages:
    763
    I've seen at least one on ebay over the last year. Maybe just be patient. The sheetmetal on these is pretty think. I suppose if you could drill the holes an HVAC sheet metal shop could fab it.

    PEM makes threaded sheetmetal inserts you could get for the feet - I want to say 8-32 pitch as a guess, but can verify for you if you want
     
  5. mrwood200

    mrwood200 Active Member

    Messages:
    217
    Location:
    chicago, il, usa
    All good info - thanks!
    Threaded tabs is not good news... harder$$ to reproduce.
    I am starting to lean towards waiting for a donor part.
    My new Fisher is a bit crusty, so I have some work to do before I need the bottom cover...
    [​IMG]
    I plan to use in cabinet, so I might rig up a temporary fix for the bottom. It appears that the chassis is secured to the cabinet via the bottom plate, correct? by using the chassis feet?
     
  6. rufleruf

    rufleruf AK Subscriber Subscriber

    Messages:
    763
    Usually the feet come off to secure it to a cabinet. Screws go through the cabinet bottom into the same screw holes the feet go in. I bet a bottom will turn up while you restore it functionally. Is that rust through the plating, or goo?
     
  7. bhamham

    bhamham AK Subscriber Subscriber

    Messages:
    2,032
    Location:
    TX
    You could make one out of masonite or plywood and use angle tabs to secure it to the chassis. A 500c bottom would probably work, maybe a 400
     
  8. larryderouin

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

    Messages:
    18,472
    Location:
    Glen Burnie Md.
    0905:400 won't work. not deep enough. A 500 might work, although with thelack of an AM section the depth may not be enough. I do remember reading at one time they were all different in depth.

    EDIT: 0910. I looked up the 500c and 800c specs. 11-7/8 vs 13"" Deep. 500c bottom won't work.
     
    bhamham likes this.
  9. bhamham

    bhamham AK Subscriber Subscriber

    Messages:
    2,032
    Location:
    TX
    Good info Larry!
     
  10. mrwood200

    mrwood200 Active Member

    Messages:
    217
    Location:
    chicago, il, usa
    Thanks for additional info. I had thought about another Fisher bottom, but will focus on finding an 800c.
    This is a thought for a temp fix. I got a thin sheet of plexiglas. I will need something on bottom to secure chassis to cabinet.

    Photo shows a combo of leakage & corrosion. Minor pitting elsewhere on chassis, no output tubes. But a good face plate, underneath appears clean & original.
     
  11. larryderouin

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

    Messages:
    18,472
    Location:
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    Looks like it sat in a damp basement forever. The paint on the transformers flaked off and the metal end bells leached causing the rust stain around the jumpers. The rust stain caused pitting and corrosion of the chassis. You can clean a good part of it up with a wire wheel and some CLR or other rust/metal converter. It's NOT going to be the bell of the ball but will be presentable.

    If you have a shop bend the sheetmetal, all you'd need to do is to drill the feet holes, ventilation holes and the side holes. If they have a computerized plasma cutter see if they can cut all the holes too. The tabs on the back aren't really needed. All they do is locate the back edge, and if you drill the side holes correctly, you don't need the tabs.
     
  12. mrwood200

    mrwood200 Active Member

    Messages:
    217
    Location:
    chicago, il, usa
    Thanks Larry - appreciate your input!
    Good to hear I can get away without have tabs. Should make fabrication easier. I will monitor the auction site & work on the electronics first. If I get to the end without finding a bottom, I will look for a job shop.

    Yes, the corrosion is a concern. I thought it was related more to the can cap than the transformer. The rest looks OK (see photos below). I have never had a piece with damage like this, so this type of rehab will me new to me. I will have to do something to stabilize condition & reduce future corrosion.

    [​IMG]
    upload_2017-3-11_12-5-38.png
    upload_2017-3-11_12-6-1.png
     
    Last edited: Mar 11, 2017
  13. MikeRam

    MikeRam Active Member

    Messages:
    150
    Location:
    Portland Oregon
    Has this receiver been fired up yet? Hopefully not. If there was moisture on the outside of the transformers, it's a good bet that there could be moisture on the inside of them also. If you fire it up, there is a possibility of the windings shorting out. I would definitely bake the receiver before you fire it up. Most people put it in the oven with the receiver upside down (components facing up like in your last picture) for a couple of hours. I.ve seen temperature recommendations somewhere between 125 - 175 degrees. I personally would keep it on the lower side since electrical components hate heat.

    The object is to evaporate any moisture inside the transformers.

    Mike
     
  14. fred soop

    fred soop Super Member

    Messages:
    1,640
    Might also help to take the bells off the transformers before baking.
     

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