Fisher 400 rectifier. Is this original?

Discussion in 'Fisher' started by daveyh, Jul 15, 2017.

  1. daveyh

    daveyh AK Subscriber Subscriber

    Messages:
    1,341
    Location:
    USA
    This looks like it is original but the guy who sold it says it has been changed. Most of these I have seen are metal cased. This is plastic. But it looks like the circuit has not been touched. This serial number starts with 699xx X.

    Has anyone seen these before?
     

    Attached Files:

  2. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    8,985
    Location:
    Ball Ground, GA
    Yep. It's original. The later series 400s in fact had silicon bridge rectifiers installed in place of the prior version's traditional selenium at the time. You really don't need to replace it unless you need the peace of mind. Don't know of any of the original silicon bridges that have ever failed though........

    Dave
     
  3. daveyh

    daveyh AK Subscriber Subscriber

    Messages:
    1,341
    Location:
    USA
    Thanks Dave! Good to know I don't have to replace it.
     
  4. Dave451

    Dave451 AK Subscriber Subscriber

    Messages:
    780
    Location:
    Philly area
    My late model 400 had a silicon bridge like this. Did not replace.
     
  5. arts

    arts Super Member

    Messages:
    2,537
    Location:
    Qc, Canada
    Didn't some of those rectifiers come with glued-on heatsinks?
     
  6. larryderouin

    larryderouin You can be sure if it's Westinghouse??????? Subscriber

    Messages:
    20,127
    Location:
    Glen Burnie Md.
    Not that I'm aware of. I've seen them on the side of the chassis on a T-strip, and on the T-Strip mounted to the RF Box, why I haven't the foggiest! You'd think you'd want to keep a minimum amount of distance between the AC and RF sections, even shielded. But no heatsinks. I use the table style bridge and mount them right on the side of the chassis with some heatsink grease between the bridge and the chassis.
     
  7. Patrice B

    Patrice B AK Subscriber Subscriber

    Messages:
    2,037
    Location:
    Montréal, Canada
    Arts, check your PM, my Sherwood is sick...

    Sorry being OT...
     
  8. HH-Bham

    HH-Bham AK Subscriber Subscriber

    Messages:
    397
    Location:
    Birmingham, AL
    I think I do. I'm going to start a new thread here in just a few minutes.
     
  9. gadget73

    gadget73 junk junkie Subscriber

    Messages:
    33,468
    Location:
    Southern NJ
    not to say they can't fail but generally when silicon diodes die, its because something else killed them. They rarely fail just because the day ended in Y.
     
  10. Dadbar

    Dadbar Super Member

    Messages:
    1,812
    Location:
    Waltham & Gloucester MA
    Mine did.
     
  11. Destructor

    Destructor Super Member

    Messages:
    1,457
    Location:
    Braintree, Mass
    One of mine also came with an attached heat sink. Don't know when they switched but both of mine have the one additional IF can but one had selenium, I'm assuming selenium because someone had already replaced the bridge, the other came with the silicone.
     

Share This Page