Fisher MPX Adapters

Discussion in 'Fisher Forum Stickies' started by TheRed1, Dec 22, 2011.

  1. vendo81

    vendo81 AK Subscriber Subscriber

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    Hello Dave. No, there is not a stereo indicator light installed but he did ask if I wanted one. I decided the only way would be to drill a small hole which I didn't want to do.
     

     

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  2. vendo81

    vendo81 AK Subscriber Subscriber

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    I recently bought several Fisher items up in the LA area and included was a 202-T with a MPX-50. The MPX-50 was a factory plug-in replacement for the FM-100, 100-T, 202-T and for the same models in a radio/phonograph combination with the Coronet model 808, Coronet II models C55 and C55A, Statesman 1010 and Statesman II model ST-70.
    I will see how this factory plug-in performs once the 202-T is rebuilt. Here's the first page of the MPX-50 manual.

    MPX-50.jpg
     
    Last edited: Apr 9, 2016
  3. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Vendo -- Hopefully you got a schematic, or at least can post an underside pic so we can see how different it is from the more traditional Fisher MPX sub-chassis. It may not be that different at all -- just in how the terminations/connections are made.

    What is interesting however, is that Fisher in fact tried to retrofit a proper MPX unit for those receivers and tuners that were REALLY designed for the MPX-20. It brings up the age old questions again of how did they indicate stereo reception? How did they cause the tuning indicator to indicate optimum stereo channel tuning? Or, did they not address these things at all? Any info you can glean will be appreciated!

    Dave
     
  4. vendo81

    vendo81 AK Subscriber Subscriber

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    Here's photos of the MPX-50. It uses two 12AT7's and one 12AX7. One thing I noticed different than the ones I've seen is the large 20UF 250V cap on top. I'll scan the 4 page manual. No schematic but lots of information.

    MPX50 2.jpg MPX50 3.jpg
     
  5. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Looking forward to the scan! From what I can see of it, this unit is an early version of Fisher's time division concept, but lacks the refinement of their later WX and MPX-65 (and other) units. It uses two single diodes for detection of the regenerated sub-carrier, as opposed to the dual ring detectors of their later units, but still functionally operates the same. Should be very interesting to get your impression of how well it performs!

    Dave
     
    Last edited: Sep 10, 2016
  6. Scifi

    Scifi Super Member

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  7. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    For those of you who have a 59' or 60' Series 610 Consolette you can adapt it for Multiplex. The '60 Custom Electra is basically a 610 and a 560 companion in one cabinet and uses the same amp's and tuner. The C.E. tuner has been wired for MPX. Using the 60' Custom Electra Schematic, you can adapt your Consolette to accept MULTIPLEX. I did this a couple years ago and it works very well. I'm using a Sherwood a3mx converter as it's small enough to be shoehorned into the cabinet but a mpx-200 is a viable alternative. The MPX-100 will be a sit on the floor underneath deal or mounted to the back of the 610. I detailed it in this thread. http://audiokarma.org/forums/index.php?threads/610-consolette-chassis-overhaul.547187/
     
  8. Scifi

    Scifi Super Member

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  9. RUmad

    RUmad AK Subscriber Subscriber

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    Begging your pardon guys, Larry have you gotten around to fixing that transformer issue on your 100?
     
  10. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    Yeah. I had a new one made by Heyboer that summer. I used the specs from the SAMS photofact for the MPX-100, sent them my old one and asked them to incorporate the endbells from my original. Works like a charm. IIRC the cost was something like $78.00 shipped.
     
  11. RUmad

    RUmad AK Subscriber Subscriber

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    Ah, ok brother. Never mind then.
     

     

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  12. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    From POST #1
    Red's quote refers ONLY to the 1st series (serials10001-19999)
    The 2nd (20001-39999 serials) and 3rd series (40001-49999 serials) used the following CHANGED tube lineup. 1-12ax7, 1-6AB4, 1-6BL8 (ech80), 2-12AT7's

    I've checked with numerous sources, and so far it appears that FISHER never did publish alignment instructions for any of the MPX-100 or MPX-200 Multiplexers.
     
    Last edited: Apr 26, 2018
  13. Drugolf

    Drugolf AK Subscriber Subscriber

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    Great thread and very informative.

    I have a TA600 currently being restored. The manual suggest the MPX-10 as an example of the MPX unit to add so do I assume the TA600 is set up for the early Crosby system? If so, where so I start if I want to add an MPX unit? Which one do I look for?
     
  14. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    The Crosby system was made defunct by the FCC Ruling in 1961, with the Zenith/GE system being the standard MPX. You can use any available mpx unit with the TA-600, as long as it's designed for the ZENITH/GE System. The MPX 10 & MPX 20 units are now relegated to nice to look at pieces that belong in museums or collections. They aren't a viable unit for use. Look for either a MPX 100 later unit (see post 52) or a mpx 200 if you want to keep it FISHER. I have a Sherwood M3ax and it works just fine with all of my tuners and receivers to get mpx. Actually it's in better tune than my MPX 100.
     

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