FM-200-B Acquisition

Discussion in 'Fisher' started by audmod01, Sep 16, 2017.

  1. audmod01

    audmod01 AK Subscriber Subscriber

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    It is a disease! I just bought a Fisher FM-200-B that was mislabeled as being a FM-100-B. The front panel clearly says it is a FM-200-B and the IF stage count is correct. After restoring the 202-R I don't feel it will be any more of a challenge. I will work on some pictures for next post.
    Joe
     
  2. audmod01

    audmod01 AK Subscriber Subscriber

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    901
    Location:
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    OK, here are a few pictures.
    200-B web 01.jpg 200-B web 02.jpg 200-B web 04.jpg
    The cabinet is sort of mangled, but may be serviceable with replacement of the front trim. I might be able to use some walnut wood and an router to make equivalent pieces to replace the broken wood there. The rest of the cabinet looks OK. This one is definitely a FM-200-B with the microtune circuit and the muting plus the nuvistors in the front end. The picture showing the unit tuned to a station shows the signal level meter up around 5 on the scale, so it is unlikely to have the silver mica disease. This one may be a keeper. It can stand a good cleaning and will make a really nice unit.
    Joe
     
  3. AlTinkster92

    AlTinkster92 AK Subscriber Subscriber

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    Congrats on the 2nd best Tuner Fisher ever made Aud! I have one that Dave G went thru and its all the tuner one could ever need. How does your Micro tune work? Definitely a keeper! Al
     

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  4. notdigital

    notdigital AK Subscriber Subscriber

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    If you're looking to patch in a piece to replace the broken part on the right side, I have a scrap piece from a cabinet i built a while back. It went into the reject pile b/c the piece slipped while I was cutting on the table saw. The angled part is fine tho if you think you can splice a piece in. If you're interested I'll send it along.
     
  5. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Nice grab Joe! Definitely a 200B as you say, although the IF stage count is identical between a 100B and 200B.

    Good luck with it!

    Dave
     
  6. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    901
    Location:
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    On my 202-R the Microtune did not work when I received it. The spring loaded contact that touches the shaft of the FM tuning knob was bent away from the shaft. I reformed the spring leaf so that it touched the shaft again and it began to work. As you touch the knob the circuit turns off the AFC of the set and then when you release the knob it tunes to exact center of channel. At one point in working on IF alignment I got it wrong due to technique being used, but I corrected my technique on alignment and got the tuning correct and the Microtune circuit resumed working correctly. One of the most important parts of the alignment for the Microtune to work correctly is proper adjustment of the Ratio Detector secondary. That has a big effect on the AFC voltage.

    On a FM-200-B the Microtune circuit works in the same way, so the circuitry is practically identical. Dave pointed out that aligning the IFs of these sets requires that the input signal be reduced in level as you proceed from IF stage 1 to 2 etc. The idea is to keep from having a following stage from going into limiting so that you can find the real peak at 10.7mHz.
    Joe
     
  7. audmod01

    audmod01 AK Subscriber Subscriber

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    After I get the 200-B checked and repaired if necessary, then I will have to get an X-202-B won't I:D
     
  8. audmod01

    audmod01 AK Subscriber Subscriber

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    I should add that I will not have the unit in hand until Sept. 25th. It has not been shipped yet.
    Joe
     
  9. larryderouin

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

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    Yeah. Knowing your luck, one will bounce your way fairly quick.:music:
     
  10. notdigital

    notdigital AK Subscriber Subscriber

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    Here's a quick shot of the piece. I'll send it along:

    DSCN0095.JPG
     
  11. audmod01

    audmod01 AK Subscriber Subscriber

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    Location:
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    Notdigital;
    Thank you very much! I appreciate the help. Once I get the actual unit I can get a better idea of just how to deal with the damaged part. There is some minor damage on the other side too, so I can look at how to deal with that side too. I am gradually getting better at dealing with cabinet issues. I have a lot to learn there. Unfortunately most of my friends locally do not know how to deal with restoration of cabinets so much as how to make a cabinet from the beginning. I have learned some by looking at threads on the antiqueradios.com website on the forum for cabinet restoration.

    Larry;
    I keep watching for a suitable X-202-B, but most are either rust buckets or have already been restored and going for $1-2K or so - a little too rich for my budget. I have grown tired of dealing with chassis that have excessive rust and corrosion. It takes a lot of work to bring them back to anywhere near the level I prefer. I often have spent more than a month of work cleaning and polishing. I expect to pay more for an X-202-B just due to average prices these days.

    Joe
     
  12. Patrice B

    Patrice B AK Subscriber Subscriber

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    Congrats, in working order it's a great tuner but there's a lot of circuitry in there: relays, nuvistors, etc...
     
  13. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    901
    Location:
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    Patrice;
    I am not worried about RCA nuvistors, as I was working in service at a dealer when these were introduced. I also worked for RCA Service Co. for years servicing their consumer products (color TV, stereos, VCRs etc.). The relays are a known fault point in any tuner using them. Periodic burnishing of the contacts with something as simple as a thin card or paper will usually do the trick. I had to do this on my 202-R tuner recently. It is an even older tuner with the microtune circuit and 6 IF stages instead of the 200-B which has 5 IF stages. The microtune circuit was intermittent after I restored the spring contact to the FM tuning knob shaft and burnishing the relay contacts corrected the intermittent problem. The 202-R microtune circuit now works reliably every time.

    It would have been nice if when these tuners were made that relays had been used which had mercury wetted contacts. Those are contacts on reed leafs that are enclosed and sealed in glass with the mercury used to provide very long life low resistance connections. The downside is that they are more expensive than is warranted in consumer products. They saw common use in telecommunications analog equipment provided to telephone companies for decades. There the expense for the best relays can be justified.

    This tuner is Serial Number 20233E, so it is an early 200-B. I have the service manuals for 30001-49999 and for 60001-69999 but it appears that the 30001-49999 manual will be close enough for most everything I might need on this chassis.

    Dave;
    Were there any significant differences between the 20000 series of FM-200-B and the 30001-49999 sequence serial numbers?

    Joe
     
  14. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Joe -- Not particularly. The biggest difference is that the 20K series used a three position Selector switch for: Mono, Automatic, and Stereo Filter, with the last position being a forced (non-automatic) stereo position. Starting with the 30K units, they added a fourth position to this switch and labeled it "Stereo". This too is a forced stereo setting, but without the sub-channel filter engaged.

    The 60K units converted from the three pole relay that switched the audio signals and Stereo Beacon (like mine), to the receiver style design using a diode matrix switching circuit to handle the audio switching, while a simple SPDT relay takes care of controlling both the Stereo Beacon lamp, and the audio matrix switching circuit.

    There were other minor changes between the various versions, but these were the significant changes.

    Dave
     
  15. audmod01

    audmod01 AK Subscriber Subscriber

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    Dave;
    Thanks for the extra information on the variations regarding the stereo switching.
    Joe
     
  16. Patrice B

    Patrice B AK Subscriber Subscriber

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    I'll have to look which SN is mine, interesting!
     
  17. mrphilco

    mrphilco AK Subscriber Subscriber

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    Congratulations, Joe, on another fine acquisition! :thumbsup:
     
  18. audmod01

    audmod01 AK Subscriber Subscriber

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    901
    Location:
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    The FM-200-B arrived shortly before 11 AM yesterday. It was packed in two boxes, so I removed the inner box and then took the unit out still in bubble wrap. Today I was determined to examine the unit in detail. I discovered that the packing was less than ideal. The tuner chassis and faceplate are in good shape, but not so the cabinet. The cabinet arrived with the right side cracked loose from the wood base and the right front piece is completely loose from the right side near the groove at the front. The left side was more intact and still glued to the wood base, but the left front trim piece is completely loose like the right side. I will have to carefully re-glue and assemble the cabinet in order to be able to use it. The metal screen at the top rear of the cabinet is not bent, but has considerable discoloration, so it will need to be cleaned, sanded and then repainted.

    The chassis is not as pristine as the photographs seemed to indicate, but I took time to clean it with some Q-tips and Simple Green plus some Goof-Off. It looked as if some of the front part of the chassis had some wood stain spilled onto it and the flywheel weight. The Goof-Off removed that well. Overall it cleaned up pretty decently. One casualty of its history is the rear 120VAC accessory outlet - it is broken away from the riveted frame that held it to the chassis on the inside. I am guessing that something had hit it from the rear when an AC plug was connected to it and it broke the socket loose and shoved it up inside the chassis. The remnants had been removed and the wires connected to bypass the missing socket. There are a few spots of corrosion which went through the plating to the steel underneath. Fortunately there are not a great number and it will be possible to clean and scrub the worst of the corrosion, then use a bit of primer and apply some Krylon satin nickel finish to stop the corrosion and dress it up. It will not be nearly as much work as some I have dealt with.

    Here are a few pictures.
    Arrival web 01.jpg Arrival web 02.jpg Arrival web 03.jpg Arrival web 04.jpg Arrival web 05.jpg Arrival Cleaned web 02.jpg Arrival Cleaned web 03.jpg
    Another plus for the day is that the frame part that NotDigital was sending arrived today in the mail, so things are going well.

    Joe
     
    Last edited: Sep 22, 2017
  19. notdigital

    notdigital AK Subscriber Subscriber

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    Glad to help :thumbsup:
     
  20. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Nice clean up Joe. No doubt you know, but a couple of quick observations:

    1. The right two vertically aligned knobs are of course reversed.

    2. The front panel indicator jewels in a L to R orientation should be OR -- GRN -- RD.

    At least the jewels are the real thing -- hope they're easy to pop out!

    Dave
     

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