202-R Arrived

Discussion in 'Fisher' started by audmod01, Jun 27, 2017.

  1. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Over the last several days I have been dealing with a strange AM problem with the 202-R. The FM sounded fine on all stations or when fed to both channels simultaneously (FM only function). When AM only was selected the AM audio coming out of both channels was strong and full bodied. However if I selected one of the AM-FM functions, either phase shifted or normal the audio was thin and reduced in volume. I measured DC voltages on the AM 12AX7 tube and everything was normal. I could see some slight differences in the AM audio at the output of the normal and phase shifted output coupling capacitors. So I changed the two output coupling capacitors. I also changed the one on the output of the FM 12AX7 too. Still the audio when operating in the AM-FM mode was thin (lacking in bass) and reduced in volume on the AM dedicated output. This issue developed while I was swapping the AM and FM Level meters around. I kept wondering if something I had done during that exercise had caused it.

    Finally I began to suspect the audio cables I used to the interface of the preamp to the audio system I was listening through. I swapped the left and right channel audio cables to the preamp and the problem went away! One of these two cables either has an open ground or a poor signal lead connection inside. I realized that I had moved the tuner about when I was looking at the two meters and evidently a poor connection developed inside one of the audio cables. Fortunately these two cables are the type that can be repaired. Both ends of each cable has a screw-on shield cover and can be removed to gain access to both ground and signal conductors to rework them.

    This is the second time I have been bit by defective audio cables recently. The first instance was on the Electra 440/490-T combination with a bad dual audio cable that was brand new. Now this issue with older cables that have seen frequent use over the years.

    So now the 202-R is fully functional in all modes and works normally with great audio! I can button it back up and concentrate of building up the MPX-65 that I plan to convert to WX functionality and use two 12AT7 tubes and one 12AX7 tube in it. I have two small power transformers I ordered from AES that will provide both HV and filament voltages for the MPX circuitry separate from the power transformer in the 202-R. The MPX sub-chassis will be built into a Bud aluminum box that can either be attached to the back of the 202-R or lie alongside it in a custom cabinet. I will work to provide a way to auto-switch when the MPX circuitry is functional. There is a lot of planning ahead.

    Joe
     
  2. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    One item I noticed about the 202-R is that on the left side of the chassis behind the area with the FM tuning knob, there is a thin plated steel plate attached by two screws to the side of the chassis. There is no critical circuit in that area that I can see. The FM tuning knob does have the contact behind it that senses the touch of a person's hand to turn off the Microtune AFC circuit. I am wondering if the steel plate was added to help avoid sensing nearby objects that might mess with the operation of the Microtune circuit. Dave mentioned that it operates by picking up stray 60Hz energy in the air that is intercepted by the human body, amplifies that and uses the result to trigger the AFC defeat relay.

    Joe
     
  3. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Location:
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    That's exactly what it's for Joe.

    Dave
     
  4. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Dave;
    Suspicion confirmed! I do find that if I move the tuner around to different spots in the room that the Microtune sensitivity sometimes needs to be readjusted with the control on the back.

    Today I made a new FCC Part 15 label and a GOLDEN CASCODE label to dress up the FM Front End cover. I have been doing some more cleaning. There is still a lot to do such as tube shields and the front knob outer brass rings but it is slowly looking better. That thin plate near the FM tuning flywheel and knob shaft was hopelessly corroded on both sides. So I carefully sanded it with 220 grid sandpaper and then primed it and painted it with Krylon Brushed Nickel paint which looks so much like the typical plating used on most USA chassis that it is all but indistinguishable. I took a few pictures to show how it looks so far.
    Cleaning web 01.jpg Cleaning web 02.jpg Cleaning web 03.jpg
    Joe
     
  5. vendo81

    vendo81 AK Subscriber Subscriber

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    1,493
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    Nice work Joe! You've been amazingly thorough with this 202-R. I'm sure when finished it will be one of the best performing Fisher tuners out there :)
     
  6. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    8,842
    Location:
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    Super job Joe. How you do bring Fishers back with more than both feet in the grave!
     
  7. larryderouin

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

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    It's easier if he don't have any banana peels near the hole.
     
    arts likes this.
  8. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Cleaned and polished the knobs this morning. Here is a picture.
    Knobs Polished web.jpg
    Were the small pointing arrow heads on the knob end caps filled with white paint or are they supposed to be brass?

    Joe
     
  9. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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  10. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Dave;

    OK Thanks. Now I know what I need to do. Probably can use toothpicks and chrome polish to make them visible again.

    Joe
     
  11. larryderouin

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

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    On my TA-600 they look brass colored, but could be a beige or off white color. I really can't tell. I would think Fisher did them in Brass color to match the ring.
     
  12. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Larry;

    Yes, I think that the maroon color surrounding the arrowhead is paint applied over a brass cap underneath. That way the brass could show up as the arrowhead. Otherwise they would have been similar to the solid brass bright knob caps on the later models with the - or dash line on them.

    Joe
     
  13. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    As it turned out I was wrong! I used some chrome polish in the depression that is the arrowhead pointer of the knobs, scrubbed with a toothpick and it rubbed away the color completely down to the maroon plastic. So the real answer is that these are painted on. The outer trim is apparently a brass ring and the face of the knob is just plastic after all. Under a good light and using a magnifying glass I could see the metallic pigment of the original paint. So I pulled out my Folk Art #660 Pure Gold metallic acrylic paint (from arts & craft store) and used a toothpick to pick up a small amount of the gold paint and apply into the arrowhead depression. Then, although it runs over the edge of the depression, I just used my finger to wipe across the area and leave enough paint to fill the depression and be visible. The knobs are drying now. Here is a picture of the result.
    Knob Arrowhead Renewed web.jpg
    I would say that if this is not satisfactory as a visible aid to your eyes that using a white acrylic paint would probably be a better choice. Since Dave and Larry remember the knobs having the brass look, I went with the gold metallic paint.

    Joe
     
    Last edited: Aug 17, 2017
  14. larryderouin

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

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    Nice Job JOE. You wanna do mine??:D:p:biggrin:
     
  15. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    One thing that I have noticed ever since I had eye cataract surgery is that it is really difficult for me to read magazines in which a page is printed as white text on black background. It does strange things to my vision. The best way to see and read text is as black text on white background. I wonder if Fisher realized the little arrowhead pointers on these knobs were not easy to see and decided to change to the bright knob caps for their later products. Small ridges on the side of the knobs were added that lined up with the dash pointer on the brass caps and were nice aids to people who had poor vision. One of my pet peeves is the products that began to show up in the 1980s and into current times with black faces and white lettering. Some people like them, but to me they look cheap and tacky in addition to being difficult to read. Give me a vintage Fisher, H H Scott, Marantz etc. with a nice bright metal faceplate any day.

    Joe
     
  16. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    I cleaned all the rear connectors including the antenna connections plus the RCA sockets. I had bought some black outdoor enamel paint at an arts & craft store which I used to renew the serial number on the chassis. I used a straight pin to apply very small amounts of the paint and was using a magnifying glass to help me spread the paint. It is tedious work, but I managed to get it done. With the back of the chassis cleaned and polished it looks good from the back now. I am still looking for a method to work on cleaning and polishing the tube shields. I may be able to find some rubber hose that will fit inside the shields and be able to use a screw or other item that can then be inserted into the hole of the hose center and then into the drill chuck.
    Here is how the rear of the chassis looks now.
    Rear panel cleaned web.jpg
    In the meantime my laptop computer is nearly 7 years old and is having problems. I need to do a save to my backup drive. I think the cpu is overheating as the fan seems to slow down and the cpu begins to show 100% usage and almost nothing can be done except to shut it off.

    Joe
     
  17. fred soop

    fred soop Super Member

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    1,765
    If you have a ceiling fan, try running it on the lowest speed. In my case, it moves just enough air that the computer stays quite cool. Otherwise, it does get warm but not too warm as the fans do not ramp up.
     
  18. larryderouin

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

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    Joe; If you have a compressor, take the 30psi nozzle and blow compressed air into the exhaust to force the dust and dirt out thru the intake. A good long blast should get a lot if not most of it out. This works on my 15 year old Dell. Have to do this about every 6 months or so now. Same problem, it heats up and then you get 100% load on idle.

    Larry
     
  19. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Larry and Fred;
    Thanks for the suggestions. I plan to do the compressor air method sometime today. I did that last year some time and also had to replace the keyboard in it. This time I notice that the internal fan seems to slow down, so I plan to also order a new fan. After all, this laptop is nearly 7 years old - a long time for a fan to keep going.Fortunately I have this older tower computer running XP-Pro that I can fall back on. Unfortunately it does not have Adobe Photoshop installed on it. It does have a HP graphics program where I can do a few things though. I probably need to look for a new laptop anyway.

    I had both a PET scan and a thin-slice CT scan of my head and neck this week. My surgeon wants to be sure that there is not some more cancer lurking somewhere. He was pretty sure he got it all, but does not want to take unnecessary chances. I have had so many X-rays over the years that I should be glowing in the dark.

    All the best to everyone!

    Joe
     
  20. audmod01

    audmod01 AK Subscriber Subscriber

    Messages:
    898
    Location:
    Tioga, TX
    Vendo81 asked about the LED festoon lamps used in my 202-R, so I measured them. The LED lamps installed are 1.215" tall and the OD of the end-caps is about 0.16", however, the end caps are really thin and are deformed from plugging them into the connectors (slightly flattened on two sides) so the measurement of OD is suspect. The connector opening they plug into is 1.4" tall. The measurements were made with my dial caliper. The connector opening looks very similar to the opening that was in the Electra VI that I have been working on for my granddaughter. The connector housing is a medium to dark brown plastic body with copper coated spring clips inside. The could easily be cracked if lamps with too large an OD end caps are forced into the clips. That thinness of the LED lamp end-caps may be the only thing that kept the connector housing from being cracked. So caution needs to be exercised when plugging these LED festoon lamps into the existing lamp sockets to avoid cracking the plastic body of the socket housing.

    I suspect that the 101-R and R-200 tuners may have used the same festoon incandescent lamps. If someone here has a 101-R, R-200 or 202-R tuner which has OEM incandescent lamps in it, please measure the lamp overall length and the width of the end-caps. The glass on the incandescent lamps cannot be any larger in OD than the end caps without the potential of cracking the body of the socket housing.

    The LED lamps that I used to replace the #47 lamps behind the jewels also have very thin bayonet base metal. They are so thin that it is possible to bend them with your fingers. I have saved a few #47 lamps that were burned out from various equipment and I have made my own naked LED lamps in the past. I cracked away the glass and removed the center lead by unsoldering from the base - just heat the solder tip and the remains of the center lead can be pulled out while the solder is molten. Leave the lead that is soldered to the outer base cylinder in order to have a lead to solder to. I used some medium intensity LEDs with a suitable 1/4 watt dropping resistor to limit current through the LED and used some sleeving to insulate the resistor and center conductor going to the led. The other LED lead can be left bare if desired or sleeved too. Solder the other LED lead to the wire that is soldered to the outside cylinder of the lamp base. The completed assembly will have to fit into the available space, so watch your dimensions.

    If very many of the LED Festoon lamps have the very thin end caps like mine, it may also be a good idea to save 3AG style blown fuses to rob the end caps and make modifications to current replacements if needed. On the other hand, if the end caps are thin and deform while installing them, it may help avoid cracking the lamp connector housing.

    Joe
     
    Last edited: Aug 20, 2017

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