Snagged a Fisher 400 - resto time!

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

  1. larryderouin

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

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    Like you said "tight as a Banjo String". I've seen them tight but not THAT TIGHT!
    Dave; I set the dial pin for Zero as it stopped on the other side around 102 to 105, not off the scale like most of them. Now it's nice and smooth and can do about 1/2 the scale spinning
    the knob now.

    Thumper;
    Put a FM DIPOLE Antenna on your list of things from Parts Express to get.
    https://www.parts-express.com/parts-express-fm-dipole-antenna--210-020 $1.95 ea.

    This one might be a good start on getting a YAGI. https://www.parts-express.com/winegard-hd-6010-omnidirectional-fm---hd-radio-antenna--210-152 It's an OMNI, so it'll work in one position and pick up all around it. If you determine it's best direction to point it, then aim for DC on one side and Baltimore should get picked up on the other without a rotator, for now.

    Will Do on the get together, I'll let Steve know to add you to the list. Let me know if you want to align the RF-IF on it. Using the KM-60 Self alignment procedure, all you need is a DMM. You can get them really close, unless you're ham handed and named Mongo. I'll bring the SG-165 and the scope and we can spend the afternoon with it.

    Larry
     
    Last edited: Aug 8, 2017
  2. Thumper

    Thumper Active Member

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    Just to be sure I have my marching orders all set:

    -redo the IBBA ground. Not bad as is but could be better.
    -swap volume pot (gravy train)
    -change out phono caps C66 and C67 - C66 is between pins 2/6 and C67 pins 1/7. Stock value was 0.01uf but I have a couple 0.022uf yellow tube deals on hand outta my parts drawer.
    -tape/aux resistor snip - R69 and R70 330k? Larry you said 68 ohm but I'm seeing 330k, tell me if I'm nutz here.
    -reverse headphone feeds.
    -FM de-emphasis tweak - change R222/R223 to 18k
    -change MPX caps C214/C221/C222 if I can get to 'em - they came with metalbone's kit but I took one look and said hell no!

    Edit - I may have some of the part #'s wrong here as I've three sets of skits for it - the correct one (hard to read) - another correct one that came with metalbone's kit (that's easier to read) - and the MPX section skit out of the early model service manual which was the only one I could find.

    Double edit - didn't realize metalbone's kit came with a late model MPX skit - I compared them and the part numbers look the same.

    Rob
     
    Last edited: Aug 8, 2017
  3. larryderouin

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

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    I let ghazzer know to put you on the list for the gt-together. Keep an eye out for a Conversation from ghazzer.

    C67-C68. Both .01. Leave the Same Value. 400V

    R69-R70. Yeah 330K. I don't know where I got 680ohms. The ones to remove are paralleled with the caps. Just cut them out leaving the caps.

    Correct manual link here....... http://www.fisherconsoles.com/non%20console%20manuals/fisher%20400%20beg%2048001%20sm.pdf

    If you run into problems get hold of me and I'll come down and work it for ya. I work cheep,,,,,cheep,,,,,cheep. Will someone strangle the canary, PLEASE!
     
  4. Thumper

    Thumper Active Member

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    Ha! 0.022 no good for the phono caps tho? Boo... don't have any 0.01's on hand... actually I have one yellow dude and I'm sure I could scrounge up another but I'd rather they match.

    I found an antenna, too. Haven't tried it but I'll check out those links tomorrow.

    Thanks! Bedtime... zzz...
     
    Last edited: Aug 8, 2017
  5. larryderouin

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

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    Don't worry about the .01's. I've got a bunch.

    Me too. Although I'm bacheloring it now. Wife went to FLA for a week. HOT DAMN! NO one looking over my shoulder.
     
  6. Thumper

    Thumper Active Member

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    Mine's got three hour training classes for work tonight thru Thursday, so I'll be downstairs slingin' solder...
     
  7. lokerola

    lokerola AK Subscriber Subscriber

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    Wow, this is a cool thread, thanks for posting all this guys. I admit, I don't know most of what the heck is going on with this tube stuff, but it's cool to see an old piece of gear come back better than ever!

    I need a good electronics book.
     
  8. Thumper

    Thumper Active Member

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    Spent most of the night so far installing Mark's volume pot/power switch. No juice. Then after some desoldering and investigation it looks like the switch is no good. I get no connection between any of the pins whether on or off. I did slap some small dabs of solder to the case in places so it doesn't wobble all around but I applied minimal heat while doing so. I emailed him, I'll see what he says.
     
  9. Thumper

    Thumper Active Member

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    I finished doing everything in my list of "marching orders" that I posted on Tuesday at like 1am... Larry I found a couple 0.01uF orange drops hiding in my parts drawer for the phono caps. Haven't tested the phono section yet though.

    I have two problems now:

    Very weak sound from the right channel when in FM stereo or FM stereo filter mode. Mono sounds fine. I'm sure I messed up something in the MPX section even though I was anal about that whole part - it IS still tight in there even if you let the module hang and work on it from the top like Larry suggested. From the bottom is pretty much impossible!

    Sirius XM into the aux/tape inputs is quieter than before, I have to crank it to like 11 O'clock whereas before it was at around 9. I thought snipping R69/R70 would make it louder?

    Also still waiting to hear from Mark about the power switch - I have it jumpered right now for testing.
     
  10. larryderouin

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

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    Let me look at my late model 400. (Gotta Dig it out of the crap stack).
    I can come over Sat or Sun and look at the MPX. No problem. I'll bring the scope and SG-165 too. Time and Day up to Da Boss (SWMBO).

    EDIT! OK yank the caps too. I just went thru the Improving the 400 thread and found the answer on page 5. http://audiokarma.org/forums/index.php?threads/improving-the-fisher-400.511867/page-5 The Tape Monitor will have 1 stage less gain than the Aux due to it's position in the line up. Doing the rest of the conversion(moving the wires around) will have the AUX and Tape Mon at the same level. Suggest reading the whole thread so you get an understanding of what the 400 is capable of. You can mix and match and only improve it.

    I'll bring some parts (resistors and a couple of caps if I have them).
     
    Last edited: Aug 11, 2017
  11. Thumper

    Thumper Active Member

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    Larry i'm way busy this weekend, but I got the MPX problem sorted, I soldered one end of R223 to the wrong place. Duh! FM is sounding pretty fantastic right now...

    So then I snipped those other caps on the AUX inputs (C71 and C72) - Sirius into the aux inputs is still SO much quieter than FM. I know my Sirius thing has low output (and I already screwed with the settings to turn it up all the way).

    That 400 resto thread - I think I've read it five or six times, heh.
     
  12. larryderouin

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

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    Make sure the Tape Monitor switch is DOWN. Cycle it a few times.

    OR put the inputs to the Tape Mon inputs and throw the switch UP. It may be slightly lower or maybe the same. May end up doing the rest of that mod, although you really shouldn't have to.

    Remember I'm retired so anytime you want to get together, even during the week is usually good for me. Ain't got anything else to do, except listen to my FISHER's. LOL.

    I got one of those Winegard Antenna's I linked above. Gonna put it up later today and see what's up. You got RG-6 cable? When I come down next we can run it outside and see how it does in the fringe areas.
     
    Last edited: Aug 12, 2017
  13. Thumper

    Thumper Active Member

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    I cycled the switch, didn't make any difference. I guess I just have to turn it up. Will be louder thru Klipsch's vs. those Minimus's too.

    I found a dipole like you linked earlier in my junk box, I'll try it later if I get a chance. Let me know how that winegard works out.

    Funny, I'm listening to my kitchen rig right now (8080db) and 100.7 comes in clear (also with a crappy antenna). I can't get 100.7 downstairs on either the Fisher or the Dynaco rig. I need a real antenna up on the roof.

    RG-6? Is that coax? I have some, not sure how much though.
     
    Last edited: Aug 12, 2017
  14. larryderouin

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

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    RG-6 is Coax. I put up the Winegard, and had it hooked to the KM-60. 100.7 comes in now at a 3.5 vs. 2.5 earlier. 100.3 now comes in just over 3.0 as does DC101. I've got to fine tune it tho. That won't happen until wednesday when I can get old lady to watch the meter while I'm on the roof. Gonna break out my 400 and check it too.
     
  15. Thumper

    Thumper Active Member

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    I got my new IF/RF tubes today - changing out V2 made little to no difference (old V2 was the stock one that tests iffy) - other than the fact that it throws off the tuning by a bit. That's weird! Larry hooked me up with an NOS V3, and now I have spares for all.

    So then I slapped my dipole up on the shop ceiling for grins - almost all stations come in better but I could get 105.7 pretty good with that little Phillips thing before and now not at all. Maybe if I tweaked it I could pull it in but I just kinda stuck it up there.

    Larry keep me posted on your antenna progress!

    I'm not usually a fan of loudness switches, but into these little realistics it's actually pretty cool! Much more ass down low. I just wish Mark would write me back about this funky switch.

    Only other thing bugging me is the aux/tape inputs seem really quiet. Did the cap and resistor snips between those inputs and the tape monitor inputs which, in theory, shouldn't have affected anything but I dunno? FM is as loud at zero volume as XM is at 11 Oclock?
     
    Last edited: Aug 13, 2017
  16. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Thumper -- The apparent high gain factor when listening to FM in any of its settings is due to the high output of the FM tuner section (which is easily over a volt) and is a common observation with Fisher receivers. The FM circuits operate into what is effectively the same gain level as that presented at the Aux input jacks, which if all is well, requires about 280 mV for the receiver to develop full power output. Some of today's personal digital sources do not develop this much output, so the disparity between them as presented at the Aux input, and that of FM section, will be significant as noted in the different volume control settings required for a similar sound level. The sensitivity at the Tape Monitor inputs is even lower, approaching nearly .5 vac to produce full power output. These sensitivity levels were entirely appropriate for the few sources that existed back in the day, but can be inadequate for some digital sources today. Also remember that FM back in the mid 60's was nothing like it is today. The idea of 100% modulation nearly 100% of the time was not even possible back then, let alone desirable, so FM as a source is much "louder" today than it used to be. This by itself adds notably to the disparity you note as well.

    Somewhere there is a thread I did (either as an actual thread or as a response in someone else's thread) wherein I show how to "electrically move" the Tape Monitor switch and its inputs, so that the Tape Monitor input will offer the same input sensitivity as that of the Aux input. It may even be in the "Improving...." thread I did.

    Removing the cap and resistor did nothing to change the ultimate sensitivity of any of the inputs. What is did was to remove the interaction that originally existed between the Aux/Tape Play inputs and the Tape Monitor inputs -- a feature that allowed the receiver to operate to best advantage when using a true 3 head tape deck, which few if any folks do today, if they even know what one is. That's not meant as a slam on anyone. It just means that it is a technology that is long gone today.

    V2 is the local oscillator for the FM RF section. It is not uncommon for different examples of the tube to slightly change the dial setting, but the effect has little significance in actual use.

    Dave
     
    Last edited: Aug 13, 2017
  17. larryderouin

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

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    Rob; I saved Dave's directions so I have the rest of the Aux/Tape Mon wiring change. This will allow the Tape Monitor to sound off at the same level as the Aux even tho they are separate still. It's not that hard and takes about an hour or so.

    BTW: Did I leave my probes at your place with the CD for the scope? If so hold on to them and I'll get them next time I'm down that way. Go ahead and try them out on yours until then.

    Larry
     
  18. Thumper

    Thumper Active Member

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    Dave, great response and understood on all points. So, let me ask what is possibly an unorthodox question - rather than trying to increase the gain from the the aux inputs, is there a way to lower the FM volume? I would think just adding two resistors inline or to ground somewhere would do it? This one is still somewhat loud even with the volume all the way down (and I still haven't heard back from Mark, dammit! The switch clicks on fine but turning off just doesn't feel right).

    Larry, no probes here. Where's that plastic pouch you had? I watched you pack up. Check the Sonoma? Under the pass seat? I might want to do the rest of that mod but for the duties this one will pull I'm leaning toward naaaah. For now.

    Rob
     
    Last edited: Aug 14, 2017 at 12:27 AM
  19. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Rob -- Does your 400 still have the original factory volume control installed?
     
  20. cantonkid

    cantonkid AK Subscriber Subscriber

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    i just picked up a 400 also , i am very impressed with the help in this post ,sure wished i lived closer also to some tube people as i know chit but want to learn.
    this thread sure has me thinking about my 400 ,the wood case wasn't ordered with it new as i am the second owner
    Don
     

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