Super Find: McIntosh MR 78

Discussion in 'McIntosh Audio' started by gssound, Jul 3, 2018.

  1. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Well, the thrifts aren't totally dead: today, I couldn't believe my eyes when I found an MR 78. Plugged it in at the store, and was glad to find it turned on, all the lights seemed to work.

    To be honest, I had no idea what kind of unit it was, only that it was McIntosh. I have a small collection of vintage integrated amps, and know a little bit about them, but not too much about this. Certainly nothing about this unit. Serial # AD3 831

    Overall, its in VG+ physical shape with wood case. A few marks on the case, but the unit inside it beautiful. The front panel is okay, but it is missing the silver rectangle that around the dial. There is some crackling (crazing?) look along the bottom of the front panel. Not cracks, just perhaps its beginning to seperate from whatever its attached to.

    I don't have a variac, but I just plugged it in and let it sit for a while when I got home while as I tried to see if it would give some sound. I went to look for speakers and an antenna, and when I returned - WHOOPS - quite a burning smell. More like old burnt wood/wet cardboard, rather than an acrid electric burn smell. Anyway, I unplugged it immediately. It didn't feel overly hot, and the smell seemed to emanate mostly from the top rear left hand area.

    So, what do you experts think? Perhaps it was just dust burning off as it heated up for the first time in who knows how long, or maybe its worse? In any case, I'm still very satisfied considering what I paid.

    Not to be completely green, but I don't really get how this works: do I just plug speakers into this, or does it need to go into a power amp? What can I do with this beast? Shall I pop the top and dust this sucker out?

    I'll see if I can get some pics.

    Thank you for reading! I look forward to discussing my unit more.
     
    ossidian likes this.

     

    Please register to disable this ad.

  2. 62caddy

    62caddy Trust but verify Subscriber

    Messages:
    9,224
    Location:
    NEPA
    Tuner>Preamplifier>Amplifier>Speakers. :)

    Should not be operated further until it is checked by a qualified tech. A desirable model and it should ideally be entrusted to those familiar with those familiar with McIntosh only. Can almost guarantee the service bill will be many times what you've paid. May want to simply list it on the auction site "AS IS - PARTS OR REPAIR ONLY", along with your direct experience as detailed above. If you go that route, for heavens sake make sure to obtain the proper McIntosh packaging for the unit from Audio Classics - which again, I wouldn't be surprised if even that cost more than what you paid for the MR78 at the thrift store. Unfortunately there is no other alternative to ensure safe transit.
     
  3. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Jul 5, 2018
  4. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Thank you for your input.

    I suppose if I wanted to, I could plug it into the aux of an integrated amp. Right?

    I hear your warnings! There is a wonderful McIntosh tech in my neck of the woods, and perhaps I'll bring it to him. Whether, or not, I want to invest that kind of money into a dedicated tuner is a different story. I do love FM, but - as I'm sure you all know - the available options are getting thin, even here in the NYC area.

    I still kinda want to dust it out and try it again though... :crazy:
     
  5. musichal

    musichal poet emeritus Subscriber

    Messages:
    10,708
    Location:
    Norman OK
    Yeah, if you can open it up and look around, maybe you'll get lucky and find a burnt roach, of one sort or another.
     
    trainbuftony and LPplayer like this.
  6. grillebilly

    grillebilly Empty Head Subscriber

    Messages:
    15,703
    Location:
    Fairfax VA
    I was listening to this online last weekend. If they were around me I would actually listen to music on the radio.
    https://wfmu.org/
     
    Matte Grey and gssound like this.

     

    Please register to disable this ad.

  7. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Well, there are plenty of great stations actually. It's just different. Love WFMU and I'm always complaining about not being able to tune it in!

    The MR 78 might cure my ills!
     
    grillebilly likes this.
  8. kevzep

    kevzep Its all about the Music Subscriber

    I think there are some tantalum caps in these Tuners, I'd hedge a bet one those has exploded as they do...but you really need it gone through, well overdue for a visit to rehab...

    The MR78 is a great tuner, I love mine, but not as much as the MR80, although its close between the two.
     
    gssound likes this.
  9. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    I know, I know, don't turn it on again!

    Just one last time to get the panel as the lights go down here on the east coast. The panel cleaned up pretty nicely.

    Where would I buy the rectangular piece that goes around the display?

    [​IMG]

    Smells like an old campfire, but it looks phenomenal!
     
    Last edited: Jul 5, 2018
  10. kevzep

    kevzep Its all about the Music Subscriber

    Oh if its a tantalum, all bets are the damage is done!!

    get it sorted though, when running properly, you'll be picking up stations you never knew existed!!
     
    gssound likes this.
  11. John James

    John James "Bob's your uncle" (Stolen) Subscriber

    Messages:
    8,151
    Location:
    Piney Flats, Tn.
    Fix it. If you don't like it you can get your money back by selling a great unit.
     
    gssound likes this.

     

    Please register to disable this ad.

  12. Yamaki

    Yamaki Not For Hire Subscriber

    Messages:
    3,858
    Location:
    Hillsboro, Oregon
    I'd send it to Audio Classics in New York to have it checked out, repaired and returned to spec. Audio Classics will also have parts if you want to replace pieces and parts.

    Congrats on the find.
     
    gssound likes this.
  13. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Thought I would do some cleaning and try to blow out any dust to see if the smell subsides. While I'm in there, I'll do a little Deoxit on the pots. Also, cleaning the knobs and the glass. I took the bottom off, but can't figure out how to get the cages off of the top. Help! What screws are holding them in; I don't want to unscrew anything I shouldn't.

    Thought you might like a few pics: lots o handwritten notes in there. Looks like a '79, think that's the year?

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Jul 5, 2018
  14. kevzep

    kevzep Its all about the Music Subscriber

    Get the cages off what? They are a bit fiddly to take apart the MR78. I had mine apart quite recently, perhaps post some pics of what you are trying to do and we can guide you through...Don't power it up, its still got the ROE caps in it, you really need to get it away to get sorted.....
     
  15. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    2,112
    Location:
    France
    Hello gssound
    1) don't give your MR78 to someone who never saw one for repair before
    2) I think your multi cap fail in the power supply but I don't have the unit in front of me, so I can't be sure
    3) tantalum cap (green drop ) are probably gulty too but again only one experienced tech can put his finger in it ! one bad tantalum cap is enough to get smoke over there (MPX PCB)
    4) the bezel (missingf on the front panel is obsolete (at factory) since a long time , you can ask AC just in case of ....
    5) AD3831 from 1979 ?
    AD mean that this is the first serie produced a long time ago , and 1979 is perfectly the period of production of this serie . AD9355 is the last one who come in Europe from this serie and it was the 15th march 1983 !
     
  16. jlovda

    jlovda Things I loved from the 60's and 70's Subscriber

    Messages:
    3,425
    Location:
    NE Ohio
    Funny thing about a bargain. The guy went to GW and found a $10 (a wild guess) diamond in the rough, that will now cost him hundreds of dollars in proper cartons, UPS shipping and AC parts and labor to bring it up to speed. There is even a hassle factor of getting rid of it for $100 on Craigs List. It was probably sitting on the GW shelf for a reason.
     
    slimpikkins and stereocuuple like this.

     

    Please register to disable this ad.

  17. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    I figured out how to get the "cages" off of the top: found the four screws on the bottom.

    Dusted everything throughly, gave a quick Deoxit, and I'm letting it run...about 20 minutes so far.

    No smell, so far...:)
     
  18. onwardjames

    onwardjames Hoardimus Maximus Subscriber

    Messages:
    15,672
    Location:
    Kentucky
    Why can't I see the pics? Great score.
     
    stereocuuple likes this.
  19. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Pre-Dusted:

    [​IMG]
     
    Last edited: Jul 5, 2018
  20. gssound

    gssound New Member

    Messages:
    38
    Location:
    New Jersey
    Well, going on 4 hours with no return of the burning smell. I think it was the dust. Now to try and get some signal out of this thing! I only have a cheapo antenna with the two spade style connectors.

    Can I plug this into the aux of another integrated amp?

    As you know, the bezel is missing, but I took some time to really work on the glass and get that cruddy tape residue off. It looks awesome! Aside from the bubbling, it is shiny and clean.

    [​IMG]

    [​IMG]



    Knobs are soaking...
     
    Last edited: Jul 5, 2018

Share This Page