Author Topic: Magnavox 59-23-10 Preamp/Tuner Schematic  (Read 552 times)

typecrazy789

  • Newbie
  • *
  • Posts: 14
    • View Profile
Magnavox 59-23-10 Preamp/Tuner Schematic
« on: February 20, 2019, 10:37:17 PM »
I came into an (I think) 1962 Magnavox Danish Contemporary and, while it has the 8602-10 amp which the schematic is readily available for, the 59-23–10 preamp/tuner schematic I’ve been unable to locate. Is there a good source for this? Any help is appreciated!

electra225

  • Hero Member
  • *****
  • Posts: 3052
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #1 on: February 22, 2019, 11:29:51 PM »
I have a schematic here for the 59 series tuner.  Do you need a copy of the schemtic or is there a question you have?
I don't need Google.  My wife says she knows everything.

typecrazy789

  • Newbie
  • *
  • Posts: 14
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #2 on: February 23, 2019, 01:49:07 PM »
I need to eventually recap the unit (along with the amp) in my console and as we're currently using it daily I was hoping to get a list of at least the filter caps from the schematic to go ahead and order what I need as to not have to dismantle it until I'm ready to do the work. It's humming enough I can't let it go a lot longer but not so bad we can't enjoy it (yet).

Bill

  • Hero Member
  • *****
  • Posts: 1149
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #3 on: February 23, 2019, 07:45:10 PM »
I hate to tell you this, but, if it's humming you should not be using it at all.  You are at the risk of blowing your power transformer.  If that goes you will have a lot more to rebuild than you bargained for.   Getting a schematic is a good idea no matter what, and it is a big help when it comes to ordering parts.  Good luck, but please stop using it until it's at least recapped.

Bill


electra225

  • Hero Member
  • *****
  • Posts: 3052
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #4 on: February 23, 2019, 08:25:50 PM »
PLEASE don't operate your stereo until it is serviced.  That humming sound you hear is not good.  I'm not going to tell you, like some would, that you are going to set your house on fire or any of that nonsense.  But you could damage hard to find, expensive or unobtainable components.  Have it repaired properly before something unfortunate happens.


Your tuner should have a double 30uf @350 volt cap in a can on top of the chassis.  There are two 25uf @ 50 volt cathode bypass capacitors.  Most of the Magnavox tuner chassis had a double 20uf @350 volt cap as well, but I don't see it on the schematic at this moment.  There are two 470 ohm cathode bias resistors that are known to burn and could cause your hum.  I'd replace those.  IIRC, they are 1-watt units.  The amp has a 40uf, 40uf, and a 20uf @ 450 volts in the can on the chassis.  There is a 30uf @50 volt cathode bypass cap and a 100 ohm, 1-watt cathode bias resistor that I would recommend you replace.  Measure R29 and R36 for value and replace if they are over 20% out.  These are the grid resistors for the 6BQ5 audio output tubes.  I would replace them anyway with 1% metal film resistors, but that is your choice.  Then there are a number of paper caps that should all be replaced.  Measure all the resistors while you are replacing caps.  I have found 80% drifted high.  Last, but not least, install a fuse in the primary of the power transformer in the amp chassis.  A 1-amp Slo-Blo should work fine.  Do this whether you think it makes sense or not.  Ask Bill about the value of a fuse........ ;)


Since you have a hum, I would not reuse the rectifier or the audio output tubes.  Buy new JJ's or Electro-Harmonix and be done with it.  NOS tubes are no better than the ones you have now.  Be sure you test those pesky 6EU7's for shorts.  Good luck.
I don't need Google.  My wife says she knows everything.

electra225

  • Hero Member
  • *****
  • Posts: 3052
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #5 on: March 03, 2019, 11:52:33 AM »
Has there been further activity on this stereo?
I don't need Google.  My wife says she knows everything.

typecrazy789

  • Newbie
  • *
  • Posts: 14
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #6 on: March 04, 2019, 04:29:06 PM »
Have barely touched it since I last posted having been gobsmacked lately with work - but I did order the parts. Hope to have a day soon to do the repairs and get it going safely again!

electra225

  • Hero Member
  • *****
  • Posts: 3052
    • View Profile
Re: Magnavox 59-23-10 Preamp/Tuner Schematic
« Reply #7 on: March 04, 2019, 05:44:36 PM »
Keep us updated with your progress.  If you have questions, we're here to help!   :)
I don't need Google.  My wife says she knows everything.