Author Topic: Magnavox Concert Grand remote  (Read 2566 times)

Brun

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Magnavox Concert Grand remote
« on: November 12, 2014, 08:56:42 PM »
I have a '59 Magnavox CG.  The remote motor didn't work so I took it out years ago.  Recently, I took it apart and cleaned the armature and low and behold it works again.  The problem is it "races" to fast up and down.  It goes from o to hi volume in about 3 or 4 seconds.  Shouldn't it move slower than that?  Did I lose a resistor or something that comes off the volume motor?  Any help is appreciated!!

Pat L

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Re: Magnavox Concert Grand remote
« Reply #1 on: November 13, 2014, 11:27:59 AM »
Hi Brun, welcome to the group. That's an interesting problem you're having with your Concert Grand. I have not encountered the problem personally, nor do I know how fast the volume should change. Perhaps one of our members can weigh in on that. In the Download Center we have two factory service manuals for your CG. Both have the remote system schematics. Perhaps comparing the specified resistor values to the actuals in your unit you will find the problem.

I have the same CG that you do but I only recently acquired the original remote and have not calibrated it to the console, thus I don't know how quickly the volume change should be. Pat
« Last Edit: November 13, 2014, 12:55:34 PM by Pat L »

electra225

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Re: Magnavox Concert Grand remote
« Reply #2 on: November 13, 2014, 12:32:31 PM »
Perhaps I have misread, but I do not see a "specification" for how long the volume control should take to go from minimum to maximum.  Like Pat, I have not tested the Phantom Control on my '59 CG, so I am not familiar with how long it takes.  A suggestion, one based on logical reasoning, is to compare the speed of the volume control to that of the tuner.  If these two controls operate at similar speed, I'd think that was normal.  I don't see anything in the circuit that would control the speed of the motor in any case.  All the Phantom Control amplifier does is to act as a switch and control circuit for the solenoids and motors in the tuner.  It does not necessarily control motor speed.  Three or four seconds is a fair amount of time.  How long does it take to do it manually? 


Another thought, not intended to sound harsh, is this.  We should probably be happy that these Phantom Controls work at all after all these years.  All the information I have seen is geared more toward service "in the field" when these instruments were newer.  There are several items that are serviced " by faith" rather than by specific instruction.  These old instruments were never intended to be in existence 60 years hence, being loved and restored by another generation.  Good luck.
I'm great at multi-tasking.  I can listen, ignore, and forget all at the same time.

Brun

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Re: Magnavox Concert Grand remote
« Reply #3 on: November 14, 2014, 08:56:07 PM »
The volume control and radio search control motors are completely different so comparison would seem irrelevant.  My volume control goes fast enough that you are not able to adjust the volume reasonably.  One touch of the remote and it goes from no volume to over half way.  I don't believe it should go that fast. 

electra225

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Re: Magnavox Concert Grand remote
« Reply #4 on: November 15, 2014, 04:52:41 PM »
I still don't see anything in the schematic that controls how fast the volume control should work.  I have not used the Phantom Control on my CG yet, so I don't know how fast it works.  Good luck.
I'm great at multi-tasking.  I can listen, ignore, and forget all at the same time.

neali

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Re: Magnavox Concert Grand remote
« Reply #5 on: December 16, 2014, 01:50:03 PM »
I can't find the schematics. Electra, could you post a link?

electra225

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Re: Magnavox Concert Grand remote
« Reply #6 on: December 16, 2014, 06:28:53 PM »
The schematic for the CG is in MO, but I think it is available on this forum.  Go to "Downloads" at the top of this page.  Click on "Magnificent Magnavox", then "Schematics".  The last one listed is "Concert Grand 1ST800F" That should get you pretty close.  Sorry I could not be more help.  You are familiar with my computer skills.   ;)
I'm great at multi-tasking.  I can listen, ignore, and forget all at the same time.

neali

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Re: Magnavox Concert Grand remote
« Reply #7 on: December 17, 2014, 08:25:48 AM »
The schematic for the CG is in MO, but I think it is available on this forum.  Go to "Downloads" at the top of this page.  Click on "Magnificent Magnavox", then "Schematics".  The last one listed is "Concert Grand 1ST800F" That should get you pretty close.  Sorry I could not be more help.  You are familiar with my computer skills.   ;)

Got it, perfect. On page 4 is a simplified schematic of the volume control circuit.

http://vintagehifi.net/index.php?action=dldir;sa=details;lid=14

I do not see any components that could adjust the speed. I am unfamiliar with reeds but dimly recall that they tune frequency not current. If the 150 ohm resistor in series with the motor, the one with the vertical orientation, not the two with the horizontal orientation, were increased in value, the motor speed might be slowed. This is a question for Randy Bassham. Or repair tech, but that is not going to happen.