Author Topic: Re-capping advice needed for Magnavox Provincal Serenade  (Read 1497 times)

SteveJB

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Re-capping advice needed for Magnavox Provincal Serenade
« on: December 15, 2014, 10:58:21 AM »
I noticed that in my Magnavox Provincal Serenade there are a lot of ceramic caps.  Having only restored 30's sets until now, I dont see many of these.

Is it ok to leave them in along with the micas and just change out the paper caps, E-caps and out of tolerance resistors?

Steve

AstroSonic100

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #1 on: December 15, 2014, 12:08:41 PM »
The ceramic disc caps and micas can stay.  Micas are used in the front end of the tuner and replacing them will require the tuner to be re-aligned.  Not an easy job.  Both those type of caps rarely go bad.  The paper caps and E caps will need to be replaced as well as out of tolerance  resistors.
 
Ray

Consoleman

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #2 on: December 15, 2014, 12:19:08 PM »
Since you need to desolder one end of a resistor to check it, I figure you might as well just desolder the other end too and replace all of them. That's what I did to my Amp-150 since there were some well out of tolerance.
Mark

Pat L

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #3 on: December 15, 2014, 12:53:32 PM »
I check resistors in circuit as they should never read higher but may read lower in circuit. Since carbon resistors drift higher with age this seems like a logical approach to me. I never change ceramic caps unless there are obvious defects, same goes for mica. I always change all small electrolytics and paper caps. I often leave the can caps if they are in good working condition.

Sometimes when I customize amps I will replace ceramic coupling caps with film caps. Pat

Larry H

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #4 on: December 15, 2014, 01:23:38 PM »
Just replace all the wax caps in the amp and tuner, and also the electrolytics.  The cap replacement procedure is identical to restoring 1930s radios...replace the wax caps with 630-volt axials.  I used to restore antique radios, so when I went to radio-phonographs it was a breeze.

I just check resistors for continuity with my multi-meter... it is rare I have to replace one unless it is open or causing distorted sound.........
--Larry

Harbourmaster

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #5 on: December 15, 2014, 01:57:15 PM »
One thing I have noticed with the Maggies, and I seem to recall Greg mentioning this as well, is that the resistors drifting out of spec can really play havoc with the "sound quality" of the restored unit. 


I now make a habit of checking ALL the resistors in the Magnavox amp's and tuners, and anything that measures more than 5% out of spec gets replaced with Metal Oxide.



-- Aloha, Ken

No Console Left Behind!

SteveJB

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #6 on: December 15, 2014, 03:47:13 PM »
Thanks guys!  I am getting parts now.

Steve

electra225

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #7 on: December 15, 2014, 06:33:41 PM »
I don't even pull the back on a Magnavox stereo without having a drawer full of caps and resistors on hand.  So far, I have replaced about 80% of the resistors in a typical amplifier.  I don't even check the 220K grid resistors anymore.  I just changed them automatically.  I shotgun the caps and resistors, then power up with a Variac and dim bulb and fix whatever issues arise.  Normally, all is well at startup.  I like using 1% tolerance resistors.  Good luck.
If it ain't broke, call me.  I can break it....

SteveJB

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #8 on: December 15, 2014, 07:50:11 PM »
What about those 5 and 10 W wirewound resistors?  Are they an issue with these?  I never change them in the older sets unless they are open. 

Pat L

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Re: Re-capping advice needed for Magnavox Provincal Serenade
« Reply #9 on: December 15, 2014, 08:10:07 PM »
I never change them unless there is obvious damage or they're open.