Author Topic: Magnavox AMP 175-77  (Read 592 times)

tdoades26

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Magnavox AMP 175-77
« on: January 25, 2017, 01:40:00 PM »
So I have Magnavox 1st234 with an amp 175.  It has been recapped and worked perfectly for several months after the recap.  Recently after it has played on phono, tape input, or radio it will get bad static like distortion in the speakers.  Usually it plays perfect for 20 minutes or more before the static shows up.  I checked the tubes in the amp and they test good.  Is there a component that heats up over time and becomes out of spec?  Would you pull the amp and tuner and look for high temps with an infared temp gun?  Any thoughts on where to focus attention or have any advice?

Harbourmaster

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Re: Magnavox AMP 175-77
« Reply #1 on: January 25, 2017, 02:09:04 PM »
Time to start checking and replacing out of spec resistors!
-- Aloha, Ken

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tdoades26

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Re: Magnavox AMP 175-77
« Reply #2 on: January 25, 2017, 02:57:19 PM »
But there are so many... :P

Larry H

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Re: Magnavox AMP 175-77
« Reply #3 on: January 25, 2017, 04:22:53 PM »
I had significant static in my Magnavox Serenade when I turned about a year ago, and it was a bad 12AT7 tube in the tuner.  Disconnect the RCA cable from the tuner to the amp and see if you still have the static.  If you still have the static, it is in the AMP 175.  If you don't, it is in the tuner.
--Larry

AlexanderMartin

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Re: Magnavox AMP 175-77
« Reply #4 on: January 26, 2017, 06:59:34 PM »
I have had issues with tube sockets doing that on all my units, tap on the tubes on both your tuner and amp. If they make a popping and stop the crackling, spray the socket with DeOxit.

tdoades26

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Re: Magnavox AMP 175-77
« Reply #5 on: January 27, 2017, 08:17:24 PM »
Thanks guys

I am going to try and find some time to give it some attention this weekend.

electra225

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Re: Magnavox AMP 175-77
« Reply #6 on: February 01, 2017, 10:01:29 PM »
If the function switch is dirty, it could cause the problem you describe.
If it ain't broke, call me.  I can break it....

tdoades26

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Re: Magnavox AMP 175-77
« Reply #7 on: February 03, 2017, 01:20:50 PM »
Thanks....I assume you mean the function switch for tuner, stereo, tape etc and not the speaker selector switch.
 

electra225

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Re: Magnavox AMP 175-77
« Reply #8 on: February 03, 2017, 07:55:32 PM »
Yessir, that's the one.  Clean it very well with De-Oxit or similar.  Good luck.
If it ain't broke, call me.  I can break it....