I picked up this 1972 Magnavox stereo pedestal with AM/FM radio and 8 track deck yesterday. It also has a phono input so I thought I'd just plug in my modern Audio-Technica LP60 turntable and away I'd go. Except... nothing. I assume that means the receiver needs some work, but I'm not sure where to start. Replace all the capacitors? Clean the phono inputs with rubbing alcohol? I'm totally new to stereo systems, but I'm willing to do the work. Anyone have some pointers or advice on what to do first? I've tried the Audio-Technica on the 'Phono' and 'Line' settings.
Thanks for any help!
Thanks for any help!
I'd go with cleaning connectors and selector switch first, something like deoxit. Look inside (unplugged of course), and check any fuses are intact (and the correct value).
Test the phone input without connecting a cartridge is perhaps safer - touching a finger to a phono input should give a healthy loud burst of mains hum (turn down the volume first) -
without any risk of driving DC into your cartridge (usually there is a capacitor in the path though, but of course it could be failed).
There are no doubt dodgy caps in the unit by now, though presumably the receiver and amps are basically working. Some general checking of all the voltage rails, power consumption etc is worth doing (if you are happy working on a powered-up chassis). Visual inspection may turn up leaky caps anyway. There may also be layers of dust/grime to remove.
Quite a beast isn't it!
Test the phone input without connecting a cartridge is perhaps safer - touching a finger to a phono input should give a healthy loud burst of mains hum (turn down the volume first) -
without any risk of driving DC into your cartridge (usually there is a capacitor in the path though, but of course it could be failed).
There are no doubt dodgy caps in the unit by now, though presumably the receiver and amps are basically working. Some general checking of all the voltage rails, power consumption etc is worth doing (if you are happy working on a powered-up chassis). Visual inspection may turn up leaky caps anyway. There may also be layers of dust/grime to remove.
Quite a beast isn't it!
Does "nothing" mean that it really doesn't do anything at all in any of its modes - no radio, no phono, no indicator lights and so on? In that case it is likely to be some power supply problem. Or does everything work fine except the phono input?
That Magnavox requires a Ceramic Cartridge turntable (Micromatic/Collaro).
If the AT turntable has a built in preamp, it should work and provide sound.
Doubtful that the receiver has issues, they built them well, unless some putz was in the thing screwing around.
If the AT turntable has a built in preamp, it should work and provide sound.
Doubtful that the receiver has issues, they built them well, unless some putz was in the thing screwing around.
According to some Audio-Technica forums I've read, the AT does have a pre-amp, albeit a cheap one. I assume the Magnavox has never been maintenanced so I do anticipate some issues on that end.
There isn't a hum when you pass a finger over the phono inputs. I guess its time to disassemble on a bigger scale to check capacitors, connections, and fuses. My husband has dabbled in arcade and pinball repair so hopefully he can direct me on the voltage checks. Thanks for your response.
I see the problem there.
The "changer power" receptacle is a 3 pin connector.
The original changer controlled the power to the receiver, shutting it OFF when the changer was OFF - this of course was whenever the selector switch was set to "phono" only.
In order to "bypass" that condition, to keep the receiver powered up in "phono" position, internally the switch has to be re-wired - THIS IS A JOB FOR SOMEONE SKILLED WITH HOUSE CURRENT.
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