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 Help with ASTOR radiogram
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 Return to top of page · Post #: 16 · Written at 10:55:33 AM on 6 June 2016.
Scotty's Gravatar
 Location: Melbourne, VIC
 Member since 26 December 2010
 Member #: 794
 Postcount: 387

Thanks guys. As mentioned at the start, the amp works fine so the phono side is going great, the radio just emits static - like you in the middle of nowhere - I just need to find the time to go through the damn thing again I guess


 
 Return to top of page · Post #: 17 · Written at 5:02:01 PM on 6 June 2016.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5465

Clearly the issue is in the RF section. The yanks have something called Deoxit it think, don't know if we have it here, but they seem to consider it the universal widget, for dirty switches like that. Check & see if it hasn't got Mouse urine on it. Different method needed for removal.

As said my first thing to use if I think it is the oscillator that has failed like that, is an oscilloscope. Then the voltages. If it is still not obvious its the Signal Generator & Oscilloscope, to see where the signal is being lost.


 
 Return to top of page · Post #: 18 · Written at 8:54:41 PM on 6 June 2016.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6799

 
 Return to top of page · Post #: 19 · Written at 9:05:12 PM on 7 June 2016.
Viccadillac's Gravatar
 Location: Perth, WA
 Member since 7 May 2012
 Member #: 1140
 Postcount: 157

Check the continuity of the IF coils.

If it has been used without being recapped chances are it has blown an IF coil , or open circuited one. I am having to repair a lot of these lately. Use your ohm meter and check . They are usually very low ohms . It will read high if open or not at all.

Cheers


 
 Return to top of page · Post #: 20 · Written at 12:22:34 AM on 8 June 2016.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5465

This is rather why I run an IF signal through. A dead giveaway for an open IF primary (rarely seen here) is no plate volts. I have a Grigsby-Grunnow here and both IF coils are bobbins, both have open primaries.

This can happen with top trimmers if you short the primaries trimmer to ground, by using a metal screwdriver.

Marc


 
 Return to top of page · Post #: 21 · Written at 4:53:01 PM on 16 June 2016.
Scotty's Gravatar
 Location: Melbourne, VIC
 Member since 26 December 2010
 Member #: 794
 Postcount: 387

Thanks Guys, I have brought the thing back to the workshop and intend on checking it further in the next week.


 
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