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 Post subject: If transformer (Silver Mica ?) - 56 Nash Metropolitan AM
PostPosted: Sep Fri 10, 2021 4:54 pm 
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Joined: Sep Thu 09, 2021 3:02 pm
Posts: 1
Greetings All....

From reading some past posts on the subject, I'm starting to wonder why I chose the AM radio out of my 56 Met as my first restoration/repair project...
But I've started now, and I told myself I would not give up until it's working !

Here is my question: I have attached a pic of IF Trans. #1... I'm assuming #2 looks exactly the same.... I have read up on the SMD issue, but my IF doesn't seem to look like all those others that were cursed with SMD.... It has the two iron cores, but I don't see where or how the unit would move across a mica sheet... The coils measure appx. 25.5 and 26 ohms, as per the schematic... I measured for capacitance, which should be 100 pF on each coil, and I am reading appx. 170 pF .... Can anyone tell me if these IF's do utilize the silver mica sheets ? If not, where do the 100 pF capacitors hide ?
Would the extra 70 pF have a big operational impact ?

Thanks to all, any assistance would be greatly appreciated...

Rick


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 Post subject: Re: If transformer (Silver Mica ?) - 56 Nash Metropolitan AM
PostPosted: Sep Fri 10, 2021 8:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2459
Location: Lafayette, CO
If l were you, l would find out the IF frequency and run a signal generator 'hum' through the front end. Put that coil back first of course. Can you post a schematic? Pulling an IF coil is not generally done without reason. And noise can come from anywhere. If the vibrator is working well, one can hear it in the speaker. Craig


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 Post subject: Re: If transformer (Silver Mica ?) - 56 Nash Metropolitan AM
PostPosted: Sep Fri 10, 2021 8:50 pm 
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Joined: Feb Sat 06, 2016 1:47 am
Posts: 3623
Location: La Mesa Califonia
The mica sheets are in the base of the IF coils. To read the values remove one wire from terminal lug. Read across the two lugs. Don't worry about SMD until you put it all back together and test play the radio.


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 Post subject: Re: If transformer (Silver Mica ?) - 56 Nash Metropolitan AM
PostPosted: Sep Tue 14, 2021 2:15 am 
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Joined: Dec Sat 24, 2011 9:17 pm
Posts: 8350
Location: Vancouver Island, Canada
Nash Metropolitan - the only American auto maker to choose a British four-banger for their power plant.
But they are a novelty vehicle and loads of fun, I'm sure. 8)

T-bird is right, you might have had ok results just with a cleaning and recap, new capacitors.
I believe silver mica migration occurs when the radio is under power, not so much when a car sits idle for most of its life.
Make sure the buffer cap across the vibrator output is rated for high voltage and close to spec.
Keep us posted with your progress.

_________________
Watch the doughnut, not the hole.
Burl Ives, RIP, oldtimer.
[:l>)


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