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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Aug Thu 26, 2021 5:54 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 326
Location: angeles city.philippines,2009
yes it is for its age. that said there is no comparison with a cheap transistor am/fm nowadays. a crumby fm puts it to shame but i think that for the level of technology of the era they do really well.


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Wed 22, 2021 1:26 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 326
Location: angeles city.philippines,2009
so how did the set turn out?


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Wed 22, 2021 1:31 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 10768
Location: Beaver Falls, PA. USA
It's finished, and has been delivered. The radio turned out very well! I'm already on the next repair; a radio from a 1957 Chrysler.

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Tim KA3JRT


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Wed 22, 2021 4:56 pm 
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Joined: May Wed 20, 2020 1:33 am
Posts: 400
Location: Rockford, IL
I second fonebone on this one: that C53 is trouble and I have it clipped off but putting it back is on my list of projects next time I touch the radio (SX-43). I replaced all but three resistors and caps on it. The location of some of the parts is nothing short of ninja surgery to get to and replace.

If you solve the FM drift thing with this set please let us know - the FM drift of the SX-43 has been talked nearly to death with no solution other than "move the dial a little and chase the station".



fonebone wrote:
you would be well advised to replace c53 thats on pin 6 of the 7f8 tube. it will give trouble in fm and has been mentioned here. it drove me nuts finding it. if you opt to replace it cut the lead NEXT TO THE CAP BODY,as it will be easiest to solder with an elongated soldering tip using the stub to accept the new caps coiled end. to get at the other end pull the main dial and the front panel. theres a cover that provides bearing support and closes off the housing that holds the band switch, theres a terminal board that mounts the c53's other end. initially i just cut it and the radio played as normal. it ate at me and i eventually replaced it. ive read that SOME 7f8's require that cap while others dont, its lost to history now i think. and you are quite right about the resistors. also the selectivity switch should be looked at theres B+ on on switch terminal that carries to the center wiper. unfortunately theres a rivet that mounts a GROUND on the other side thats not more than a 32nd of an inch away its easy for it to carbon track and start burning up the center element . i had to mine mine out and fill it with epoxy. before it goes dead short it will burn up the resistor that goes to the wirewound 's' meter adjustment. but before it does that it fries the "s" meter.. just what happened in mine which plays nicely now.


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Thu 23, 2021 5:00 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 326
Location: angeles city.philippines,2009
HEY MR STRAT! long time no write. i cured most of the drift by removing the trimmer that sets the hi end. this is the first one on the tuning gang towards the front. at first i replaced it with a mica trimmer. i wasnt happy. i even got one of those cheap chinese LC meters. they do really work for checking a parts value. it was amazing how heating the trimmer removed revealed how a hair dryer could alter capacitance. i dug out the oem range trimmer its a different style it is ceramic with a silver plated brass half-moon disc. i deoxited the hell out of it and then scrubbed it with lacquer thinner on all sides. and re-installed it and re-aligned the fm. drift NOW is 1/2 a megacycle and goes away in an hour. it was almost 3 megacycles beforehand. i know it must sound like some sort of witchcraft. but ceramic is porous and silver oxide between the ceramic MUST effect capacitance. i commented about it but as per usual got no feedback, try it, it costs nothing but your time and materials which you probably already have


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Thu 30, 2021 3:35 am 
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Joined: May Wed 20, 2020 1:33 am
Posts: 400
Location: Rockford, IL
Mr Fone! Nice to hear from you :-)

What is the value of the trimmer you used? I have a bunch of them and that would be a nice fix. Do you have pix???



fonebone wrote:
HEY MR STRAT! long time no write. i cured most of the drift by removing the trimmer that sets the hi end. this is the first one on the tuning gang towards the front. at first i replaced it with a mica trimmer. i wasnt happy. i even got one of those cheap chinese LC meters. they do really work for checking a parts value. it was amazing how heating the trimmer removed revealed how a hair dryer could alter capacitance. i dug out the oem range trimmer its a different style it is ceramic with a silver plated brass half-moon disc. i deoxited the hell out of it and then scrubbed it with lacquer thinner on all sides. and re-installed it and re-aligned the fm. drift NOW is 1/2 a megacycle and goes away in an hour. it was almost 3 megacycles beforehand. i know it must sound like some sort of witchcraft. but ceramic is porous and silver oxide between the ceramic MUST effect capacitance. i commented about it but as per usual got no feedback, try it, it costs nothing but your time and materials which you probably already have


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 Post subject: Re: Hallicrafters SX-43 restoration
PostPosted: Sep Thu 30, 2021 10:13 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 326
Location: angeles city.philippines,2009
i dont recall as it was some time ago, but if you read carefully you will note i ended up putting the original back in after soaking in d100 for a few days.as they cant be taken apart i repeatedly cycled the thing and watched blackened d100 ooze out from between the ceramic and the contact trying to scrub it off through friction. i did this until nothing would change the red of the d100. then i scrubbed the entire cap with lacquer thinner using a stainless steel scratch brush (looks like tooth brush). i rinsed it in thinner let it dry and reinstalled it. and as i was out of ideas and just guessing,no one was more surprised than me with the results. normally those arent found topside at least from what i have experienced. it also gets much warmer there than underneath in the chassis, so combine the heat and contamination from being directly under the perforated "hood" so to speak seems to suggest this theory might have some merit. how much does your drift from cold? mine was damn near 3 mhz now down to 1/2 mhz. if yours improves at least i might be on the right track


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