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Title: SX-42 Help Post by: Edward Cain on December 30, 2009, 01:40:39 PM I want to take a look inside the transformer cans, especially the FM discriminator. It appears that the cans should lift off from the top side after removing one or two screws in the sides. Well, I've removed the screws and the cans won't budge.
Any help will be appreciated. Thanks, Ed Title: Re: SX-42 Help Post by: Edward Cain on December 30, 2009, 05:06:21 PM Oops! Those nuts on the underside of chassis also hold the cans. :-[
Title: Re: SX-42 Help Post by: W7SOE on December 31, 2009, 12:56:36 PM Ed,
I think those may have to be un-wired to remove. Rich Title: Re: SX-42 Help Post by: w3jn on December 31, 2009, 02:12:32 PM Nope, the tops pop right off.
Title: Re: SX-42 Help Post by: W7SOE on December 31, 2009, 02:25:38 PM Nope, the tops pop right off. Does that apply to the BFO coil? I am working on one right now and I have removed the two bottom nuts and the side screw and it still doesn't want to come off. Rich Title: Re: SX-42 Help Post by: W3RSW on December 31, 2009, 02:32:36 PM Hmmm, needs the Russian weighted repair apparatus ;D
Title: Re: SX-42 Help Post by: W7SOE on December 31, 2009, 03:03:00 PM Hmmm, needs the Russian weighted repair apparatus ;D ?????????? Title: Re: SX-42 Help Post by: w3jn on December 31, 2009, 03:59:30 PM Can't remember on the BFO coil. But I did have to remove every IF xformer cover and replace all the SM caps inside on the last SX-42 I did. You can certainly work on the guts of the IF xformers without removing them from the radio.
Title: Re: SX-42 Help Post by: Ralph W3GL on December 31, 2009, 04:18:09 PM Translation: 4.5 kilogram (10 lb) mall... Hmmm, needs the Russian weighted repair apparatus ;D ?????????? Title: Re: SX-42 Help Post by: W3RSW on January 01, 2010, 09:59:12 AM Exactly,
-And Happy New Year to all you hammers out there. 8) Title: Re: SX-42 Help Post by: N3DRB The Derb on January 01, 2010, 10:45:08 AM wifey Glo calls us hammers.... ::)
Title: Re: SX-42 Help Post by: Edward Cain on January 01, 2010, 02:40:36 PM JN,
Any tips to offer for replacing the original mica caps with modern package type? Placement, lead length etc? I notice in the FM discriminator their are two mica caps anchored in the metal frame at top and bottom respectively. Other cap and resistor are supported by their attachment to the anchored cap. Ed Title: Re: SX-42 Help Post by: w3jn on January 01, 2010, 02:56:10 PM I just clipped the old ones as close to their bodies as possible, then slobbered the new ones onto the stubs of the old ones.
As I recall I tried unslobbering the old ones but everything started coming apart - the coil windings came unsoldered, etc. It's just a lot easier and neater NOT to unsolder the old ones, just clip 'em out, and attach the new caps to the stubs. Title: Re: SX-42 Help Post by: KM1H on January 02, 2010, 11:26:44 AM Yep, sometimes its better to make a mess than cause damage, at least it will be will hidden.
Carl KM1H Title: Re: SX-42 Help Post by: WQ9E on January 04, 2010, 09:48:07 AM I use the same method as JN. You don't want to cause irreparable collateral damage trying to replace these caps.
I would add, check the insulating paper used on the inside of the "can" to prevent shorting because after 60 years or so it has likely deteriorated. Title: Re: SX-42 Help Post by: W7SOE on January 04, 2010, 12:02:10 PM I use the same method as JN. You don't want to cause irreparable collateral damage trying to replace these caps. I would add, check the insulating paper used on the inside of the "can" to prevent shorting because after 60 years or so it has likely deteriorated. That insulating material, by the way, was what was causing my can to stick. If you cannot remove the can after removing the two underside nuts I would recommend loosening the side screw and pushing or rapping sharply on the screw to separate the innards from the can. Rich |