开云体育

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

=R= All Messages By This Member #30519 开云体育 Hi all, I’ve been silently following all the HT-37 xfmr discussion. I am the one who started the whole explosion of comments, tests, theories, etc. a couple of months ago. Ultimately I gave the fried transformer to Halden for analysis. I wrecked my HT-37 while trying to debug a problem with the T/R relay. What is problematic for the transformer is turning the radio from “on” to “standby” to “off“ and then immediately back to “on”.? The manual cautions against this. The designers obviously knew it was problematic. For a variety of reasons, I imagine, they chose not to fix it. Too costly, would take too much space for, say, a more robust transformer. Too much bother to engineer a 1950’s soft-start, or what have you. The transformers of many boatanchor transmitters are a weak link. It was probably one of the more costly single components, so vulnerable to cost-cutting. 73, =Randy= WB6MAI? =R= toggle quoted message Show quoted text From: [email protected] <[email protected]> on behalf of don Root via groups.io <drootofallevil@...> Sent: Saturday, July 13, 2024 5:36:33 PM To: [email protected] <[email protected]> Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Well Rick, ?????back a little you mentioned 300+ bucks for one but maybe that is a dream? How did you determine that switching ON? is what wrecks the switch, not switching OFF ??, I worry about contact bouncing on the ON stroke and acring when it is turned off , especially under load.? I guess I’m still wondering if it is a real toggle switch, or what.?? don ? From: [email protected] [mailto:[email protected]] On Behalf Of Rick W4XA Sent: Saturday, July 13, 2024 7:47 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? On Fri, Jul 12, 2024 at 03:48 PM, don Root wrote: Rick they have oodles of ?SRS. ??which exact one ??? maybe a link so we can see what you recommend??? … don ?? -- don??? va3drl Don, Are you asking which solid state relay I am putting in my Valiant? I only suggest using them in place of a "step-start" circuit since the only thing a step-start protects is the ON/OFF switch and only then during "Turn-On" especially if it's switch that is essentially irreplaceable, (like certain Drake, Collins, or other unique ON/OFF switches. It seems prudent to try to protect them. In the Drake AC-4 supply, I used an OPTO22 120A25 (120V @ 25A) controlled by AC. I found them on eBay, "pre-owned"........ if you have to get them from Mouser or Digikey etc (new) , You'll likely not want them. They cost way too much. In the Johnson Valiant, to replace the PTT plate transformer relay, I'll probably try an old used CRYDOM D1210 (120VAC 10A, controlled by 3-32VDC) since I have DC available for it. The Valiant plate supply transformer doesn't draw much current when keyed, probably somewhere around 3A . All the SSR's I have, I found on eBay, or scrounged from old equipment. One only needs to mind the maximum possible current draw during turn on. ? -- 73/Rick W4XA -- don??? va3drl

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#30519

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