RE: [Elecraft] OT power supply question
John - I have known some supplies to do this with the initial current inrush. A problem reported by some is singing of the transformer, usually due to loose laminations or transformer not tightened to case. I have never been fond of the Pyramid power supplies. My experience is that Pyramid achieved lower retail costs than Astron and other suppliers by cutting corners with the heat sink size (thermal mass) and filter capacitor ratings. The eHam.net product reviews appear to support my observations and experience http://www.eham.net/reviews/detail/974 http://www.eham.net/reviews/detail/960 As Dave Metz points out (and the reviews) some these short comings can be addressed by replacing key components with better values and ratings. http://www.seits.org/features/pwrsup.htm w9gb Message: 3 Date: Thu, 16 Dec 2004 17:31:49 GMT From: WT5Y Subject: [Elecraft] OT power supply question To: Elecraft mailing list I use a Pyramid power supply. PS35G to be exact. Sometimes when I turn it on it makes a thudding sound. But it works fine and it doesn't do it all the time. I am not the original owner and I've had it for a couple years so I know its getting pretty old by now. Wondering what would make that noise. Kinda sounds like someone hit a metal box with a mallet best I can describe it. WT5Y ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] OT power supply question
My Astron does it also, I suspected it was the capacitors, now thanks to you guys I know for sure. Now, can someone tell me why I make the same noise when my wife wakes me up at 5 am to get me off to work??? Happy Holidays to all, Tom WB2QDG K2 1103 - Original Message - From: [EMAIL PROTECTED] [EMAIL PROTECTED] Date: Thursday, December 16, 2004 12:31 pm Subject: [Elecraft] OT power supply question I use a Pyramid power supply. PS35G to be exact. Sometimes when I turn it on it makes a thudding sound. But it works fine and it doesnt do it all the time. I am not the original owner and Ive had it for a couple years so I know its getting pretty old by now. Wondering what would make that noise. Kinda sounds like someone hit a metal box with a mallet best I can describe it. WT5Y ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] OT power supply question
Probably inrush current charging the capacitor(s), I have heard it in other supplies (astron). You could shock mount the transformer maybe if it bothers you too much! 73/72 - Mike WA8BXN ---Original Message--- I use a Pyramid power supply. PS35G to be exact. Sometimes when I turn it on it makes a thudding sound. WT5Y ___ ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] OT power supply question
That 'thudding' is the transformer going Ugh during the first half-cycle (or full-cycle) of AC which it's trying to charge the completely DIScharged electrolytic in the supply. My Astrons all do that was well. 73, Tom N0SS At 11:31 AM 12/16/04, you wrote: I use a Pyramid power supply. PS35G to be exact. Sometimes when I turn it on it makes a thudding sound. But it works fine and it doesnt do it all the time. I am not the original owner and Ive had it for a couple years so I know its getting pretty old by now. Wondering what would make that noise. Kinda sounds like someone hit a metal box with a mallet best I can describe it. WT5Y ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
