Curt, Thanks for sharing the useful info.? As to the heat, when I rebuild the supplies, I always offer people a non-destructive fan upgrade to prolong component life.
73, Evan -----Original Message----- From: Curt Nixon <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Sent: Wed, 16 Apr 2008 8:44 am Subject: Re: [drakelist] L-4PS hum Curt Nixon <[EMAIL PROTECTED]> made an utterance to the drakelist gang? ----------------------------------------------------------------------? Hi Evan:? ? On the transformer buzz...the bolts are a way--sometimes they get loose. Rather than the rtv tho..I guess I would look for an industrial motor repair shop that rewinds big motors--they will more than likely have a vacuum varnish tank for impregnating windings. They would probably dip your transformer in the tank for next nothing (perhaps a box of danish for the crew!).? ? THe varnish will secure any loose windings AND lamination voids that can make noise. Place shrink tubing over the leads and shrink it. you can cut it off afterwards so the leads are not too stiff.? ? I've also seen the case vibration resonance mentioned and the rubber wedge can fix it if that is the problem--if it is, you can tell by placing yopur hand on the case to kill the vibe. DOn't obstruct airflow with large foam pieces tho.? ? FWIW? ? Curt? ? KU8L? ? ? [EMAIL PROTECTED] wrote:? > [EMAIL PROTECTED] made an utterance to the drakelist gang > > ----------------------------------------------------------------------? > Joe,? >? > I've rebuilt an number of L4B supplies and have found in several cases of > > hum, it was caused by a mechanical "resonence" if you will between the outer > case > and the transformer core. Reshaping the case or putting stiff foam > rubber > between the case and core can help. While I've not done this on an > L4PS, I have > cured hum on some other transformers by flowing flowable RTV > onto the > windings, from above, let it cure, then from below. Sometimes it > works, sometimes > not, but only if a winding is loose. The flowable RTV is > sold as windshield > sealant for cars and is flowable where standard RTV is > not. If a lamination is > loose, then tightening the bolts might help.? >? > 73,? >? > Evan? >? >? > **************? > It's Tax Time! Get tips, forms and advice on AOL Money & > Finance.? > (http://money.aol.com/tax?NCID=aolcmp00300000002850)? > ---------------------------------------------------------------------- > > Submissions: [EMAIL PROTECTED] Unsubscribe: > [EMAIL PROTECTED] - unsubscribe > drakelist in body Hopelessly > Lost: [EMAIL PROTECTED] - help in body of > message Zerobeat Web > Page: www.zerobeat.net - sponsored by www.tlchost.net > > ---------------------------------------------------------------------- ? ----------------------------------------------------------------------? Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body? Hopelessly Lost: [EMAIL PROTECTED] - help in body of message? Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net? ----------------------------------------------------------------------?
