Since my C553 is hermetically sealed, rather than remove it, I inserted a current limiter. It's extremely simple, just a high-voltage depletion-mode MOSFET: the Microchip (nee Supertex) LND150. Drain towards positive, source+gate towards negative. If the cap ever lets go, the FET limits the current to Idss, i.e. 1 to 2 mA.
Dave Wise ________________________________ From: [email protected] <[email protected]> on behalf of Larry H <address removed> Sent: Sunday, May 5, 2024 4:40 AM To: R-390 Forum <[email protected]> Subject: [R-390] The R-390A Mechanical Fillter ‘killer’ cap C553 Hi all, I just updated my document (R-390 Newbie Support Info) on our website with a new paragraph at the end called: Replace the R-390A Mechanical Filter ‘killer’ cap C553. This is something that all folks new to the R-390A should know. Here's a link to the document: R390 Newbie Support Info <https://www.r-390a.net/R390%20Newbie%20Support%20Info.pdf> Regards, Larry ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
