OK, my new MAX1406's came in today. I really made a point to check out every possible cause for the previous chip issues.
Installed the new MAX1406 and now have 122.1 V's at the junction of C77 and R11. Also have a -22.4 V's at pin 8 of U4. So, the new chip fixed this issue............ Now to move on to the next challenge. Thanks to everybody for your suggestions and support. 73 Jerry N0JRN ----- Original Message ----- From: "Don Wilhelm" <d...@w3fpr.com> To: "n0jrn" <n0...@mchsi.com> Sent: Monday, December 14, 2009 6:22 AM Subject: Re: [Elecraft] KPA100 problem > Jerry, > > I will take back what I said about U4 - it is faulty. > That negative voltage is there only to allow the RS-232 drivers to produce > a negative level, the current draw should be minimal. > The only thing U4 does is convert RS-232 levels to TTL levels and > vice-versa. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html