I have an Amplifier Research 25A100 amplifier that developed a gain stability problem after 20+ years of use and several over-power incidents caused by several individuals including myself. Turns out that the carbon composition resistors used in the drain-to-gate feedback of the output stage had gotten tired of all the abuse. I replaced them with more stable metal oxide resistors and the problem went away.
Don Borowski EMC Compliance Engineer Schweitzer Engineering Labs Pullman, Washington, USA From: "Sundstrom, Michael" <[email protected]> To: John Woodgate <[email protected]>, "[email protected]" <[email protected]> Date: 08/10/2012 10:14 AM Subject: RE: [PSES] Ophir Amplifier 5127F for Rent? Sent by: [email protected] I'm betting on a broken connector....look at each connector with a magnifier! Michael Sundstrom OHD TREQ Dallas Electronic Lab Analyst EMC Lead (214) 579 6312 office (940) 390 3644 cell KB5UKT -----Original Message----- From: John Woodgate [mailto:[email protected]] Sent: Friday, August 10, 2012 11:57 AM To: [email protected] Subject: Re: [PSES] Ophir Amplifier 5127F for Rent? In message <c3e2eb4dcd575846a467e2b9d2bc36152aea4...@by2prd0410mb365.namprd04.prod.o utlook.com>, dated Fri, 10 Aug 2012, Elliott Mac-FME001 <[email protected]> writes: >The one we have now seems to have some sort of instability ? the field >strength in our chamber varies 3-5 V/m [in a 60 V/m range&] even >setting the system for a single frequency and constant power. Change the cables and clean all (that means ALL) the connectors. May not work, but if it does .... -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Instead of saying that the government is doing too little, too late or too much, too early, say they've got is exactly right, thus throwing them into total confusion. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
