Pete, The very old SDR-1000 units have OPA2677 as the final amplifier and cannot stand short circuit. The newer radios use OPA2674 that has internal short circuit protection. Anyhow, ask Flex people directly, they know better the difficulties with some of the first production units.
73, Ahti OH2RZ On 09/12/2008, Pete Ferrand <[EMAIL PROTECTED]> wrote: > > Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it > to a linear. Wasn't happy about that but since I accidentally hooked up the > attenuator resistors wrong I wasn't too surprised since the rig saw a very > high impedance. Worked fine ever since. > > Unfortunately I'm less happy about blowing the amp this morning, about a > half year after that first incident, whilst trying it on six meters for the > first time. Without the linear which doesn't cover six. Just wanted to see > if I could work a couple locals. As far as the MFJ-269 showed there was a > perfect match into the ATU but when I increased the power beyond about a > tenth of a watt output the opamp popped again. > > Besides the time and money aspect, the circuit board clearly can't take a > lot of parts replacements. > > Has anyone figured out how better to protect this part? Or some better > solution. This is a four stack including the rfe board, older version with > nylon spacers. > > Thanks. > > -Pete > WB2QLL > Somers, WI > > > > > _______________________________________________ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: > http://www.flex-radio.com/ > _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
