Hi Jon, I'm not familiar with the Ten-Tec Titan amp, but try disconnecting pin 8 from pin 7.
Pin 8 is the cathode connection for the protection diode in the SDR's ULN2003 driver chip (and actually pin 8 is a common-connection for the cathodes of *all* the protection diodes in the ULN2003). It's really only useful if you are using an external relay and have access to the relay's power, in which case you'd connect pin 8 to the relay's power (e.g. 12 v) so that the diode would be, in effect, in parallel with the relay coil and thus act as a snubber for the coil's voltage spikes. OK...I just downloaded the Titan schematic, and it doesn't look as though you are directly connecting to a relay within the unit, but rather it seems you're connecting to a transistorized keying circuit. So you don't need to worry about protecting the ULN2003A's driver from inductive kickback. The ULN2003A's open-collector driver should work just fine just as it is. Let me know how it goes! - Jeff, K6JCA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of K6JEK Sent: Tuesday, October 03, 2006 9:29 PM To: Flexradio Subject: [Flexradio] Amp won't unkey The Flex works fine with a Ten-Tec Titan but on a different amp it keys the amp but doesn't unkey. If I disconnect the keyline from the amp and plug it back in or power cycle the amp it unkeys. The Ten-Tec has transistor keying. This second amp has a 12V relay drawing 28 mA, keyed by grounding the the relay. Ought to be simple, shouldn't it? I used 7 for relay, 15 for ground and connected 8 to 7. Have any of you experienced this and fixed it? I saw similar items in the archives couldn't track down and actual fix. Thanks, Jon _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
