Thanks for all the replies on this. Larry, thanks for making the measurements on yours. That confirms that mine has apparently been fried, as it measures about 25 ohms keyed or not, and I do have the X2 sequencing checked in setup. I suspect RF must have gotten into my isolation box, as I was not connected directly to the Henry key jack from the SDR. Initially I had a boat load of RF in the shack until I found the problem. By then it was too late, and it quit keying.
Oh well, in the meantime I will operate with a switch. Anyone know what I need to do to make the repair to the ULN2003A circuit? Thanks again for the help! Brian On 5/19/06, Larry Taft <[EMAIL PROTECTED]> wrote: > Brian, > > I just made some measurements on my SDR-1000 with the power OFF. > X2-pin7, reads infinite resistance using a digital multimeter. In the > Diode test position with plus to pin 7 and minus to ground it shows open > circuit. With the leads reversed minus to pin 7 the reading is 540 > millivolts. This is consistent with the ULN2003A circuit which has a > transistor open collector from pin 7 and the emitter to ground. Also > a diode cathode pin 7 with anode to ground. You should get the same > readings measuring pins 1 through 6 to ground as these are all the same > kind of circuit. > > Unfortunately pins 1 through 6 don't have the external amplifier > sequencing delay so tring to use one of these will result in "hot > switching" the amp relay. For now I'd use a foot switch on the amp to > turn it on just before you PTT the SDR. One man band sort of thing but > it will work as I have done it here with my Drake L-4 before I got the > FET isolated keying module from N0XAS. I put a back diode in my L-4 as > I use it with several other radios. > > I also looked in the manual for my Henry 2K and it shows there is NO > back diode for the changeover relay. There aren't any voltage values > for the relay so I'm guessing its a 24 volt coil that draws 50 mills or > so when operated. Measure the open circuit voltage of the Henry at the > RCA jack and then use the milliamp meter to check the coil current. > When the relay keing circuit is opened to turn the relay off you can get > over 400 volt spike on the control line. This can cause failure of the > X2-7 transistor. > > Haven't run the Henry in years. Its gained way too much weight just > sitting in my office. > > 73, Larry K2LT > > Brian Sherrod wrote: > > I just hooked up my SDR to my Henry 3K Classic. I used pin 7 and pin > > 15 (grnd) on the X2 connector to cause the relay to go to ground, > > however something is wrong. If I use my ohmmeter between 7 and 15 > > without being keyed, I am seeing about 40 ohms, and when I key the > > SDR, it does not change. > > > > I can transmit on the Henry, but the ant relay does not switch back so > > that I can receive without pressing the standby switch on the amp. > > > > The amp only requires grounding the center pin on the rca jack, which > > is what I thought a connection of pin 7 & 15 would do on keyup of the > > SDR. > > > > Any suggestions appreciated. > > > > Brian / w5ami > > _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
