Garey and Gary. Thank you for a very prompt and helpful answer plus the tip about leaving the switch on. Again I must say this site has been a great resource for me! John. GI3KDR
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell Sent: 31 July 2008 18:21 To: Drakelist Subject: Re: [Drakelist] TR7A 12v Switching John - Normally, the TR-7 switches both the AC supply to the PS-7 Power Supply - AND - the +12VDC to all of the transceiver with the exception of the PA stage. This was done to allow the transceiver to be used on either AC or DC if mobile use was desired. So if the external 12 VDC supply is ON, turning the transceiver on or off with the PWR OFF switch will turn off all but the PA. The AC part of the PWR OFF switch is connected to Pins 1&3 and Pin 2&4 of the PS7 Control connector (J5) on the TR-7. There was a mod circulating to remove the AC from the transceiver cabinet by putting a relay inside the PS-7 and using the relay to control the PS-7 AC primary. These switches do fail, and are essentially irreplaceable, due to being mounted on a dual control. I leave my PWR switches ON, and use an external power switch. I do this for all my older equipment that has control mounted power switches just because they are so difficult to source if they do fail. I wouldn't just plug in the PS-7 without doing some checking. You can check the continuity between Pins 1&3 and Pins 2&4 to see if the PWR OFF switch is still functional. If it is, then you are probably ok. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs <www.k4oah.com> John Stringer wrote: > I have been using my TR7A with a non Drake Power Supply. When I do this the > front panel on off switch switches the 12v. I always thought this strange as > it is supposed to switch the main supply to the PS7. Two questions: > 1. Is it normal that it switches 12v? > 2. Is it switching the full 23amps or just the receiver part if it is a > Drake arrangement rather than a modification? > Now I want to use a PS7 instead of the non Drake supply and this leads to > question3! > 3. Is it safe to plug in the PS7 and will the front panel switch turn on the > mains voltage? > John GI3KDR > > > > _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
