[Elecraft] OT - Astron RS-20A Issue
Ladies and Gents I repaired an RS-20A recently. The balancing resistors from the pass transistors had burned up because someone put a 15 amp fuse on the primary side with a load more that 16 to 20 amp on the 13.8 volt side. Not ever done this before, I made sure the 723 was set at 13.8 volts and then used a 12 volt light as a load. She regulated quite well. But now, the regulation voltage has increase to 15.5 volts. This happened over a 24 hour period. This does not seem right to me...and I wonder what some of you thing about this. Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] OT - Astron RS-20A Issue
Lee Was the rise to 15.5 with or without a load? How much load were you using? 73 John WA8KNE ETC USN retired On 8/26/07, Lee Buller [EMAIL PROTECTED] wrote: Ladies and Gents I repaired an RS-20A recently. The balancing resistors from the pass transistors had burned up because someone put a 15 amp fuse on the primary side with a load more that 16 to 20 amp on the 13.8 volt side. Not ever done this before, I made sure the 723 was set at 13.8 volts and then used a 12 volt light as a load. She regulated quite well. But now, the regulation voltage has increase to 15.5 volts. This happened over a 24 hour period. This does not seem right to me...and I wonder what some of you thing about this. Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] OT - Astron RS-20A Issue Part II
I adjusted the regulator without a load to about 13.80 volts. Over the last 24 hour it rose to 15.5 volts or so. It seem to regulate. I ran my two meter SSB rig and a 100 Watt amp (15+ amp ICAS) last night without issue. I figure the regulation percentages at around 2%...but this morning it rose to 15.5 v with no load. Still regulates. I will take a look for components that might be a little flaky. Just doesn't make sense to me that a 723 would do this. Lee K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] OT - Astron RS-20A Issue - Part III
This is still a mystery, but I cannot set the voltage any lower than 14.5 volts. That is where the voltage adjust goes to minimum and can't go any lower. No fried components I can see. The TIP29 has been replaced at one time, but that is just driving the pass transistors. Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] OT - Astron RS-20A Issue - Part III
It seems that you are not getting the required voltage to the pass transistors to cause them to adjust enough. i.e. Too much drive voltage coming from the regulator. This means the control voltage from the regulator is still too high. That is where I would look. Robert VE3RPF Lee Buller wrote: This is still a mystery, but I cannot set the voltage any lower than 14.5 volts. That is where the voltage adjust goes to minimum and can't go any lower. No fried components I can see. The TIP29 has been replaced at one time, but that is just driving the pass transistors. Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
