[Elecraft] OT - Astron RS-20A - Part IV (me bad)

2007-08-26 Thread Lee Buller


One of those AH-HA moments.  I noticed the battery indicator had appeared on my 
Digital Multi Meterlow battery.   Think that would make a different 
measuring voltages?  Even this Liberal Arts Major understands that.  Replaced 
the battery and the PS could be set at 13.80 volts.  Low batt in the DMM caused 
the false readings.

But, nowunder full load (about 15 Amps) it drops to 12.1 volts...a drop of 
1.70 voltswhich means the voltage regulation percent is 14 %.  I don't know 
if that is bad or good.  I might have a Pass Transistor gone...it has two.  Any 
one venture and opinion?  On my RS-12A at 10 amps, I am dropping just .05 volts 
for a percentage of less that 1%

I think I need some 3055 or something like that.

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?
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Re: [Elecraft] OT - Astron RS-20A - Part IV (me bad)

2007-08-26 Thread Don Wilhelm

Lee,

The pass transistors *could* be to blame, but check all the connections 
both inside and outside the power supply before drawing a conclusion 
that the pass transistors are at fault.  At 15 amps it only takes 0.1 
ohm resistance  to drop 1.5 volts.  It is a good idea to re-tighten all 
the hardware in the PS.


73,
Don W3FPR

Lee Buller wrote:

One of those AH-HA moments.  I noticed the battery indicator had appeared on my 
Digital Multi Meterlow battery.   Think that would make a different 
measuring voltages?  Even this Liberal Arts Major understands that.  Replaced 
the battery and the PS could be set at 13.80 volts.  Low batt in the DMM caused 
the false readings.

But, nowunder full load (about 15 Amps) it drops to 12.1 volts...a drop of 
1.70 voltswhich means the voltage regulation percent is 14 %.  I don't know if 
that is bad or good.  I might have a Pass Transistor gone...it has two.  Any one 
venture and opinion?  On my RS-12A at 10 amps, I am dropping just .05 volts for a 
percentage of less that 1%

I think I need some 3055 or something like that.

  

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