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 Meter....low 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, now....under full load (about 15> Amps) it drops to 12.1 volts...a drop of
1.70 volts....which 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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