from ac to dc voltage drop

[1iwilly]

so my cobra 2000 gtl on the internal power supply shows 14.20 volts when the radio is keyed it only drops to 14.12
then when i switch to the external power supply set at 14.30 when the radio is keyed it drops to 13.52 volts but the volt on the power supply at the terminal doesn't drop they only drop inside the radio only drawing 2.3 amps so my question is why the 1-volt drop tr-41 was upgrade thinking the 3756 regulator

 

[Dmans]

DC power cord or DC power cord connections(including any inline fuse(s) in the DC power cord.

73
David

 

[1iwilly]

DC power cord or DC power cord connections(including any inline fuse(s) in the DC power cord.

73
David

yes 5 amp fuse on dc power cord

 

[Dmans]

the volt on the power supply at the terminal doesn't drop they only drop inside the radio

The problem is the only thing between your power supply and your radio such as:

DC power cord or DC power cord connections(including any inline fuse(s) in the DC power cord. (I should have written "Fuse connections" of the DC power cord.)
Dirty contacts of AC/DC switch on rear panel(if equipped)

73
David

 

[Captain Kilowatt]

Small size wire and longer lengths rob more power. Inline fuses really make a difference depending on the quality of the fuse holder. I had a 100 watt ham rig that would dim the panel lights with modulation until I beefed up the fuse holders.

 

[1iwilly]

heavy duty wire double fuse

 

[1iwilly]

here are what my reading look like off the external =14.34 at end of plug=14.34
connect the plug to radio at terminal =14.06 why the voltage drop i' tapping on the 2 pigtail terminal key up radio drops =13.39

 

[nomadradio]

Longer wires equals higher resistance. Higher resistance equals more voltage drop. The wires between the internal power supply and the radio are much, much shorter.

73

 

[Captain Kilowatt]

Just for shits and giggles measure the voltage drop across each fuse. Not the fuse itself but rather the wire immediately before the fuse itself. The contact relies on a simple pressure fitting and those were the type of fuse connectors that I had an issue with on my ham rig.

 

[1iwilly]

ok i found the problem something to me to check the dc plug adapter look at the pic it's the terminal is bad i took my 148 check the voltage and look no drop
i guess the previous owner never use it

 

[Captain Kilowatt]

That will do it. Those pins look rather crappy.