| Author |
Message |
    
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 11
Registered: 5-2011
| | Posted on Wednesday, June 15, 2011 - 5:44 pm: | 
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Have a s-3 175 that is not swinging power, it dead keys 1 watt and will only do 2 or 3 watts, the swr will not cal on the meter either, the warranty has just exp. got it from coppers a little over a year ago, what could be the problem |
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 12
Registered: 5-2011
| | Posted on Thursday, June 16, 2011 - 5:23 pm: |
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well now i keyed it up and it kick the protection on on my power supply, i unhooked it and even with the radio off it still does it, does anyone have a idea |
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 13
Registered: 5-2011
| | Posted on Thursday, June 16, 2011 - 8:25 pm: |
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ok here is were its gets strange, trying to find out were the short was i decided to cut the main power wire to the rfx 175 when i did so the radio powerd up fine, i keyed the mic and it deadkeyed 15 watts and swing 100, how could it do this with the power dead to the cabinet. I asked for a radio check and got one that said lound and clear, help me out here if u can. |
Jon666
Intermediate Member
Username: Jon666
Post Number: 413
Registered: 11-2003
| | Posted on Friday, June 17, 2011 - 7:14 am: |
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what size power supply are you using. |
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 14
Registered: 5-2011
| | Posted on Friday, June 17, 2011 - 8:25 pm: |
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its a ps21k 18amp. it is a 450 watt output. |
Funtimebob
Intermediate Member
Username: Funtimebob
Post Number: 278
Registered: 5-2002
| | Posted on Saturday, June 18, 2011 - 12:28 am: |
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Nope, not if its 18 amps continuous @13.8v
P=IxE (Power in watts equals voltage times the current)
13.8volts x 18amps = 248.4watts (Continuous duty)
13.8volts x 20amps = 276 watts intermittent.
to put out 450 watts at 13.8 volts the supply would need to produce 32.6 Amps of current.
The 450 watts is what the supply is consuming in order to produce it's rated output power and gives you an estimate of it's efficiency.
276w/450w = 61.33% efficiency.
even though I'm not an engineer
(only had 3 quarters to go when I had to drop out because of the wife's dialysis etc)
I did spend the night at a Holiday Inn 
73 De Bubba
Honorary O.F.
D.O.M. Club (Junior Auxiliary)
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Funtimebob
Intermediate Member
Username: Funtimebob
Post Number: 279
Registered: 5-2002
| | Posted on Saturday, June 18, 2011 - 12:43 am: |
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PS
I don't understand how that radio supposedly uses 7 amps max according to a quick web search.(that's only 96.6 watts of power for 175 watts out?) when my "Rig" at 100 watts output lists a requirement of 22 amps (300+ watts).
Something fishy there....
73 De Bubba
Honorary O.F.
D.O.M. Club (Junior Auxiliary)
|
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 15
Registered: 5-2011
| | Posted on Saturday, June 18, 2011 - 12:00 pm: |
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I guess u are right but i remeber reading somewere it was 450 watt output, i may be confused, i have read alot about power supplys lately, but anyway it should be enough to power the s-3 shouldnt it, the radio started it promblems in my buddys peterbilt after a year and 2 month of trouble free service. |
Funtimebob
Intermediate Member
Username: Funtimebob
Post Number: 281
Registered: 5-2002
| | Posted on Saturday, June 18, 2011 - 3:36 pm: |
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If that radio really puts out 175 watts I don't see how that power supply could handle the radio.
You would need close to 40 amps peak on transmit and not the 7 amps I read in an advertisement.
Since receive doesn't take a lot of current the supply probably can at least handle that.
73 De Bubba
Honorary O.F.
D.O.M. Club (Junior Auxiliary)
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Jon666
Intermediate Member
Username: Jon666
Post Number: 414
Registered: 11-2003
| | Posted on Saturday, June 18, 2011 - 6:43 pm: |
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i dont see how cutting the wire to the rfx 175
would make it work. but anyhow you ned a bigger power supply. i know my galaxy 95t draws more than 18 amps |
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 16
Registered: 5-2011
| | Posted on Saturday, June 18, 2011 - 8:25 pm: |
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I have seen the radio do 150 watt in my buddys truck, but the power supply is not the problem here, it started acting up in the truck, frist it would dead key 1 watt, and swing 2 to 3 watts, then it kicked in the protection on my power supply, it didn't matter is the power was on the radio it would still kick the supply, but after cutting the wire to the kicker it started working, 15 watts to 100watts easy, what could be bad in the amp to cause this because it must be were the problem is, then to make things worse another buddy gave me his stock s-3 that he was told it needed finals put in, it would only light up no tx or rx, when i opened it up the final near the driver was in pieces, now he had had a driver put in and how the tech missed that i don't know but after putting in the finals it would rx but will not key a thing what about this radio anybody got any ideas on it and thanks alot for the info jon666 i like any info i get i am new to the hobby and enjoy it very much, I used to cobra and related radios but the 10 meters are quit a bit different |
Fieldrat
Junior Member
Username: Fieldrat
Post Number: 24
Registered: 5-2011
| | Posted on Wednesday, July 13, 2011 - 9:42 pm: |
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Ok guys radios are fixed, here what i found, the field coils on the 175 cabinet were the wire raps around them in one of the wraps on the inside the insulation on the wire was worn threw. now the other had the big capasitor blow, must have happen when the finals blowed, there up and working fine. Maybe this will help someone eles. |
