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Power supplies and amperage draw AT-6666 -> KL503

Discussion in 'General CB Services Discussion' started by TheRATT, Jan 11, 2019.

  1. TheRATT

    TheRATT KJ7GKX

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    Hello,

    Trying to figure something out. I have a PowerMax 50 amp switching power supply.

    I have my AT-6666 (rated 12A) and a KL503 (Rated 30A) that it runs.

    My symptoms are that the 503 just shuts off after 10 minutes of SSB chat. The 503 isn't even warm, much less hot.

    So is my 50A not enough to drive these both and the amp is shutting down due to power starving?



    I'm pretty sure this is a power supply thing, your input is appreciated.

    213
     

  2. sp5it

    sp5it Master of puppets

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    KL503 can't just switch off by itself.
    Mike
     
  3. TheRATT

    TheRATT KJ7GKX

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    OH yes, all the lights go out and it is non-functional.

    After 2 or 3 minutes it comes back on.
     
  4. sp5it

    sp5it Master of puppets

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    According to schematic there is no circuit can behave like that.
    Maybe someone modded it with thermal breaker. That would explain why it goes off after some use than comes back to life.
    Mike
     
  5. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    You have some bad solder joints in the amplifier. The KL-503 has some very cheap switches installed. If you try to resolder them they will quit working.
     
    Shadetree Mechanic likes this.
  6. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    I 2nd the notion - looks like you'll need to pop the hood and extract the board to inverse-tigate. :(

    There may be more than one reason and it may be related to the switching circuit used to toggle those relays.

    If you use "sense" and put too much power into it - well, you cook the transistor and it will quit, and eventually fail - the "Sense" circuit does not take too kindly to hi drive radios - so something is afoot with the 503 that usually a 203 deals with every day...

    For you to say it's cool to the touch scares me even more - in my use of amps if it's not warm in 1 minute I'm not driving something right. IF something is not bolted down to transfer heat away - it may shut down and force a power down - so again, look under the hood and see if there is something afoot - or a hand - or even a errant nut left behind from a squirrel.
     
  7. 9C1Driver

    9C1Driver Sr. Member

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    If the amp shuts down and the radio is still on and transmitting then the power supply is fine. I assume you are running both off the same 50 amp supply. Your in line external watt meter can confirm this. Sounds like your amp is messed up, the kl503 has no kind of auto shut down feature.
     
    sp5it likes this.
  8. TheRATT

    TheRATT KJ7GKX

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    Now this is the most understandable explanation to my symptoms I’ve heard. I’ll know tomorrow when I get a second 75-amp (MFJ) power supply.

    I’ll report back if it solves the problem. If it does not, I’ll be replacing the 503 and diving into the broke one.
     
  9. TheRATT

    TheRATT KJ7GKX

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    OK, so, I got a new power supply (75 amp) just for the 503.

    I left the Anytone on the 50 amp - everything is clicking really well now!
     
  10. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    The amp will act up again.. give it time. you might need a third power supply :whistle:
     
  11. TheRATT

    TheRATT KJ7GKX

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    I will definitely let you know if that happens but after a weekend of clicking it is going strong still. I'm only running on 1st setting with the drive about 10W sideband.
     
  12. tba02

    tba02 WOOF

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    Some notes of mine from 2015.
    Optima @ 10 PEP SSB | 3.8 amps | Dummy Load | Power Supply at 13.8v
    MFJ-826B Meter, Megawatt 36s P/S

    KL-503
    Variable | Amperage Draw| Output
    Setting 6 | 32.5 amps | 200 watts
    Setting 5 | 30.6 amps | 192 watts
    Setting 4 | 30 amps | 185 watts
    Setting 3 | 28 amps | 160 watts
    Setting 2 | 26.5 amps | 149 watts
    Setting 1 | 18 amps | 70 watts
     
    TheRATT likes this.
  13. TheRATT

    TheRATT KJ7GKX

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    So, after adding its own 75 amp power supply, the amp has been very happy, no hiccups. I have added a nice fan to the top. That's the rest of the story!
     
  14. jkp1

    jkp1 Member

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    So why bother with the amp if your only getting 70w out of it? Won't the Anyone due about that barefoot?.
     
  15. Dmans

    Dmans Sr. Member

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    2 different operators, 2 different driver radios, 2 different situations........

    73's
    David
     

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