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L4810 volt reg X-Ref

Discussion in 'General Electronics' started by sdh, Nov 22, 2003.

  1. sdh

    sdh Guest

    Hi,

    I have a BP200 battery pack for an Bearcat XLT200 scanner. I had
    replaced the nicads with NiMH, and I think I rushed the charge a bit.
    Now, out of the regulator I get 9.6 volts, but no availble power to
    speak of. I'm pretty sure that the L4810CV voltage regulator is toast.
    This part is made by SGS-Thompson I belive. I had sent e-mail to Uniden,
    asking if I could get the part, and they didn't even mentions the part
    in thier reply, only to call sales and oder a new BP200 battery pack.

    I'm sure there is a replacement part that can be had or to be made to work.


    Any help is appriciated!!!


    Steve
     
  2. Robert Baer

    Robert Baer Guest

    We are in the "toss and buy new" economy now...
    However, if you are sufficently knowledgeable inelectronics, then call
    a distributor for 2 or 3 samples and DIY.
     
  3. sdh

    sdh Guest

    Robert,

    Thats the problem. Mouser has the exact replacement, and they are
    willing to sell them to me, if I buy a thousand of them!

    I figured out the schematic as best I can from the PCB layout of the
    charger, and as far as I can tell, there is nothing special about this
    regulator. It simply drops the voltage down to a know quantity (10
    Volts) then through a reverse biased Zener @ 7.2 volts feed the radio
    and battery for charging.

    I think I'm going to drop in a LM7810 (cousin of the LM7805 for 5 volts)
    and take some measurements. The L4810 is only rated at 400mA, where as
    the LM7810 is rated at 1500 mA.

    The 7810 is pin-for-pin compatible (yeah, for all three of them :)

    Yes, I think I'm capable, I've had many, many courses in practical
    electronics, worked in semiconductor manufacturing as a lab bunny, and
    as a equiment tech. My first love is electronics, and HOW IN THE HELL
    did I end up in software engineering? :)




    Thanks for replying.







    Robert Baer wrote:
     
  4. Ken Taylor

    Ken Taylor Guest

    Hi.

    The problem with the LM78xx series is the minimum voltage drop - you will
    lose power far sooner than you would with the original part, as it only
    requires 0.4V, as distinct from (2.something? I forget, but it's greater
    than 0.4!). There are a number of readily available 3-pin regulators which
    are drop-in replacements for the LM78xx, so they may be worth looking at. I
    forget their numbers off-hand too. I need more coffee.....

    Incidentally, NiMH was the way to go, but I made my pack for a Uniden so
    that I could charge the batteries externally - less convenient, but better
    for the batteries and the radio.

    Cheers.

    Ken
     
  5. Robert Baer

    Robert Baer Guest

    You are incorrect; if Mouser has it in their catalog, you could order
    *ONE* and absolutely nothing else.
    Mouser has no minimum order.
    Concerning the LM78xx series, there is a minimum 2 volt drop for
    regulation.
     
  6. sdh

    sdh Guest

    Robert,

    I may be missing something on the Mouser page. I punched in the part
    number, found the part, tried to order four of them. I was reminded that
    I had order 1496 more of them.

    I invite you to try it.


    Steve
     
  7. Robert Baer

    Robert Baer Guest

    Sorry, the minimum i see is 1000 not 2000.
    But that is prolly 999 more thanyou need.
    So call a STM rep and get samples.
     
  8. GPG

    GPG Guest

  9. sdh

    sdh Guest

    I ordered 5 of these from Digi-key - seems to be working.

    Thank you!
     
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