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
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.
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:
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
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.
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
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.
I'm sure there is a replacement part that can be had or to be made to work. http://www.national.com/parametric/0,1850,663-c15-1,00.html LM2937 looks about right.
