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  1. D

    modifying a Velleman kit

    I decided the cheapest way to get battery operation was to buy another 6V gel cell and put it in series with my 12 V...a little bulkier than I would have liked, but it works great. I put in a 15 V VR as you suggested. The battery shows about 18.7 unloaded, and gives a good display when run...
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    modifying a Velleman kit

    OK; thanks for the ideas. I don't really want to take it apart and replace 28 resistors, so I think for now I'll get a different battery. It will be a couple of weeks before I post again, as I'm going to be away all next week. If I replicate this scoreboard, I would consider the different...
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    modifying a Velleman kit

    Sorry for the delay, I waited to get a digital meter. OK, you were right on the money.I tested in 3 states; no load, load comprised of the PCB circuits and the 7-seg LEDs, load of PCB circuits only. My transformer supply readings were 19V, 14.5V, 16.75V repectively. (I was amazed!) The gel cell...
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    modifying a Velleman kit

    I have a new problem with my Velleman display board. When I use a transformer putting out 12 V 1000 mA DC my system runs fine, with all digits bright. (The smaller ones are brighter, but they are better quality than the larger ones.) I need to use this where this is no plug-in for the...
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    modifying a Velleman kit

    Didn't think I'd have time today, but I did..it worked! Thank you so much! I did the voltage drop across the 100 ohm resistor, and it was about 1.2 V. That's spot on isn't it? I just wired through the VR terminals, but I think that I'll get some 12 volt ones in case I ever change the power...
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    modifying a Velleman kit

    Thanks for setting me straight on that...I'll try the suggested remedya soon as I can, but it may be a couple of days before I get the chance. Thanks so much for lending your expertise on this!
  7. D

    modifying a Velleman kit

    Ok, here's a little more info. I checked out the voltage drop across the 100ohm resistor for segment "a" (top of a "7") for the original digit, and I get a drop of about 1.4V.( It's hard to be really accurate because my multitester is analog.) But when I test current across the same resistor I...
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    modifying a Velleman kit

    I just need to check that I understand your suggestion correctly. I take it to mean that I should take out the UA7809 voltage regulator, and replace it with a 7812, and then see if the board will run the new digit. Then I should check the voltage drop across one of the 100 ohm resistors? (Or did...
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    modifying a Velleman kit

    Here is what I've been able to find out: The Velleman kit digits are said to draw 20mA per segment, and the power supply is supposed to be 9-12 Volts. I run mine with an input of 12 volts, but the Velleman digits are rated with a max forward voltage of 9.6, and I guess that's why the circuit...
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    modifying a Velleman kit

    I bought some K8063 kits from Velleman and I like the way I can program the 7-seg LEDs from my PC. Now I have acquired some larger digits, and I'd like to use the same PCBs to drive them, so that all displays can work using the same protocol. The new digits are 5'' tall and I think that they...
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