Andrew C Posted April 6, 2006 Share Posted April 6, 2006 Now I thought we'd done this before, but I can't find it, so... Has anyone converted the signal lamp to LED? If so, is there anything I should beware of before I start? I'm doing it because the fiddly little lamps are always dead when you need them! My main concern is that the lamps / signal circuit need to be in some sort of balance to work, and my theoretical electronics is so old and rusty (never was that hot) I really can't tell. Here is a schematic referred to in a previous thread, but I don't know if it is identical to a TechPro. As I type, I'm starting to remember that there may be a site devoted to this TechPro, but... Link to comment Share on other sites More sharing options...
Brian Posted April 6, 2006 Share Posted April 6, 2006 You have two options... 1/. Modify the actual comms unit which will involve adding a series resistor of around 1k and replacing the lamp with an LED. 2/. Use an LED based replacement for the lamp which takes care of not needing to mod the units. Option 1 is cheap if you don't mind mdding units, option 2 is the easy route. Link to comment Share on other sites More sharing options...
Andrew C Posted April 6, 2006 Author Share Posted April 6, 2006 Thanks Brian. I just wasn't sure if there was any reason NOT to make the change. Planning to go down option (1) route. Link to comment Share on other sites More sharing options...
JonnyD Posted April 7, 2006 Share Posted April 7, 2006 The Tecpro beltpacks now come with Led illumination as standard rather than the lamps which as previously advised is basically a yellow Led and a resistor. Yellow gives an even diffused light spread. Link to comment Share on other sites More sharing options...
Andrew C Posted April 8, 2006 Author Share Posted April 8, 2006 I've done a pair as a prototype, and it is "falling off a log easy". I do need to tweak the limiting resistor/led combination (just used some from the kipple in the bottom spares box) as it isn't quite bright enough. 5mm LED goes straight in, solder to lampholder, snip the jumper to the board and replace with resistor. Link to comment Share on other sites More sharing options...
henny Posted April 8, 2006 Share Posted April 8, 2006 and if you have any old mobile phones kicking around Nick the vibrator motor out of one and connect in Parrnell to the led, great for those who don't keep their headsets on in a noisy environment Link to comment Share on other sites More sharing options...
Andrew C Posted April 11, 2006 Author Share Posted April 11, 2006 http://img.photobucket.com/albums/v225/Andrew_C/DSCN1532.jpg As requested twice by PM. Still need to uprate the LED, but you can see where it goes. The resistor replaces the other piece of green wire from the holder to the underside of the switch. Link to comment Share on other sites More sharing options...
johnhuson Posted May 29, 2009 Share Posted May 29, 2009 Sorry to drag up an old thread, and feeling a bit lazy to work it out. Just wondering what value resistor works best? Link to comment Share on other sites More sharing options...
Andrew C Posted May 29, 2009 Author Share Posted May 29, 2009 Let me consult my copious notes.... Nah, not a clue I'm afraid. I suppose it depends mostly on which LED you choose. Link to comment Share on other sites More sharing options...
themadhippy Posted May 29, 2009 Share Posted May 29, 2009 Looks like a 1K to me,and 21v at 20 ma is 1050 ohms( I think) Link to comment Share on other sites More sharing options...
johnhuson Posted May 29, 2009 Share Posted May 29, 2009 I suppose it depends mostly on which LED you choose. True but I didn't know what voltage the call lamp was but it would appear it's 24v so best go do some maths! Link to comment Share on other sites More sharing options...
johnlinford Posted May 29, 2009 Share Posted May 29, 2009 I suppose it depends mostly on which LED you choose. True but I didn't know what voltage the call lamp was but it would appear it's 24v so best go do some maths! Having done this a few times, it does depend on the LED. Trial and error may be the best approach. I reckon 500R-1K tends to be the range you want to look at. Link to comment Share on other sites More sharing options...
johnhuson Posted May 29, 2009 Share Posted May 29, 2009 My maths have brought me to 820R with the LEDs we've selected so we'll see how we go. Link to comment Share on other sites More sharing options...
spotblaster Posted October 13, 2017 Share Posted October 13, 2017 A few years have passed... Is there now available a direct replacement for the tungsten lamp that just drops in? Same query applies to the Stonewood belt pack call lamp. We have 3 of each! Many Thanks Spotblaster Link to comment Share on other sites More sharing options...
Jevans Posted October 13, 2017 Share Posted October 13, 2017 RS part number 209-377 - they're almost too bright really but drop in replacements. Link to comment Share on other sites More sharing options...
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