toneburst Posted July 19, 2011 Report Share Posted July 19, 2011 Apologies if this has been covered before, but I recently bought a SammichFM kit from Wilba, with the (really nice) neg. green LCD display. I decided to try to put together the base PCB without the jumper to supply a larger voltage to the LCD backlight. The display looks OK, but is quite dim. Should I add this jumper at JR4A? I'm reluctant to try it without confirmation that it won't fry the display. Cheers, a|x Quote Link to comment Share on other sites More sharing options...
Flemming Posted July 20, 2011 Report Share Posted July 20, 2011 The LCD is still dim after you adjust the two trimpots? Quote Link to comment Share on other sites More sharing options...
toneburst Posted July 20, 2011 Author Report Share Posted July 20, 2011 Hi Flemming, it's not very dim- just not as bright as I'd been expecting. I did adjust both trimpots for brightness and clarity of the characters. a|x Quote Link to comment Share on other sites More sharing options...
jbdiver Posted July 20, 2011 Report Share Posted July 20, 2011 I think I had the opposite experience. I've tried it with the jumper in and out. I didn't damage the LCD either way. I think the jumper is out now. The LCD looks acceptable to me. Quote Link to comment Share on other sites More sharing options...
wavecircle Posted August 18, 2011 Report Share Posted August 18, 2011 My backlight is very dim too. I adjust with the trim pots and it just gets fainter until it disappears. Quote Link to comment Share on other sites More sharing options...
Wilba Posted August 19, 2011 Report Share Posted August 19, 2011 All the LCDs I sell now are high-power LCDs and require a shunt in JR4... otherwise the LCD only gets low current (max. 25mA) which is only good for edge-lit LCDs like some white-on-blue LCDs or the amber/true green ones I was selling in the first few batches (before I switched to standard yellow-green LCDs). Quote Link to comment Share on other sites More sharing options...
toneburst Posted September 1, 2011 Author Report Share Posted September 1, 2011 Thanks for the info Wilba. I've installed the jumper, and my LCD is now nice and bright. Cheers, a|x Quote Link to comment Share on other sites More sharing options...
Wilba Posted September 2, 2011 Report Share Posted September 2, 2011 I forgot to add, to keep the current reasonable (100mA) and prolong the life of the LCD, set the brightness pot to half-way or less. Quote Link to comment Share on other sites More sharing options...
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